diff mbox series

[v7,5/7] media: i2c: add DS90UB960 driver

Message ID 20230118124031.788940-6-tomi.valkeinen@ideasonboard.com
State Superseded
Headers show
Series [v7,1/7] i2c: add I2C Address Translator (ATR) support | expand

Commit Message

Tomi Valkeinen Jan. 18, 2023, 12:40 p.m. UTC
Add driver for TI DS90UB960 FPD-Link III Deserializer.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 MAINTAINERS                   |    8 +
 drivers/media/i2c/Kconfig     |   21 +
 drivers/media/i2c/Makefile    |    1 +
 drivers/media/i2c/ds90ub960.c | 4254 +++++++++++++++++++++++++++++++++
 include/media/i2c/ds90ub9xx.h |   16 +
 5 files changed, 4300 insertions(+)
 create mode 100644 drivers/media/i2c/ds90ub960.c
 create mode 100644 include/media/i2c/ds90ub9xx.h

Comments

Andy Shevchenko Jan. 18, 2023, 3:48 p.m. UTC | #1
On Wed, Jan 18, 2023 at 02:40:29PM +0200, Tomi Valkeinen wrote:
> Add driver for TI DS90UB960 FPD-Link III Deserializer.

...

> +#define UB960_MIN_AEQ_STROBE_POS -7

I believe it might need parentheses due to theoretical possibilities to be used
in the expression.

...

> +#define UB960_MIN_MANUAL_STROBE_POS -(7 + 6)

Ditto.

...

> +	ret = regmap_read(priv->regmap, reg, &v);
> +	if (ret)
> +		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
> +			__func__, reg, ret);

Not sure how this messages are useful and esp. parameters, since regmap has
already trace events. Maybe it's possible to narrow regmap traces to the
dedicated functions?

> +	else
> +		*val = v;

...

> +	if (priv->current_read_rxport == nport &&
> +	    priv->current_write_rxport_mask == BIT(nport))
> +		return 0;
> +
> +	ret = regmap_write(priv->regmap, UB960_SR_FPD3_PORT_SEL,
> +			   (nport << 4) | (1 << nport));

Any reason why not BIT() here, while above and below it's being used?

> +	if (ret) {
> +		dev_err(dev, "%s: cannot select rxport %d (%d)!\n", __func__,
> +			nport, ret);
> +		return ret;
> +	}

> +	priv->current_read_rxport = nport;
> +	priv->current_write_rxport_mask = BIT(nport);
> +
> +	return 0;
> +}

...

> +static int _ub960_csiport_select(struct ub960_data *priv, u8 nport)
> +{

Same comment as above.

> +}

...

> +out:

out_unlock: ?

> +	mutex_unlock(&priv->reg_lock);
> +
> +	return ret;

Also in some cases you are using 'else' (as 'if (ret) ... else') in some goto
approach. Can it be unified?

...

> +	v &= ~mask;
> +	v |= val;

Usual pattern we use is

	v = (v & ~mask) | (val & mask);

But can you use regmap_update_bits()? And why not?

...

> +	ret = fwnode_property_count_u32(ep_fwnode, "data-lanes");
> +	if (ret <= 0) {
> +		dev_err(dev, "tx%u: failed to parse 'data-lanes': %d\n", nport,
> +			ret);

Message is not consistent with the case ret == 0.

> +		goto err_free_txport;
> +	}

...

> +	if (ret != 1) {
> +		dev_err(dev,
> +			"tx%u: 'link-frequencies' must contain a single frequency: %d\n",
> +			nport, ret);
> +		goto err_free_txport;
> +	}

Shouldn't be here.
As Rob Herring told at least once that driver must not replace DT validator.

...

> +	if (priv->tx_data_rate != 1600000000 &&
> +	    priv->tx_data_rate != 1200000000 &&
> +	    priv->tx_data_rate != 800000000 &&
> +	    priv->tx_data_rate != 400000000) {
> +		dev_err(dev, "tx%u: invalid 'link-frequencies' value\n", nport);
> +		return -EINVAL;
> +	}

Ditto.

...

> +	dev_dbg(dev, "tx%u: nominal data rate: %u", nport, priv->tx_data_rate);

All these kind of debugging are needed for production?

...

> +static void ub960_csi_handle_events(struct ub960_data *priv, u8 nport)
> +{
> +	struct device *dev = &priv->client->dev;
> +	u8 csi_tx_isr;
> +	int ret;

> +	ret = ub960_csiport_read(priv, nport, UB960_TR_CSI_TX_ISR, &csi_tx_isr);
> +

Redundant blank line.

> +	if (!ret) {

What's wrong with the positive and traditional check, i.e.

	if (ret)
		return;

?

> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR)
> +			dev_warn(dev, "TX%u: CSI_SYNC_ERROR\n", nport);
> +
> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR)
> +			dev_warn(dev, "TX%u: CSI_PASS_ERROR\n", nport);
> +	}
> +}

...

> +/* -----------------------------------------------------------------------------
> + * RX ports
> + */

Multi-line comment is not in the style.

...

> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {

Post-increment is good enough, no? Ditto for other places.
Esp. taking into account that some of them are using actually
post-inc. Why this difference?

> +		struct ub960_rxport *rxport = priv->rxports[nport];
> +
> +		if (!rxport || !rxport->vpoc)
> +			continue;
> +
> +		ret = regulator_enable(rxport->vpoc);
> +		if (ret)
> +			goto err_disable_vpocs;
> +	}

...

> +err_disable_vpocs:
> +	for (; nport > 0; --nport) {

	while (nport--) {

> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
> +
> +		if (!rxport || !rxport->vpoc)
> +			continue;
> +
> +		regulator_disable(rxport->vpoc);
> +	}

...

> +	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
> +		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
> +		return;

Always be careful about WARN*() APIs because with a little trick they may
become equivalent to BUG() which is a beast that nobody likes. I.o.w.
you have to have justify why this is needed and can't be replaced with
dev_*() or analogue.

Same for the other places with WARN*().

...

> +	if (strobe_pos < -7)
> +		clk_delay = abs(strobe_pos) - 6;
> +	else if (strobe_pos > 7)
> +		data_delay = strobe_pos - 6;
> +	else if (strobe_pos < 0)
> +		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
> +	else if (strobe_pos > 0)
> +		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;

I'm wondering if clamp_t()/clamp_val() can be utilised here... And maybe in other
places in the driver.

...

> +	ub960_write(priv, UB960_XR_SFILTER_CFG,

> +		    ((u8)strobe_min << UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT) |
> +		    ((u8)strobe_max << UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT));

Why castings are needed?

...

> +	*eq_level = (v & 0x7) + ((v >> 3) & 0x7);

GENMASK()?


> +	if (eq_level <= 7) {
> +		eq_stage_1_select_value = eq_level;
> +		eq_stage_2_select_value = 0;
> +	} else {
> +		eq_stage_1_select_value = 7;
> +		eq_stage_2_select_value = eq_level - 7;

A lot of magic 7 in the code. Are they all of the same semantic? Are they can
be converted to use a macro (including respective MIN/MAX macros)?

...

> +	WARN_ON(eq_stage_1_select_value > 7);
> +	WARN_ON(eq_stage_2_select_value > 7);

Why WARN()?

...

> +	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
> +
> +	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> +	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
> +	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
> +	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
> +	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
> +
> +	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);

Can't you provide ub960_rxport_update_bits() ?

...

> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
> +	if (ret)
> +		return ret;
> +
> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
> +	if (ret)
> +		return ret;

Can this be read at once as BE16/LE16 value?
Or if the stream of bytes, you can use le/be16_to_cpu().

> +	parity_errors = (v1 << 8) | v2;

...

> +	errors = (rx_port_sts1 & 0x2c) || (rx_port_sts2 & 0x20) ||
> +		 (bcc_sts & 0x3f) || (csi_rx_sts & 0xf) || csi_err_cnt ||

BIT()? GENMASK()?

At bare minimum this needs a good comment to explain all these magics.

> +		 parity_errors;

...

> +	*ok = !errors;

How this is different to the something like returning 1 here (and 0 above)?
You may save some code by dropping redundant parameter.

> +	return 0;

...

> +	while (time_before(jiffies, timeout)) {
> +		missing = 0;
> +
> +		for_each_set_bit(nport, &port_mask,
> +				 priv->hw_data->num_rxports) {
> +			struct ub960_rxport *rxport = priv->rxports[nport];
> +			bool ok;
> +
> +			if (!rxport)
> +				continue;
> +
> +			ret = ub960_rxport_link_ok(priv, nport, &ok);
> +			if (ret)
> +				return ret;
> +
> +			if (!ok || !(link_ok_mask & BIT(nport)))
> +				missing++;
> +
> +			if (ok)
> +				link_ok_mask |= BIT(nport);
> +			else
> +				link_ok_mask &= ~BIT(nport);
> +		}
> +
> +		loops++;
> +
> +		if (missing == 0)
> +			break;
> +
> +		msleep(50);
> +	}

You can wrap the body into readx_poll_timeout() from iopoll.h.

...

> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);

Same Q, can these be unified to some kind of bulk read?

...

> +		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
> +			nport, strobe_pos, eq_level,
> +			v1 * 1000000 + v2 * 1000000 / 256);

Even this will be simpler with above suggestion.

...

> +static int ub960_rxport_add_serializers(struct ub960_data *priv)
> +{
> +	unsigned int nport;
> +	int ret;
> +
> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {

Post-inc?

> +		struct ub960_rxport *rxport = priv->rxports[nport];
> +
> +		if (!rxport)
> +			continue;
> +
> +		ret = ub960_rxport_add_serializer(priv, nport);
> +		if (ret)
> +			goto err_remove_sers;
> +	}
> +
> +	return 0;
> +
> +err_remove_sers:
> +	for (; nport > 0; --nport) {

	while(nport--)

(and drop those -1:s below)

> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
> +
> +		if (!rxport)
> +			continue;
> +
> +		rxport = priv->rxports[nport - 1];
> +		if (!rxport)
> +			continue;
> +
> +		ub960_rxport_remove_serializer(priv, nport - 1);
> +	}
> +
> +	return ret;
> +}

...

> +	if (priv->tx_data_rate == 1600000000)

Easy to make a mistake, perhaps something from units.h / time.h can be used?

> +		csi_ctl |= UB960_TR_CSI_CTL_CSI_CAL_EN;

...

> +	switch (priv->tx_data_rate) {
> +	case 1600000000:
> +	default:
> +		speed_select = 0;
> +		pll_div = 0x10;
> +		break;
> +	case 1200000000:
> +		speed_select = 1;
> +		break;
> +	case 800000000:
> +		speed_select = 2;
> +		pll_div = 0x10;
> +		break;
> +	case 400000000:
> +		speed_select = 3;
> +		pll_div = 0x10;
> +		break;
> +	}

Ditto, but maybe defines for them?

...

> +	switch (rxport->rx_mode) {
> +	default:
> +		WARN_ON(true);
> +		fallthrough;

Maybe you can drop default completely and rely on compiler to produce a
warning?

> +	case RXPORT_MODE_RAW10:
> +		/*
> +		 * RAW10_8BIT_CTL = 0b11 : 8-bit processing using lower 8 bits
> +		 * 0b10 : 8-bit processing using upper 8 bits
> +		 */
> +		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2,
> +					 0x3 << 6, 0x2 << 6);
> +
> +		break;
> +
> +	case RXPORT_MODE_CSI2_SYNC:
> +	case RXPORT_MODE_CSI2_ASYNC:
> +
> +		break;
> +	}

...

> +	u8 cur_vc[UB960_MAX_TX_NPORTS] = { 0 };

0 is not needed.

...

> +	for (i = 0; i < routing->num_routes; ++i) {
> +		struct v4l2_subdev_route *route = &routing->routes[i];
> +		unsigned int rx, tx;
> +
> +		rx = ub960_pad_to_port(priv, route->sink_pad);

> +

Redundant blank line.

> +		if (BIT(rx) & handled_mask)
> +			continue;
> +
> +		tx = ub960_pad_to_port(priv, route->source_pad);
> +
> +		vc[rx] = cur_vc[tx]++;
> +		handled_mask |= BIT(rx);
> +	}

...

> +		if (rx_data[nport].tx_port == 1)
> +			fwd_ctl |= BIT(nport); /* forward to TX1 */
> +		else
> +			fwd_ctl &= ~BIT(nport); /* forward to TX0 */

This and many other similar places can be replaced by __assign_bit()
if the lvalue is type of unsigned long or can be made that type.

...

> +static void ub960_update_streaming_status(struct ub960_data *priv)
> +{
> +	unsigned int i;

> +	bool streaming = false;

Redundant

> +	for (i = 0; i < UB960_MAX_NPORTS; ++i) {
> +		if (priv->stream_enable_mask[i]) {
> +			streaming = true;
> +			break;
> +		}
> +	}

> +	priv->streaming = streaming;

	priv->streaming = i < UB960_MAX_NPORTS;

> +}

...

> +				for (; nport > 0; --nport) {

				while (nport--)

> +					if (pad_stream_masks[nport - 1] == 0)
> +						continue;
> +
> +					ub960_disable_streams(
> +						sd, state,
> +						priv->hw_data->num_rxports +
> +							nport - 1,
> +						pad_stream_masks[nport - 1]);
> +				}

...

> +	char id[7];

u8?

> +	for (unsigned int i = 0; i < 6; ++i)
> +		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
> +	id[6] = 0;

If it's only for printing, the 0 is not needed...

> +	dev_info(dev, "ID '%s'\n", id);

...as you may put it as

	dev_info(dev, "ID: '%.*s'\n", (int)sizeof(id), id);

(I wrote from the top of my head, maybe not compilable as is).

...

> +static irqreturn_t ub960_handle_events(int irq, void *arg)
> +{
> +	struct ub960_data *priv = arg;
> +	unsigned int i;
> +	u8 int_sts;
> +	int ret;

> +	ret = ub960_read(priv, UB960_SR_INTERRUPT_STS, &int_sts);

> +

Redundant blank line. I guess you may decrease your code by ~2.5% by removing
such unneeded blank lines here and there.

> +	if (!ret && int_sts) {

	if (ret)
		return ...

	if (!int_sts)
		return IRQ_NONE; // No?

> +		u8 fwd_sts;
> +
> +		dev_dbg(&priv->client->dev, "INTERRUPT_STS %x\n", int_sts);
> +
> +		ub960_read(priv, UB960_SR_FWD_STS, &fwd_sts);
> +
> +		dev_dbg(&priv->client->dev, "FWD_STS %#02x\n", fwd_sts);
> +
> +		for (i = 0; i < priv->hw_data->num_txports; ++i) {
> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_CSI_TX(i))
> +				ub960_csi_handle_events(priv, i);
> +		}
> +
> +		for (i = 0; i < priv->hw_data->num_rxports; i++) {
> +			if (!priv->rxports[i])
> +				continue;
> +
> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_RX(i))
> +				ub960_rxport_handle_events(priv, i);
> +		}
> +	}

> +	return IRQ_HANDLED;
> +}

...

> +	if (cdr_mode > RXPORT_CDR_LAST) {
> +		dev_err(dev, "rx%u: bad 'ti,cdr-mode' %u\n", nport, cdr_mode);
> +		return -EINVAL;
> +	}

No DT validation if it's not used in (memory) allocation.

...

> +	ret = fwnode_property_read_u32(link_fwnode, "ti,strobe-pos",
> +				       &strobe_pos);
> +	if (ret) {
> +		if (ret != -EINVAL) {
> +			dev_err(dev,
> +				"rx%u: failed to read 'ti,strobe-pos': %d\n",
> +				nport, ret);
> +			return ret;
> +		}
> +	} else if (strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
> +		   strobe_pos > UB960_MAX_MANUAL_STROBE_POS) {
> +		dev_err(dev, "rx%u: illegal 'strobe-pos' value: %d\n", nport,
> +			strobe_pos);
> +	} else {
> +		// NOTE: ignored unless global manual strobe pos is set

Style?

> +		rxport->eq.strobe_pos = strobe_pos;
> +		if (!priv->strobe.manual)
> +			dev_warn(dev,
> +				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
> +				 nport);
> +	}

This and below looks a bit different to the above in the same function. Perhaps
these can be refactored to be less LoCs.

> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> +	if (ret) {
> +		if (ret != -EINVAL) {
> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> +				nport, ret);
> +			return ret;
> +		}
> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> +			eq_level);
> +	} else {
> +		rxport->eq.manual_eq = true;
> +		rxport->eq.manual.eq_level = eq_level;
> +	}
> +
> +	ret = fwnode_property_read_u32(link_fwnode, "i2c-alias",
> +				       &ser_i2c_alias);
> +	if (ret) {
> +		dev_err(dev, "rx%u: failed to read 'i2c-alias': %d\n", nport,
> +			ret);
> +		return ret;
> +	}

...

> +static struct fwnode_handle *
> +ub960_fwnode_get_link_by_regs(struct fwnode_handle *links_fwnode,
> +			      unsigned int nport)
> +{
> +	struct fwnode_handle *link_fwnode;
> +	int ret;
> +
> +	fwnode_for_each_child_node(links_fwnode, link_fwnode) {
> +		u32 link_num;
> +
> +		if (strncmp(fwnode_get_name(link_fwnode), "link@", 5) != 0)
> +			continue;

str_has_prefix()

> +
> +		ret = fwnode_property_read_u32(link_fwnode, "reg", &link_num);
> +		if (ret)

Refcount imbalance.

> +			return NULL;
> +
> +		if (nport == link_num) {
> +			fwnode_handle_put(link_fwnode);
> +			return link_fwnode;
> +		}
> +	}
> +
> +	return NULL;
> +}

...

> +		asd = v4l2_async_nf_add_fwnode(&priv->notifier,
> +					       rxport->source_ep_fwnode,
> +					       struct ub960_asd);
> +		if (IS_ERR(asd)) {
> +			dev_err(dev, "Failed to add subdev for source %u: %ld",

%pe ?

> +				i, PTR_ERR(asd));
> +			v4l2_async_nf_cleanup(&priv->notifier);
> +			return PTR_ERR(asd);
> +		}

...

> +err_pd_gpio:
> +	if (priv->pd_gpio)

Dup test.

> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);

...

> +	if (priv->pd_gpio)
> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);

Ditto.

...

> +	priv->hw_data = of_device_get_match_data(dev);

Why of_ out of the blue?!

> +	if (!priv->hw_data)
> +		return -ENODEV;

...

> +	priv->current_indirect_target = 0xff;
> +	priv->current_read_rxport = 0xff;
> +	priv->current_write_rxport_mask = 0xff;
> +	priv->current_read_csiport = 0xff;
> +	priv->current_write_csiport_mask = 0xff;

GENMASK()

...

> +	ub960_rxport_wait_locks(priv, 0xf, NULL);

Ditto?

...

> +static const struct i2c_device_id ub960_id[] = {
> +	{ "ds90ub960-q1", 0 },
> +	{ "ds90ub9702-q1", 0 },

Why driver data is different to OF case?

> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ub960_id);
> +
> +static const struct of_device_id ub960_dt_ids[] = {
> +	{ .compatible = "ti,ds90ub960-q1", .data = &ds90ub960_hw },
> +	{ .compatible = "ti,ds90ub9702-q1", .data = &ds90ub9702_hw },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ub960_dt_ids);

> +static struct i2c_driver ds90ub960_driver = {
> +	.probe_new	= ub960_probe,
> +	.remove		= ub960_remove,
> +	.id_table	= ub960_id,
> +	.driver = {
> +		.name	= "ds90ub960",

> +		.owner = THIS_MODULE,

Set by macro from the beginning of its, macro, existence.

> +		.of_match_table = ub960_dt_ids,
> +	},
> +};

...

> +struct ds90ub9xx_platform_data {
> +	u32 port;
> +	struct i2c_atr *atr;
> +	unsigned long bc_rate;

Not sure why we need this to be public except, probably, atr...
Tomi Valkeinen Jan. 19, 2023, 4:27 p.m. UTC | #2
Hi Andy,

Thanks for the thorough review!

On 18/01/2023 17:48, Andy Shevchenko wrote:
> On Wed, Jan 18, 2023 at 02:40:29PM +0200, Tomi Valkeinen wrote:
>> Add driver for TI DS90UB960 FPD-Link III Deserializer.
> 
> ...
> 
>> +#define UB960_MIN_AEQ_STROBE_POS -7
> 
> I believe it might need parentheses due to theoretical possibilities to be used
> in the expression.

Hmm, for my education, in which kind of expressions this could cause an 
issue?

> ...
> 
>> +#define UB960_MIN_MANUAL_STROBE_POS -(7 + 6)
> 
> Ditto.
> 
> ...
> 
>> +	ret = regmap_read(priv->regmap, reg, &v);
>> +	if (ret)
>> +		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
>> +			__func__, reg, ret);
> 
> Not sure how this messages are useful and esp. parameters, since regmap has
> already trace events. Maybe it's possible to narrow regmap traces to the
> dedicated functions?

I have found the error prints useful on multiple occasions. If something 
goes wrong, I'd rather see it immediately. And isn't tracing and error 
printing quite different things? What is your concern here, or rather, 
what would you suggest instead of the above?

>> +	else
>> +		*val = v;
> 
> ...
> 
>> +	if (priv->current_read_rxport == nport &&
>> +	    priv->current_write_rxport_mask == BIT(nport))
>> +		return 0;
>> +
>> +	ret = regmap_write(priv->regmap, UB960_SR_FPD3_PORT_SEL,
>> +			   (nport << 4) | (1 << nport));
> 
> Any reason why not BIT() here, while above and below it's being used?

No reason.

>> +	if (ret) {
>> +		dev_err(dev, "%s: cannot select rxport %d (%d)!\n", __func__,
>> +			nport, ret);
>> +		return ret;
>> +	}
> 
>> +	priv->current_read_rxport = nport;
>> +	priv->current_write_rxport_mask = BIT(nport);
>> +
>> +	return 0;
>> +}
> 
> ...
> 
>> +static int _ub960_csiport_select(struct ub960_data *priv, u8 nport)
>> +{
> 
> Same comment as above.
> 
>> +}
> 
> ...
> 
>> +out:
> 
> out_unlock: ?

I'll change it, but often if there's only one label, I think just 
err/out is fine.

>> +	mutex_unlock(&priv->reg_lock);
>> +
>> +	return ret;
> 
> Also in some cases you are using 'else' (as 'if (ret) ... else') in some goto
> approach. Can it be unified?

Sure.

> ...
> 
>> +	v &= ~mask;
>> +	v |= val;
> 
> Usual pattern we use is
> 
> 	v = (v & ~mask) | (val & mask);
> 
> But can you use regmap_update_bits()? And why not?

I don't see why not. No idea why I open-coded it.

> ...
> 
>> +	ret = fwnode_property_count_u32(ep_fwnode, "data-lanes");
>> +	if (ret <= 0) {
>> +		dev_err(dev, "tx%u: failed to parse 'data-lanes': %d\n", nport,
>> +			ret);
> 
> Message is not consistent with the case ret == 0.

Yep.

>> +		goto err_free_txport;
>> +	}
> 
> ...
> 
>> +	if (ret != 1) {
>> +		dev_err(dev,
>> +			"tx%u: 'link-frequencies' must contain a single frequency: %d\n",
>> +			nport, ret);
>> +		goto err_free_txport;
>> +	}
> 
> Shouldn't be here.
> As Rob Herring told at least once that driver must not replace DT validator.

Ok. Hmm, looks like link-frequencies is not even in the binding doc. 
I'll add it.

> ...
> 
>> +	if (priv->tx_data_rate != 1600000000 &&
>> +	    priv->tx_data_rate != 1200000000 &&
>> +	    priv->tx_data_rate != 800000000 &&
>> +	    priv->tx_data_rate != 400000000) {
>> +		dev_err(dev, "tx%u: invalid 'link-frequencies' value\n", nport);
>> +		return -EINVAL;
>> +	}
> 
> Ditto.

Is that an important thing to restrict in the DT? I'd rather handle 
these in the driver. There may well be HW revisions/versions or tricks 
not documented in the public docs to use other data rates. And, while 
this is not quite clear to me, the input refclk might also affect the 
exact data rate.

With a quick glance, I don't see any other binding defining the data 
rates. I didn't see any of them even limiting the number of items.

> ...
> 
>> +	dev_dbg(dev, "tx%u: nominal data rate: %u", nport, priv->tx_data_rate);
> 
> All these kind of debugging are needed for production?

Production meaning upstream kernel? Hard to say. I find all kinds of 
debugging prints useful.

> ...
> 
>> +static void ub960_csi_handle_events(struct ub960_data *priv, u8 nport)
>> +{
>> +	struct device *dev = &priv->client->dev;
>> +	u8 csi_tx_isr;
>> +	int ret;
> 
>> +	ret = ub960_csiport_read(priv, nport, UB960_TR_CSI_TX_ISR, &csi_tx_isr);
>> +
> 
> Redundant blank line.

Yep.

>> +	if (!ret) {
> 
> What's wrong with the positive and traditional check, i.e.
> 
> 	if (ret)
> 		return;
> 
> ?

Nothing, just a different style. I can change it.

>> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR)
>> +			dev_warn(dev, "TX%u: CSI_SYNC_ERROR\n", nport);
>> +
>> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR)
>> +			dev_warn(dev, "TX%u: CSI_PASS_ERROR\n", nport);
>> +	}
>> +}
> 
> ...
> 
>> +/* -----------------------------------------------------------------------------
>> + * RX ports
>> + */
> 
> Multi-line comment is not in the style.

True. Interesting that checkpatch didn't complain.

> ...
> 
>> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> 
> Post-increment is good enough, no? Ditto for other places.

Sure. Pre-increment is good enough too, right? It's a simpler operation, 
although obviously they both compile into the same code. I usually use 
pre-increment when there's no particular reason to pick either one, 
although it also depends on how it looks.

> Esp. taking into account that some of them are using actually
> post-inc. Why this difference?

Possibly a different person has written that particular piece of code, 
or maybe a copy paste from somewhere.

I'm personally fine with seeing both post and pre increments in code.

>> +		struct ub960_rxport *rxport = priv->rxports[nport];
>> +
>> +		if (!rxport || !rxport->vpoc)
>> +			continue;
>> +
>> +		ret = regulator_enable(rxport->vpoc);
>> +		if (ret)
>> +			goto err_disable_vpocs;
>> +	}
> 
> ...
> 
>> +err_disable_vpocs:
>> +	for (; nport > 0; --nport) {
> 
> 	while (nport--) {

Yes, that's better.

>> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
>> +
>> +		if (!rxport || !rxport->vpoc)
>> +			continue;
>> +
>> +		regulator_disable(rxport->vpoc);
>> +	}
> 
> ...
> 
>> +	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
>> +		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
>> +		return;
> 
> Always be careful about WARN*() APIs because with a little trick they may
> become equivalent to BUG() which is a beast that nobody likes. I.o.w.
> you have to have justify why this is needed and can't be replaced with
> dev_*() or analogue.
> 
> Same for the other places with WARN*().

Valid point. I think most of them here are in cases that really 
shouldn't happen. But if they do happen, I'd like to see a big loud 
shout about it. The above is not a best example of this, and I think I 
can just drop the above warns, but, e.g. handling the default case for 
"switch (rxport->rx_mode)" (which shouldn't happen), I'd prefer to have 
a big yell in place rather than return silently or print a "normal" 
error print.

Obviously WARN is not a good one if it can be toggled to become a BUG.

So... I think I'll just drop most of them and probably convert the rest 
(two, actually) to dev_errs.

> ...
> 
>> +	if (strobe_pos < -7)
>> +		clk_delay = abs(strobe_pos) - 6;
>> +	else if (strobe_pos > 7)
>> +		data_delay = strobe_pos - 6;
>> +	else if (strobe_pos < 0)
>> +		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
>> +	else if (strobe_pos > 0)
>> +		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
> 
> I'm wondering if clamp_t()/clamp_val() can be utilised here... And maybe in other
> places in the driver.

Hmm, I'm not sure how.

> ...
> 
>> +	ub960_write(priv, UB960_XR_SFILTER_CFG,
> 
>> +		    ((u8)strobe_min << UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT) |
>> +		    ((u8)strobe_max << UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT));
> 
> Why castings are needed?

I don't think they strictly are, but it highlights that the variables, 
which are signed, are now >= 0, and are used as unsigned.

> ...
> 
>> +	*eq_level = (v & 0x7) + ((v >> 3) & 0x7);
> 
> GENMASK()?

I'll add defines for these bit fields.

> 
>> +	if (eq_level <= 7) {
>> +		eq_stage_1_select_value = eq_level;
>> +		eq_stage_2_select_value = 0;
>> +	} else {
>> +		eq_stage_1_select_value = 7;
>> +		eq_stage_2_select_value = eq_level - 7;
> 
> A lot of magic 7 in the code. Are they all of the same semantic? Are they can
> be converted to use a macro (including respective MIN/MAX macros)?

It's related to how the value has to be encoded into the register. We 
keep the equalization level in a simple variable, but need to write it 
like this into the register. I'm not sure what I would call the magic 7 
here.

Then for the strobe position, we use a logical signed value between -7 
and 7, so we have to +7 when writing that to a register. Except when 
using a manual strobe position, where the range is -13 to 13 (7+6, 
that's the 6 in ub960_rxport_set_strobe_pos()).

It's rather confusing, in my opinion, but I think defines may just make 
this more confusing. The magic numbers used should always be very close 
to the registers in question, so if you know how the HW works wrt. 
strobe & eq, they should be "clear". I'll try to come up with defines 
that make this clearer, but no promises.

> ...
> 
>> +	WARN_ON(eq_stage_1_select_value > 7);
>> +	WARN_ON(eq_stage_2_select_value > 7);
> 
> Why WARN()?

I'll drop. I think these were development time helpers long time back.

> ...
> 
>> +	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
>> +
>> +	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
>> +	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
>> +	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
>> +	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
>> +	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
>> +
>> +	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);
> 
> Can't you provide ub960_rxport_update_bits() ?

I could, but I think it's worse:

ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
		UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
		UB960_RR_AEQ_BYPASS_ENABLE,
	(eq_stage_1_select_value
	 << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
		(eq_stage_2_select_value
		 << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
		UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
);

Indenting it differently, I think it's still worse:

ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
	UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
	UB960_RR_AEQ_BYPASS_ENABLE,
	(eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
	(eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
	UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
);

> ...
> 
>> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
>> +	if (ret)
>> +		return ret;
> 
> Can this be read at once as BE16/LE16 value?
> Or if the stream of bytes, you can use le/be16_to_cpu().

I'm not sure, possibly. But is it worth it? I'd need to add new helper 
functions to read such a value.

>> +	parity_errors = (v1 << 8) | v2;
> 
> ...
> 
>> +	errors = (rx_port_sts1 & 0x2c) || (rx_port_sts2 & 0x20) ||
>> +		 (bcc_sts & 0x3f) || (csi_rx_sts & 0xf) || csi_err_cnt ||
> 
> BIT()? GENMASK()?

I'll add defines for the error masks (those are bit masks of error bits 
in the registers).

> At bare minimum this needs a good comment to explain all these magics.
> 
>> +		 parity_errors;
> 
> ...
> 
>> +	*ok = !errors;
> 
> How this is different to the something like returning 1 here (and 0 above)?
> You may save some code by dropping redundant parameter.

Return value 1 means there was an error when reading the register 
values. 0 means we read the values, and "ok" contains a summary (ok or 
not) of the link's status.

>> +	return 0;
> 
> ...
> 
>> +	while (time_before(jiffies, timeout)) {
>> +		missing = 0;
>> +
>> +		for_each_set_bit(nport, &port_mask,
>> +				 priv->hw_data->num_rxports) {
>> +			struct ub960_rxport *rxport = priv->rxports[nport];
>> +			bool ok;
>> +
>> +			if (!rxport)
>> +				continue;
>> +
>> +			ret = ub960_rxport_link_ok(priv, nport, &ok);
>> +			if (ret)
>> +				return ret;
>> +
>> +			if (!ok || !(link_ok_mask & BIT(nport)))
>> +				missing++;
>> +
>> +			if (ok)
>> +				link_ok_mask |= BIT(nport);
>> +			else
>> +				link_ok_mask &= ~BIT(nport);
>> +		}
>> +
>> +		loops++;
>> +
>> +		if (missing == 0)
>> +			break;
>> +
>> +		msleep(50);
>> +	}
> 
> You can wrap the body into readx_poll_timeout() from iopoll.h.

Hmm... How would I do that? With some kind of helper structs to wrap the 
input and output parameters? Sounds very messy, but maybe I'm missing 
something.

> ...
> 
>> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
>> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
> 
> Same Q, can these be unified to some kind of bulk read?

Perhaps, but again, I don't see the value for creating a bulk read 
helper function for these few cases.

> ...
> 
>> +		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
>> +			nport, strobe_pos, eq_level,
>> +			v1 * 1000000 + v2 * 1000000 / 256);
> 
> Even this will be simpler with above suggestion.

Hmm... How is that?

> ...
> 
>> +static int ub960_rxport_add_serializers(struct ub960_data *priv)
>> +{
>> +	unsigned int nport;
>> +	int ret;
>> +
>> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> 
> Post-inc?

I still like pre-inc =).

I see there's a mix os post and pre incs in the code. I'll align those 
when I encounter them, but I don't think it's worth the effort to 
methodically go through all of them to change them use the same style.

>> +		struct ub960_rxport *rxport = priv->rxports[nport];
>> +
>> +		if (!rxport)
>> +			continue;
>> +
>> +		ret = ub960_rxport_add_serializer(priv, nport);
>> +		if (ret)
>> +			goto err_remove_sers;
>> +	}
>> +
>> +	return 0;
>> +
>> +err_remove_sers:
>> +	for (; nport > 0; --nport) {
> 
> 	while(nport--)
> 
> (and drop those -1:s below)

Yes, that cleans this up nicely.

>> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
>> +
>> +		if (!rxport)
>> +			continue;
>> +
>> +		rxport = priv->rxports[nport - 1];
>> +		if (!rxport)
>> +			continue;
>> +
>> +		ub960_rxport_remove_serializer(priv, nport - 1);
>> +	}
>> +
>> +	return ret;
>> +}
> 
> ...
> 
>> +	if (priv->tx_data_rate == 1600000000)
> 
> Easy to make a mistake, perhaps something from units.h / time.h can be used?

Hmm, time.h? What's in there.

I don't like the HZ_PER_MHZ too much. But I'll add this, which I 
recently added to a Renesas driver:

#define MHZ(v) ((u32)((v) * 1000000U))

I like it, as e.g. MHZ(1.6) works and (I think) is quite clear. Here 
it's MHZ(1600), of course.

>> +		csi_ctl |= UB960_TR_CSI_CTL_CSI_CAL_EN;
> 
> ...
> 
>> +	switch (priv->tx_data_rate) {
>> +	case 1600000000:
>> +	default:
>> +		speed_select = 0;
>> +		pll_div = 0x10;
>> +		break;
>> +	case 1200000000:
>> +		speed_select = 1;
>> +		break;
>> +	case 800000000:
>> +		speed_select = 2;
>> +		pll_div = 0x10;
>> +		break;
>> +	case 400000000:
>> +		speed_select = 3;
>> +		pll_div = 0x10;
>> +		break;
>> +	}
> 
> Ditto, but maybe defines for them?
> 
> ...
> 
>> +	switch (rxport->rx_mode) {
>> +	default:
>> +		WARN_ON(true);
>> +		fallthrough;
> 
> Maybe you can drop default completely and rely on compiler to produce a
> warning?

I've dropped the default, but I had to add cases for the RAW12 modes 
(which are not supported at the moment).

>> +	case RXPORT_MODE_RAW10:
>> +		/*
>> +		 * RAW10_8BIT_CTL = 0b11 : 8-bit processing using lower 8 bits
>> +		 * 0b10 : 8-bit processing using upper 8 bits
>> +		 */
>> +		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2,
>> +					 0x3 << 6, 0x2 << 6);
>> +
>> +		break;
>> +
>> +	case RXPORT_MODE_CSI2_SYNC:
>> +	case RXPORT_MODE_CSI2_ASYNC:
>> +
>> +		break;
>> +	}
> 
> ...
> 
>> +	u8 cur_vc[UB960_MAX_TX_NPORTS] = { 0 };
> 
> 0 is not needed.

Yep.

> ...
> 
>> +	for (i = 0; i < routing->num_routes; ++i) {
>> +		struct v4l2_subdev_route *route = &routing->routes[i];
>> +		unsigned int rx, tx;
>> +
>> +		rx = ub960_pad_to_port(priv, route->sink_pad);
> 
>> +
> 
> Redundant blank line.

Yep.

>> +		if (BIT(rx) & handled_mask)
>> +			continue;
>> +
>> +		tx = ub960_pad_to_port(priv, route->source_pad);
>> +
>> +		vc[rx] = cur_vc[tx]++;
>> +		handled_mask |= BIT(rx);
>> +	}
> 
> ...
> 
>> +		if (rx_data[nport].tx_port == 1)
>> +			fwd_ctl |= BIT(nport); /* forward to TX1 */
>> +		else
>> +			fwd_ctl &= ~BIT(nport); /* forward to TX0 */
> 
> This and many other similar places can be replaced by __assign_bit()
> if the lvalue is type of unsigned long or can be made that type.

It is u8, as it is written to a 8 bit register. It could be made 
unsigned long, but... I'd rather use u8 when we are dealing with 8 bits 
of data.

> ...
> 
>> +static void ub960_update_streaming_status(struct ub960_data *priv)
>> +{
>> +	unsigned int i;
> 
>> +	bool streaming = false;
> 
> Redundant
> >> +	for (i = 0; i < UB960_MAX_NPORTS; ++i) {
>> +		if (priv->stream_enable_mask[i]) {
>> +			streaming = true;
>> +			break;
>> +		}
>> +	}
> 
>> +	priv->streaming = streaming;
> 
> 	priv->streaming = i < UB960_MAX_NPORTS;

Yes, that's a bit simpler.

>> +}
> 
> ...
> 
>> +				for (; nport > 0; --nport) {
> 
> 				while (nport--)

Yep.

>> +					if (pad_stream_masks[nport - 1] == 0)
>> +						continue;
>> +
>> +					ub960_disable_streams(
>> +						sd, state,
>> +						priv->hw_data->num_rxports +
>> +							nport - 1,
>> +						pad_stream_masks[nport - 1]);
>> +				}
> 
> ...
> 
>> +	char id[7];
> 
> u8?
> 
>> +	for (unsigned int i = 0; i < 6; ++i)
>> +		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
>> +	id[6] = 0;
> 
> If it's only for printing, the 0 is not needed...
> 
>> +	dev_info(dev, "ID '%s'\n", id);
> 
> ...as you may put it as
> 
> 	dev_info(dev, "ID: '%.*s'\n", (int)sizeof(id), id);
> 
> (I wrote from the top of my head, maybe not compilable as is).

And you think that is clearer? =) I have to disagree.

> ...
> 
>> +static irqreturn_t ub960_handle_events(int irq, void *arg)
>> +{
>> +	struct ub960_data *priv = arg;
>> +	unsigned int i;
>> +	u8 int_sts;
>> +	int ret;
> 
>> +	ret = ub960_read(priv, UB960_SR_INTERRUPT_STS, &int_sts);
> 
>> +
> 
> Redundant blank line. I guess you may decrease your code by ~2.5% by removing
> such unneeded blank lines here and there.

I only found a few of these, which I have fixed.

>> +	if (!ret && int_sts) {
> 
> 	if (ret)
> 		return ...
> 
> 	if (!int_sts)
> 		return IRQ_NONE; // No?

Yes, I think that's correct. I wonder what to return in the (ret) case. 
Probably also IRQ_NONE, as we don't know if the interrupt was for us.

>> +		u8 fwd_sts;
>> +
>> +		dev_dbg(&priv->client->dev, "INTERRUPT_STS %x\n", int_sts);
>> +
>> +		ub960_read(priv, UB960_SR_FWD_STS, &fwd_sts);
>> +
>> +		dev_dbg(&priv->client->dev, "FWD_STS %#02x\n", fwd_sts);
>> +
>> +		for (i = 0; i < priv->hw_data->num_txports; ++i) {
>> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_CSI_TX(i))
>> +				ub960_csi_handle_events(priv, i);
>> +		}
>> +
>> +		for (i = 0; i < priv->hw_data->num_rxports; i++) {
>> +			if (!priv->rxports[i])
>> +				continue;
>> +
>> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_RX(i))
>> +				ub960_rxport_handle_events(priv, i);
>> +		}
>> +	}
> 
>> +	return IRQ_HANDLED;
>> +}
> 
> ...
> 
>> +	if (cdr_mode > RXPORT_CDR_LAST) {
>> +		dev_err(dev, "rx%u: bad 'ti,cdr-mode' %u\n", nport, cdr_mode);
>> +		return -EINVAL;
>> +	}
> 
> No DT validation if it's not used in (memory) allocation.

I'm not quite fine with dropping all these DT checks. If the user 
happens to provide a DT with illegal values, the end results can be odd 
and the reason quite difficult to figure out. Isn't it much better to 
have a few extra checks in the driver?

> ...
> 
>> +	ret = fwnode_property_read_u32(link_fwnode, "ti,strobe-pos",
>> +				       &strobe_pos);
>> +	if (ret) {
>> +		if (ret != -EINVAL) {
>> +			dev_err(dev,
>> +				"rx%u: failed to read 'ti,strobe-pos': %d\n",
>> +				nport, ret);
>> +			return ret;
>> +		}
>> +	} else if (strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
>> +		   strobe_pos > UB960_MAX_MANUAL_STROBE_POS) {
>> +		dev_err(dev, "rx%u: illegal 'strobe-pos' value: %d\n", nport,
>> +			strobe_pos);
>> +	} else {
>> +		// NOTE: ignored unless global manual strobe pos is set
> 
> Style?

Oops...

>> +		rxport->eq.strobe_pos = strobe_pos;
>> +		if (!priv->strobe.manual)
>> +			dev_warn(dev,
>> +				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
>> +				 nport);
>> +	}
> 
> This and below looks a bit different to the above in the same function. Perhaps
> these can be refactored to be less LoCs.

Hmm what did you have in mind?

>> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
>> +	if (ret) {
>> +		if (ret != -EINVAL) {
>> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
>> +				nport, ret);
>> +			return ret;
>> +		}
>> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
>> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
>> +			eq_level);
>> +	} else {
>> +		rxport->eq.manual_eq = true;
>> +		rxport->eq.manual.eq_level = eq_level;
>> +	}
>> +
>> +	ret = fwnode_property_read_u32(link_fwnode, "i2c-alias",
>> +				       &ser_i2c_alias);
>> +	if (ret) {
>> +		dev_err(dev, "rx%u: failed to read 'i2c-alias': %d\n", nport,
>> +			ret);
>> +		return ret;
>> +	}
> 
> ...
> 
>> +static struct fwnode_handle *
>> +ub960_fwnode_get_link_by_regs(struct fwnode_handle *links_fwnode,
>> +			      unsigned int nport)
>> +{
>> +	struct fwnode_handle *link_fwnode;
>> +	int ret;
>> +
>> +	fwnode_for_each_child_node(links_fwnode, link_fwnode) {
>> +		u32 link_num;
>> +
>> +		if (strncmp(fwnode_get_name(link_fwnode), "link@", 5) != 0)
>> +			continue;
> 
> str_has_prefix()

I knew there must be a function for this, but didn't find it =).

>> +
>> +		ret = fwnode_property_read_u32(link_fwnode, "reg", &link_num);
>> +		if (ret)
> 
> Refcount imbalance.

Yep.

>> +			return NULL;
>> +
>> +		if (nport == link_num) {
>> +			fwnode_handle_put(link_fwnode);
>> +			return link_fwnode;
>> +		}
>> +	}
>> +
>> +	return NULL;
>> +}
> 
> ...
> 
>> +		asd = v4l2_async_nf_add_fwnode(&priv->notifier,
>> +					       rxport->source_ep_fwnode,
>> +					       struct ub960_asd);
>> +		if (IS_ERR(asd)) {
>> +			dev_err(dev, "Failed to add subdev for source %u: %ld",
> 
> %pe ?

Yep.

>> +				i, PTR_ERR(asd));
>> +			v4l2_async_nf_cleanup(&priv->notifier);
>> +			return PTR_ERR(asd);
>> +		}
> 
> ...
> 
>> +err_pd_gpio:
>> +	if (priv->pd_gpio)
> 
> Dup test.

What do you mean dup? You mean gpiod_set_value_cansleep can be called 
with gpio = NULL? The docs don't say this, but I guess that is the case.

>> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> 
> ...
> 
>> +	if (priv->pd_gpio)
>> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> 
> Ditto.
> 
> ...
> 
>> +	priv->hw_data = of_device_get_match_data(dev);
> 
> Why of_ out of the blue?!

Hmm... How do I get the data in a generic way? I'll have to study this a 
bit.

>> +	if (!priv->hw_data)
>> +		return -ENODEV;
> 
> ...
> 
>> +	priv->current_indirect_target = 0xff;
>> +	priv->current_read_rxport = 0xff;
>> +	priv->current_write_rxport_mask = 0xff;
>> +	priv->current_read_csiport = 0xff;
>> +	priv->current_write_csiport_mask = 0xff;
> 
> GENMASK()

These are not masks, but invalid values. We set these to an invalid 
value (0xff) so that when a reg access function next time checks if we 
are already targeting, e.g. a particular rxport, it will always opt to 
select the rxport by writing to the approriate registers.

> ...
> 
>> +	ub960_rxport_wait_locks(priv, 0xf, NULL);
> 
> Ditto?

Yep.

> ...
> 
>> +static const struct i2c_device_id ub960_id[] = {
>> +	{ "ds90ub960-q1", 0 },
>> +	{ "ds90ub9702-q1", 0 },
> 
> Why driver data is different to OF case?

I have just never used these so I've missed it. As I said, I need to 
look at this and figure out how to get the data correctly in all the cases.

>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ub960_id);
>> +
>> +static const struct of_device_id ub960_dt_ids[] = {
>> +	{ .compatible = "ti,ds90ub960-q1", .data = &ds90ub960_hw },
>> +	{ .compatible = "ti,ds90ub9702-q1", .data = &ds90ub9702_hw },
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(of, ub960_dt_ids);
> 
>> +static struct i2c_driver ds90ub960_driver = {
>> +	.probe_new	= ub960_probe,
>> +	.remove		= ub960_remove,
>> +	.id_table	= ub960_id,
>> +	.driver = {
>> +		.name	= "ds90ub960",
> 
>> +		.owner = THIS_MODULE,
> 
> Set by macro from the beginning of its, macro, existence.

Ok.

>> +		.of_match_table = ub960_dt_ids,
>> +	},
>> +};
> 
> ...
> 
>> +struct ds90ub9xx_platform_data {
>> +	u32 port;
>> +	struct i2c_atr *atr;
>> +	unsigned long bc_rate;
> 
> Not sure why we need this to be public except, probably, atr...

The port and atr are used by the serializers, for atr. The bc_rate is 
used by the serializers to figure out the clocking (they may use the 
FPD-Link's frequency internally).

  Tomi
Laurent Pinchart Jan. 19, 2023, 11:19 p.m. UTC | #3
On Thu, Jan 19, 2023 at 06:27:31PM +0200, Tomi Valkeinen wrote:
> Hi Andy,
> 
> Thanks for the thorough review!
> 
> On 18/01/2023 17:48, Andy Shevchenko wrote:
> > On Wed, Jan 18, 2023 at 02:40:29PM +0200, Tomi Valkeinen wrote:
> >> Add driver for TI DS90UB960 FPD-Link III Deserializer.
> > 
> > ...
> > 
> >> +#define UB960_MIN_AEQ_STROBE_POS -7
> > 
> > I believe it might need parentheses due to theoretical possibilities to be used
> > in the expression.
> 
> Hmm, for my education, in which kind of expressions this could cause an 
> issue?
> 
> > ...
> > 
> >> +#define UB960_MIN_MANUAL_STROBE_POS -(7 + 6)
> > 
> > Ditto.
> > 
> > ...
> > 
> >> +	ret = regmap_read(priv->regmap, reg, &v);
> >> +	if (ret)
> >> +		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
> >> +			__func__, reg, ret);
> > 
> > Not sure how this messages are useful and esp. parameters, since regmap has
> > already trace events. Maybe it's possible to narrow regmap traces to the
> > dedicated functions?
> 
> I have found the error prints useful on multiple occasions. If something 
> goes wrong, I'd rather see it immediately. And isn't tracing and error 
> printing quite different things? What is your concern here, or rather, 
> what would you suggest instead of the above?

I agree, if I2C transfers fail, we want to see errors immediately. If
that can be handled by regmap, that's great, but if the user has to
enable tracing manually, that's not a good option.

> >> +	else
> >> +		*val = v;
> > 
> > ...
> > 
> >> +	if (priv->current_read_rxport == nport &&
> >> +	    priv->current_write_rxport_mask == BIT(nport))
> >> +		return 0;
> >> +
> >> +	ret = regmap_write(priv->regmap, UB960_SR_FPD3_PORT_SEL,
> >> +			   (nport << 4) | (1 << nport));
> > 
> > Any reason why not BIT() here, while above and below it's being used?
> 
> No reason.
> 
> >> +	if (ret) {
> >> +		dev_err(dev, "%s: cannot select rxport %d (%d)!\n", __func__,
> >> +			nport, ret);
> >> +		return ret;
> >> +	}
> > 
> >> +	priv->current_read_rxport = nport;
> >> +	priv->current_write_rxport_mask = BIT(nport);
> >> +
> >> +	return 0;
> >> +}
> > 
> > ...
> > 
> >> +static int _ub960_csiport_select(struct ub960_data *priv, u8 nport)
> >> +{
> > 
> > Same comment as above.
> > 
> >> +}
> > 
> > ...
> > 
> >> +out:
> > 
> > out_unlock: ?
> 
> I'll change it, but often if there's only one label, I think just 
> err/out is fine.
> 
> >> +	mutex_unlock(&priv->reg_lock);
> >> +
> >> +	return ret;
> > 
> > Also in some cases you are using 'else' (as 'if (ret) ... else') in some goto
> > approach. Can it be unified?
> 
> Sure.
> 
> > ...
> > 
> >> +	v &= ~mask;
> >> +	v |= val;
> > 
> > Usual pattern we use is
> > 
> > 	v = (v & ~mask) | (val & mask);
> > 
> > But can you use regmap_update_bits()? And why not?
> 
> I don't see why not. No idea why I open-coded it.
> 
> > ...
> > 
> >> +	ret = fwnode_property_count_u32(ep_fwnode, "data-lanes");
> >> +	if (ret <= 0) {
> >> +		dev_err(dev, "tx%u: failed to parse 'data-lanes': %d\n", nport,
> >> +			ret);
> > 
> > Message is not consistent with the case ret == 0.
> 
> Yep.
> 
> >> +		goto err_free_txport;
> >> +	}
> > 
> > ...
> > 
> >> +	if (ret != 1) {
> >> +		dev_err(dev,
> >> +			"tx%u: 'link-frequencies' must contain a single frequency: %d\n",
> >> +			nport, ret);
> >> +		goto err_free_txport;
> >> +	}
> > 
> > Shouldn't be here.
> > As Rob Herring told at least once that driver must not replace DT validator.
> 
> Ok. Hmm, looks like link-frequencies is not even in the binding doc. 
> I'll add it.
> 
> > ...
> > 
> >> +	if (priv->tx_data_rate != 1600000000 &&
> >> +	    priv->tx_data_rate != 1200000000 &&
> >> +	    priv->tx_data_rate != 800000000 &&
> >> +	    priv->tx_data_rate != 400000000) {
> >> +		dev_err(dev, "tx%u: invalid 'link-frequencies' value\n", nport);
> >> +		return -EINVAL;
> >> +	}
> > 
> > Ditto.
> 
> Is that an important thing to restrict in the DT? I'd rather handle 
> these in the driver. There may well be HW revisions/versions or tricks 
> not documented in the public docs to use other data rates. And, while 
> this is not quite clear to me, the input refclk might also affect the 
> exact data rate.
> 
> With a quick glance, I don't see any other binding defining the data 
> rates. I didn't see any of them even limiting the number of items.

I don't think link frequencies should be restricted in DT, no. The idea
is that a system integrator should pick link frequencies that match
their requirements, both in terms of bandwidth and in terms of EMC. As
most devices have PLLs, the link frequencies can be chosen more or less
freely within a range (or multiple ranges). Many drivers restrict that
to a set of fixed values, but that's a driver limitation, it doesn't
belong to DT bindings.

> > ...
> > 
> >> +	dev_dbg(dev, "tx%u: nominal data rate: %u", nport, priv->tx_data_rate);
> > 
> > All these kind of debugging are needed for production?
> 
> Production meaning upstream kernel? Hard to say. I find all kinds of 
> debugging prints useful.
> 
> > ...
> > 
> >> +static void ub960_csi_handle_events(struct ub960_data *priv, u8 nport)
> >> +{
> >> +	struct device *dev = &priv->client->dev;
> >> +	u8 csi_tx_isr;
> >> +	int ret;
> > 
> >> +	ret = ub960_csiport_read(priv, nport, UB960_TR_CSI_TX_ISR, &csi_tx_isr);
> >> +
> > 
> > Redundant blank line.
> 
> Yep.
> 
> >> +	if (!ret) {
> > 
> > What's wrong with the positive and traditional check, i.e.
> > 
> > 	if (ret)
> > 		return;
> > 
> > ?
> 
> Nothing, just a different style. I can change it.
> 
> >> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR)
> >> +			dev_warn(dev, "TX%u: CSI_SYNC_ERROR\n", nport);
> >> +
> >> +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR)
> >> +			dev_warn(dev, "TX%u: CSI_PASS_ERROR\n", nport);
> >> +	}
> >> +}
> > 
> > ...
> > 
> >> +/* -----------------------------------------------------------------------------
> >> + * RX ports
> >> + */
> > 
> > Multi-line comment is not in the style.
> 
> True. Interesting that checkpatch didn't complain.

This kind of section header is widely used in V4L2, if checkpatch
doesn't complain, let's keep it.

> > ...
> > 
> >> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> > 
> > Post-increment is good enough, no? Ditto for other places.
> 
> Sure. Pre-increment is good enough too, right? It's a simpler operation, 
> although obviously they both compile into the same code. I usually use 
> pre-increment when there's no particular reason to pick either one, 
> although it also depends on how it looks.
> 
> > Esp. taking into account that some of them are using actually
> > post-inc. Why this difference?
> 
> Possibly a different person has written that particular piece of code, 
> or maybe a copy paste from somewhere.
> 
> I'm personally fine with seeing both post and pre increments in code.

They can make a difference in C++ (although compilers should in many
cases optimize that out), which I think is why pre-increment is often
used for loop iterators, and that habbit has just expanded to C code. I
don't mind either way in C.

> >> +		struct ub960_rxport *rxport = priv->rxports[nport];
> >> +
> >> +		if (!rxport || !rxport->vpoc)
> >> +			continue;
> >> +
> >> +		ret = regulator_enable(rxport->vpoc);
> >> +		if (ret)
> >> +			goto err_disable_vpocs;
> >> +	}
> > 
> > ...
> > 
> >> +err_disable_vpocs:
> >> +	for (; nport > 0; --nport) {
> > 
> > 	while (nport--) {
> 
> Yes, that's better.

It's not equivalent though :-) You'll need to replace nport - 1 with
nport on the next line.

> >> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
> >> +
> >> +		if (!rxport || !rxport->vpoc)
> >> +			continue;
> >> +
> >> +		regulator_disable(rxport->vpoc);
> >> +	}
> > 
> > ...
> > 
> >> +	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
> >> +		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
> >> +		return;
> > 
> > Always be careful about WARN*() APIs because with a little trick they may
> > become equivalent to BUG() which is a beast that nobody likes. I.o.w.
> > you have to have justify why this is needed and can't be replaced with
> > dev_*() or analogue.
> > 
> > Same for the other places with WARN*().
> 
> Valid point. I think most of them here are in cases that really 
> shouldn't happen. But if they do happen, I'd like to see a big loud 
> shout about it. The above is not a best example of this, and I think I 
> can just drop the above warns, but, e.g. handling the default case for 
> "switch (rxport->rx_mode)" (which shouldn't happen), I'd prefer to have 
> a big yell in place rather than return silently or print a "normal" 
> error print.
> 
> Obviously WARN is not a good one if it can be toggled to become a BUG.
> 
> So... I think I'll just drop most of them and probably convert the rest 
> (two, actually) to dev_errs.
> 
> > ...
> > 
> >> +	if (strobe_pos < -7)
> >> +		clk_delay = abs(strobe_pos) - 6;
> >> +	else if (strobe_pos > 7)
> >> +		data_delay = strobe_pos - 6;
> >> +	else if (strobe_pos < 0)
> >> +		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
> >> +	else if (strobe_pos > 0)
> >> +		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
> > 
> > I'm wondering if clamp_t()/clamp_val() can be utilised here... And maybe in other
> > places in the driver.
> 
> Hmm, I'm not sure how.
> 
> > ...
> > 
> >> +	ub960_write(priv, UB960_XR_SFILTER_CFG,
> > 
> >> +		    ((u8)strobe_min << UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT) |
> >> +		    ((u8)strobe_max << UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT));
> > 
> > Why castings are needed?
> 
> I don't think they strictly are, but it highlights that the variables, 
> which are signed, are now >= 0, and are used as unsigned.
> 
> > ...
> > 
> >> +	*eq_level = (v & 0x7) + ((v >> 3) & 0x7);
> > 
> > GENMASK()?
> 
> I'll add defines for these bit fields.
> 
> >> +	if (eq_level <= 7) {
> >> +		eq_stage_1_select_value = eq_level;
> >> +		eq_stage_2_select_value = 0;
> >> +	} else {
> >> +		eq_stage_1_select_value = 7;
> >> +		eq_stage_2_select_value = eq_level - 7;
> > 
> > A lot of magic 7 in the code. Are they all of the same semantic? Are they can
> > be converted to use a macro (including respective MIN/MAX macros)?
> 
> It's related to how the value has to be encoded into the register. We 
> keep the equalization level in a simple variable, but need to write it 
> like this into the register. I'm not sure what I would call the magic 7 
> here.
> 
> Then for the strobe position, we use a logical signed value between -7 
> and 7, so we have to +7 when writing that to a register. Except when 
> using a manual strobe position, where the range is -13 to 13 (7+6, 
> that's the 6 in ub960_rxport_set_strobe_pos()).
> 
> It's rather confusing, in my opinion, but I think defines may just make 
> this more confusing. The magic numbers used should always be very close 
> to the registers in question, so if you know how the HW works wrt. 
> strobe & eq, they should be "clear". I'll try to come up with defines 
> that make this clearer, but no promises.
> 
> > ...
> > 
> >> +	WARN_ON(eq_stage_1_select_value > 7);
> >> +	WARN_ON(eq_stage_2_select_value > 7);
> > 
> > Why WARN()?
> 
> I'll drop. I think these were development time helpers long time back.
> 
> > ...
> > 
> >> +	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
> >> +
> >> +	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> >> +	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
> >> +	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
> >> +	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
> >> +	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
> >> +
> >> +	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);
> > 
> > Can't you provide ub960_rxport_update_bits() ?
> 
> I could, but I think it's worse:
> 
> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> 		UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
> 		UB960_RR_AEQ_BYPASS_ENABLE,
> 	(eq_stage_1_select_value
> 	 << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
> 		(eq_stage_2_select_value
> 		 << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
> 		UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
> );
> 
> Indenting it differently, I think it's still worse:
> 
> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
> 	UB960_RR_AEQ_BYPASS_ENABLE,
> 	(eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
> 	(eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
> 	UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
> );

/me fetches the sickness bag :-)

> > ...
> > 
> >> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
> >> +	if (ret)
> >> +		return ret;
> > 
> > Can this be read at once as BE16/LE16 value?
> > Or if the stream of bytes, you can use le/be16_to_cpu().
> 
> I'm not sure, possibly. But is it worth it? I'd need to add new helper 
> functions to read such a value.

It would be nice if regmap provided a way to encode the register size in
the address. Look at the drivers/media/i2c/st-vgxy61.c driver for
instance, which has

#define VGXY61_REG_8BIT(n)                              ((1 << 16) | (n))
#define VGXY61_REG_16BIT(n)                             ((2 << 16) | (n))
#define VGXY61_REG_32BIT(n)                             ((4 << 16) | (n))
#define VGXY61_REG_SIZE_SHIFT                           16
#define VGXY61_REG_ADDR_MASK                            0xffff

#define VGXY61_REG_MODEL_ID                             VGXY61_REG_16BIT(0x0000)
...

	id = vgxy61_read_reg(sensor, VGXY61_REG_MODEL_ID);


The vgxy61_read_reg() and vgxy61_write_reg() functions then extract the
size from the register address argument, and issue multi-byte I2C
reads/writes as necessary. It makes it really nice for drivers, as you
don't have to deal with multi-byte access manually anymore. Other
drivers, like imx219.c for instance, pass the size as an explicit
argument to the read/write functions, but that's error-prone.

> >> +	parity_errors = (v1 << 8) | v2;
> > 
> > ...
> > 
> >> +	errors = (rx_port_sts1 & 0x2c) || (rx_port_sts2 & 0x20) ||
> >> +		 (bcc_sts & 0x3f) || (csi_rx_sts & 0xf) || csi_err_cnt ||
> > 
> > BIT()? GENMASK()?
> 
> I'll add defines for the error masks (those are bit masks of error bits 
> in the registers).
> 
> > At bare minimum this needs a good comment to explain all these magics.
> > 
> >> +		 parity_errors;
> > 
> > ...
> > 
> >> +	*ok = !errors;
> > 
> > How this is different to the something like returning 1 here (and 0 above)?
> > You may save some code by dropping redundant parameter.
> 
> Return value 1 means there was an error when reading the register 
> values. 0 means we read the values, and "ok" contains a summary (ok or 
> not) of the link's status.
> 
> >> +	return 0;
> > 
> > ...
> > 
> >> +	while (time_before(jiffies, timeout)) {
> >> +		missing = 0;
> >> +
> >> +		for_each_set_bit(nport, &port_mask,
> >> +				 priv->hw_data->num_rxports) {
> >> +			struct ub960_rxport *rxport = priv->rxports[nport];
> >> +			bool ok;
> >> +
> >> +			if (!rxport)
> >> +				continue;
> >> +
> >> +			ret = ub960_rxport_link_ok(priv, nport, &ok);
> >> +			if (ret)
> >> +				return ret;
> >> +
> >> +			if (!ok || !(link_ok_mask & BIT(nport)))
> >> +				missing++;
> >> +
> >> +			if (ok)
> >> +				link_ok_mask |= BIT(nport);
> >> +			else
> >> +				link_ok_mask &= ~BIT(nport);
> >> +		}
> >> +
> >> +		loops++;
> >> +
> >> +		if (missing == 0)
> >> +			break;
> >> +
> >> +		msleep(50);
> >> +	}
> > 
> > You can wrap the body into readx_poll_timeout() from iopoll.h.
> 
> Hmm... How would I do that? With some kind of helper structs to wrap the 
> input and output parameters? Sounds very messy, but maybe I'm missing 
> something.
> 
> > ...
> > 
> >> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
> >> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
> > 
> > Same Q, can these be unified to some kind of bulk read?
> 
> Perhaps, but again, I don't see the value for creating a bulk read 
> helper function for these few cases.
> 
> > ...
> > 
> >> +		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
> >> +			nport, strobe_pos, eq_level,
> >> +			v1 * 1000000 + v2 * 1000000 / 256);
> > 
> > Even this will be simpler with above suggestion.
> 
> Hmm... How is that?
> 
> > ...
> > 
> >> +static int ub960_rxport_add_serializers(struct ub960_data *priv)
> >> +{
> >> +	unsigned int nport;
> >> +	int ret;
> >> +
> >> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> > 
> > Post-inc?
> 
> I still like pre-inc =).
> 
> I see there's a mix os post and pre incs in the code. I'll align those 
> when I encounter them, but I don't think it's worth the effort to 
> methodically go through all of them to change them use the same style.
> 
> >> +		struct ub960_rxport *rxport = priv->rxports[nport];
> >> +
> >> +		if (!rxport)
> >> +			continue;
> >> +
> >> +		ret = ub960_rxport_add_serializer(priv, nport);
> >> +		if (ret)
> >> +			goto err_remove_sers;
> >> +	}
> >> +
> >> +	return 0;
> >> +
> >> +err_remove_sers:
> >> +	for (; nport > 0; --nport) {
> > 
> > 	while(nport--)
> > 
> > (and drop those -1:s below)
> 
> Yes, that cleans this up nicely.
> 
> >> +		struct ub960_rxport *rxport = priv->rxports[nport - 1];
> >> +
> >> +		if (!rxport)
> >> +			continue;
> >> +
> >> +		rxport = priv->rxports[nport - 1];
> >> +		if (!rxport)
> >> +			continue;
> >> +
> >> +		ub960_rxport_remove_serializer(priv, nport - 1);
> >> +	}
> >> +
> >> +	return ret;
> >> +}
> > 
> > ...
> > 
> >> +	if (priv->tx_data_rate == 1600000000)
> > 
> > Easy to make a mistake, perhaps something from units.h / time.h can be used?
> 
> Hmm, time.h? What's in there.
> 
> I don't like the HZ_PER_MHZ too much. But I'll add this, which I 
> recently added to a Renesas driver:
> 
> #define MHZ(v) ((u32)((v) * 1000000U))
> 
> I like it, as e.g. MHZ(1.6) works and (I think) is quite clear. Here 
> it's MHZ(1600), of course.

C++ user-defined literals anyone, to write 1600_mHz and get the compiler
to do the magic ? ;-)

> >> +		csi_ctl |= UB960_TR_CSI_CTL_CSI_CAL_EN;
> > 
> > ...
> > 
> >> +	switch (priv->tx_data_rate) {
> >> +	case 1600000000:
> >> +	default:
> >> +		speed_select = 0;
> >> +		pll_div = 0x10;
> >> +		break;
> >> +	case 1200000000:
> >> +		speed_select = 1;
> >> +		break;
> >> +	case 800000000:
> >> +		speed_select = 2;
> >> +		pll_div = 0x10;
> >> +		break;
> >> +	case 400000000:
> >> +		speed_select = 3;
> >> +		pll_div = 0x10;
> >> +		break;
> >> +	}
> > 
> > Ditto, but maybe defines for them?
> > 
> > ...
> > 
> >> +	switch (rxport->rx_mode) {
> >> +	default:
> >> +		WARN_ON(true);
> >> +		fallthrough;
> > 
> > Maybe you can drop default completely and rely on compiler to produce a
> > warning?
> 
> I've dropped the default, but I had to add cases for the RAW12 modes 
> (which are not supported at the moment).
> 
> >> +	case RXPORT_MODE_RAW10:
> >> +		/*
> >> +		 * RAW10_8BIT_CTL = 0b11 : 8-bit processing using lower 8 bits
> >> +		 * 0b10 : 8-bit processing using upper 8 bits
> >> +		 */
> >> +		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2,
> >> +					 0x3 << 6, 0x2 << 6);
> >> +
> >> +		break;
> >> +
> >> +	case RXPORT_MODE_CSI2_SYNC:
> >> +	case RXPORT_MODE_CSI2_ASYNC:
> >> +
> >> +		break;
> >> +	}
> > 
> > ...
> > 
> >> +	u8 cur_vc[UB960_MAX_TX_NPORTS] = { 0 };
> > 
> > 0 is not needed.
> 
> Yep.
> 
> > ...
> > 
> >> +	for (i = 0; i < routing->num_routes; ++i) {
> >> +		struct v4l2_subdev_route *route = &routing->routes[i];
> >> +		unsigned int rx, tx;
> >> +
> >> +		rx = ub960_pad_to_port(priv, route->sink_pad);
> > 
> >> +
> > 
> > Redundant blank line.
> 
> Yep.
> 
> >> +		if (BIT(rx) & handled_mask)
> >> +			continue;
> >> +
> >> +		tx = ub960_pad_to_port(priv, route->source_pad);
> >> +
> >> +		vc[rx] = cur_vc[tx]++;
> >> +		handled_mask |= BIT(rx);
> >> +	}
> > 
> > ...
> > 
> >> +		if (rx_data[nport].tx_port == 1)
> >> +			fwd_ctl |= BIT(nport); /* forward to TX1 */
> >> +		else
> >> +			fwd_ctl &= ~BIT(nport); /* forward to TX0 */
> > 
> > This and many other similar places can be replaced by __assign_bit()
> > if the lvalue is type of unsigned long or can be made that type.
> 
> It is u8, as it is written to a 8 bit register. It could be made 
> unsigned long, but... I'd rather use u8 when we are dealing with 8 bits 
> of data.
> 
> > ...
> > 
> >> +static void ub960_update_streaming_status(struct ub960_data *priv)
> >> +{
> >> +	unsigned int i;
> > 
> >> +	bool streaming = false;
> > 
> > Redundant
> > >> +	for (i = 0; i < UB960_MAX_NPORTS; ++i) {
> >> +		if (priv->stream_enable_mask[i]) {
> >> +			streaming = true;
> >> +			break;
> >> +		}
> >> +	}
> > 
> >> +	priv->streaming = streaming;
> > 
> > 	priv->streaming = i < UB960_MAX_NPORTS;
> 
> Yes, that's a bit simpler.
> 
> >> +}
> > 
> > ...
> > 
> >> +				for (; nport > 0; --nport) {
> > 
> > 				while (nport--)
> 
> Yep.
> 
> >> +					if (pad_stream_masks[nport - 1] == 0)
> >> +						continue;
> >> +
> >> +					ub960_disable_streams(
> >> +						sd, state,
> >> +						priv->hw_data->num_rxports +
> >> +							nport - 1,
> >> +						pad_stream_masks[nport - 1]);
> >> +				}
> > 
> > ...
> > 
> >> +	char id[7];
> > 
> > u8?
> > 
> >> +	for (unsigned int i = 0; i < 6; ++i)
> >> +		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
> >> +	id[6] = 0;
> > 
> > If it's only for printing, the 0 is not needed...
> > 
> >> +	dev_info(dev, "ID '%s'\n", id);
> > 
> > ...as you may put it as
> > 
> > 	dev_info(dev, "ID: '%.*s'\n", (int)sizeof(id), id);
> > 
> > (I wrote from the top of my head, maybe not compilable as is).
> 
> And you think that is clearer? =) I have to disagree.
> 
> > ...
> > 
> >> +static irqreturn_t ub960_handle_events(int irq, void *arg)
> >> +{
> >> +	struct ub960_data *priv = arg;
> >> +	unsigned int i;
> >> +	u8 int_sts;
> >> +	int ret;
> > 
> >> +	ret = ub960_read(priv, UB960_SR_INTERRUPT_STS, &int_sts);
> > 
> >> +
> > 
> > Redundant blank line. I guess you may decrease your code by ~2.5% by removing
> > such unneeded blank lines here and there.
> 
> I only found a few of these, which I have fixed.
> 
> >> +	if (!ret && int_sts) {
> > 
> > 	if (ret)
> > 		return ...
> > 
> > 	if (!int_sts)
> > 		return IRQ_NONE; // No?
> 
> Yes, I think that's correct. I wonder what to return in the (ret) case. 
> Probably also IRQ_NONE, as we don't know if the interrupt was for us.
> 
> >> +		u8 fwd_sts;
> >> +
> >> +		dev_dbg(&priv->client->dev, "INTERRUPT_STS %x\n", int_sts);
> >> +
> >> +		ub960_read(priv, UB960_SR_FWD_STS, &fwd_sts);
> >> +
> >> +		dev_dbg(&priv->client->dev, "FWD_STS %#02x\n", fwd_sts);
> >> +
> >> +		for (i = 0; i < priv->hw_data->num_txports; ++i) {
> >> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_CSI_TX(i))
> >> +				ub960_csi_handle_events(priv, i);
> >> +		}
> >> +
> >> +		for (i = 0; i < priv->hw_data->num_rxports; i++) {
> >> +			if (!priv->rxports[i])
> >> +				continue;
> >> +
> >> +			if (int_sts & UB960_SR_INTERRUPT_STS_IS_RX(i))
> >> +				ub960_rxport_handle_events(priv, i);
> >> +		}
> >> +	}
> > 
> >> +	return IRQ_HANDLED;
> >> +}
> > 
> > ...
> > 
> >> +	if (cdr_mode > RXPORT_CDR_LAST) {
> >> +		dev_err(dev, "rx%u: bad 'ti,cdr-mode' %u\n", nport, cdr_mode);
> >> +		return -EINVAL;
> >> +	}
> > 
> > No DT validation if it's not used in (memory) allocation.
> 
> I'm not quite fine with dropping all these DT checks. If the user 
> happens to provide a DT with illegal values, the end results can be odd 
> and the reason quite difficult to figure out. Isn't it much better to 
> have a few extra checks in the driver?
> 
> > ...
> > 
> >> +	ret = fwnode_property_read_u32(link_fwnode, "ti,strobe-pos",
> >> +				       &strobe_pos);
> >> +	if (ret) {
> >> +		if (ret != -EINVAL) {
> >> +			dev_err(dev,
> >> +				"rx%u: failed to read 'ti,strobe-pos': %d\n",
> >> +				nport, ret);
> >> +			return ret;
> >> +		}
> >> +	} else if (strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
> >> +		   strobe_pos > UB960_MAX_MANUAL_STROBE_POS) {
> >> +		dev_err(dev, "rx%u: illegal 'strobe-pos' value: %d\n", nport,
> >> +			strobe_pos);
> >> +	} else {
> >> +		// NOTE: ignored unless global manual strobe pos is set
> > 
> > Style?
> 
> Oops...
> 
> >> +		rxport->eq.strobe_pos = strobe_pos;
> >> +		if (!priv->strobe.manual)
> >> +			dev_warn(dev,
> >> +				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
> >> +				 nport);
> >> +	}
> > 
> > This and below looks a bit different to the above in the same function. Perhaps
> > these can be refactored to be less LoCs.
> 
> Hmm what did you have in mind?
> 
> >> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> >> +	if (ret) {
> >> +		if (ret != -EINVAL) {
> >> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> >> +				nport, ret);
> >> +			return ret;
> >> +		}
> >> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> >> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> >> +			eq_level);
> >> +	} else {
> >> +		rxport->eq.manual_eq = true;
> >> +		rxport->eq.manual.eq_level = eq_level;
> >> +	}
> >> +
> >> +	ret = fwnode_property_read_u32(link_fwnode, "i2c-alias",
> >> +				       &ser_i2c_alias);
> >> +	if (ret) {
> >> +		dev_err(dev, "rx%u: failed to read 'i2c-alias': %d\n", nport,
> >> +			ret);
> >> +		return ret;
> >> +	}
> > 
> > ...
> > 
> >> +static struct fwnode_handle *
> >> +ub960_fwnode_get_link_by_regs(struct fwnode_handle *links_fwnode,
> >> +			      unsigned int nport)
> >> +{
> >> +	struct fwnode_handle *link_fwnode;
> >> +	int ret;
> >> +
> >> +	fwnode_for_each_child_node(links_fwnode, link_fwnode) {
> >> +		u32 link_num;
> >> +
> >> +		if (strncmp(fwnode_get_name(link_fwnode), "link@", 5) != 0)
> >> +			continue;
> > 
> > str_has_prefix()
> 
> I knew there must be a function for this, but didn't find it =).
> 
> >> +
> >> +		ret = fwnode_property_read_u32(link_fwnode, "reg", &link_num);
> >> +		if (ret)
> > 
> > Refcount imbalance.
> 
> Yep.
> 
> >> +			return NULL;
> >> +
> >> +		if (nport == link_num) {
> >> +			fwnode_handle_put(link_fwnode);
> >> +			return link_fwnode;
> >> +		}
> >> +	}
> >> +
> >> +	return NULL;
> >> +}
> > 
> > ...
> > 
> >> +		asd = v4l2_async_nf_add_fwnode(&priv->notifier,
> >> +					       rxport->source_ep_fwnode,
> >> +					       struct ub960_asd);
> >> +		if (IS_ERR(asd)) {
> >> +			dev_err(dev, "Failed to add subdev for source %u: %ld",
> > 
> > %pe ?
> 
> Yep.
> 
> >> +				i, PTR_ERR(asd));
> >> +			v4l2_async_nf_cleanup(&priv->notifier);
> >> +			return PTR_ERR(asd);
> >> +		}
> > 
> > ...
> > 
> >> +err_pd_gpio:
> >> +	if (priv->pd_gpio)
> > 
> > Dup test.
> 
> What do you mean dup? You mean gpiod_set_value_cansleep can be called 
> with gpio = NULL? The docs don't say this, but I guess that is the case.
> 
> >> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> > 
> > ...
> > 
> >> +	if (priv->pd_gpio)
> >> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> > 
> > Ditto.
> > 
> > ...
> > 
> >> +	priv->hw_data = of_device_get_match_data(dev);
> > 
> > Why of_ out of the blue?!
> 
> Hmm... How do I get the data in a generic way? I'll have to study this a 
> bit.

Possibly device_get_match_data(dev).

While I like genericity, I'd also question why we should introduce the
overhead that goes with it for drivers that will most likely be used on
DT-based systems only.

> >> +	if (!priv->hw_data)
> >> +		return -ENODEV;
> > 
> > ...
> > 
> >> +	priv->current_indirect_target = 0xff;
> >> +	priv->current_read_rxport = 0xff;
> >> +	priv->current_write_rxport_mask = 0xff;
> >> +	priv->current_read_csiport = 0xff;
> >> +	priv->current_write_csiport_mask = 0xff;
> > 
> > GENMASK()
> 
> These are not masks, but invalid values. We set these to an invalid 
> value (0xff) so that when a reg access function next time checks if we 
> are already targeting, e.g. a particular rxport, it will always opt to 
> select the rxport by writing to the approriate registers.
> 
> > ...
> > 
> >> +	ub960_rxport_wait_locks(priv, 0xf, NULL);
> > 
> > Ditto?
> 
> Yep.
> 
> > ...
> > 
> >> +static const struct i2c_device_id ub960_id[] = {
> >> +	{ "ds90ub960-q1", 0 },
> >> +	{ "ds90ub9702-q1", 0 },
> > 
> > Why driver data is different to OF case?
> 
> I have just never used these so I've missed it. As I said, I need to 
> look at this and figure out how to get the data correctly in all the cases.

device_get_match_data() will call of_device_get_match_data() on DT-based
systems, so there's no need to specify anything in the i2c_device_id
entries.

> >> +	{}
> >> +};
> >> +MODULE_DEVICE_TABLE(i2c, ub960_id);
> >> +
> >> +static const struct of_device_id ub960_dt_ids[] = {
> >> +	{ .compatible = "ti,ds90ub960-q1", .data = &ds90ub960_hw },
> >> +	{ .compatible = "ti,ds90ub9702-q1", .data = &ds90ub9702_hw },
> >> +	{}
> >> +};
> >> +MODULE_DEVICE_TABLE(of, ub960_dt_ids);
> > 
> >> +static struct i2c_driver ds90ub960_driver = {
> >> +	.probe_new	= ub960_probe,
> >> +	.remove		= ub960_remove,
> >> +	.id_table	= ub960_id,
> >> +	.driver = {
> >> +		.name	= "ds90ub960",
> > 
> >> +		.owner = THIS_MODULE,
> > 
> > Set by macro from the beginning of its, macro, existence.
> 
> Ok.
> 
> >> +		.of_match_table = ub960_dt_ids,
> >> +	},
> >> +};
> > 
> > ...
> > 
> >> +struct ds90ub9xx_platform_data {
> >> +	u32 port;
> >> +	struct i2c_atr *atr;
> >> +	unsigned long bc_rate;
> > 
> > Not sure why we need this to be public except, probably, atr...
> 
> The port and atr are used by the serializers, for atr. The bc_rate is 
> used by the serializers to figure out the clocking (they may use the 
> FPD-Link's frequency internally).
Andy Shevchenko Jan. 20, 2023, 4:47 p.m. UTC | #4
On Thu, Jan 19, 2023 at 06:27:31PM +0200, Tomi Valkeinen wrote:
> On 18/01/2023 17:48, Andy Shevchenko wrote:
> > On Wed, Jan 18, 2023 at 02:40:29PM +0200, Tomi Valkeinen wrote:
> > > Add driver for TI DS90UB960 FPD-Link III Deserializer.

...

> > > +#define UB960_MIN_AEQ_STROBE_POS -7
> > 
> > I believe it might need parentheses due to theoretical possibilities to be used
> > in the expression.
> 
> Hmm, for my education, in which kind of expressions this could cause an
> issue?

To mine as well, surprised by 'foo = foo - - - -7;' being compilable.
But according to the Operator Precedence it's fine.

...

> Is that an important thing to restrict in the DT?

I believe so. It's a part of the idea behind YAML schema to make it possible
to validate for all possible scenarios. AFAIU that's how they can actually
see if firmware doesn't have any bugs in the description (read: DT).

> I'd rather handle these in
> the driver. There may well be HW revisions/versions or tricks not documented
> in the public docs to use other data rates. And, while this is not quite
> clear to me, the input refclk might also affect the exact data rate.
> 
> With a quick glance, I don't see any other binding defining the data rates.
> I didn't see any of them even limiting the number of items.

Then I suggest to have Rob's Ack on this. If he is fine, I'll keep that
in mind.

...

> > > +	if (!ret) {
> > 
> > What's wrong with the positive and traditional check, i.e.
> > 
> > 	if (ret)
> > 		return;
> > 
> > ?
> 
> Nothing, just a different style. I can change it.

The benefit is a decreased level of the indentation.

> > > +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR)
> > > +			dev_warn(dev, "TX%u: CSI_SYNC_ERROR\n", nport);
> > > +
> > > +		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR)
> > > +			dev_warn(dev, "TX%u: CSI_PASS_ERROR\n", nport);
> > > +	}

...

> > > +/* -----------------------------------------------------------------------------
> > > + * RX ports
> > > + */
> > 
> > Multi-line comment is not in the style.
> 
> True. Interesting that checkpatch didn't complain.

Because this format is the official for net subsystem.

...

> > > +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> > 
> > Post-increment is good enough, no? Ditto for other places.
> 
> Sure. Pre-increment is good enough too, right? It's a simpler operation,
> although obviously they both compile into the same code. I usually use
> pre-increment when there's no particular reason to pick either one, although
> it also depends on how it looks.

Then be consistent, use it everywhere.

> > Esp. taking into account that some of them are using actually
> > post-inc. Why this difference?
> 
> Possibly a different person has written that particular piece of code, or
> maybe a copy paste from somewhere.
> 
> I'm personally fine with seeing both post and pre increments in code.

I'm not :-), if it's not required by the code. Pre-increment always puzzles
me: Is here anything I have to pay an additional attention to?

> > > +		struct ub960_rxport *rxport = priv->rxports[nport];
> > > +
> > > +		if (!rxport || !rxport->vpoc)
> > > +			continue;
> > > +
> > > +		ret = regulator_enable(rxport->vpoc);
> > > +		if (ret)
> > > +			goto err_disable_vpocs;
> > > +	}

...

> > > +	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
> > > +		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
> > > +		return;
> > 
> > Always be careful about WARN*() APIs because with a little trick they may
> > become equivalent to BUG() which is a beast that nobody likes. I.o.w.
> > you have to have justify why this is needed and can't be replaced with
> > dev_*() or analogue.
> > 
> > Same for the other places with WARN*().
> 
> Valid point. I think most of them here are in cases that really shouldn't
> happen. But if they do happen, I'd like to see a big loud shout about it.

...if you have time to catch it. Read about "panic_on_warn".

> The above is not a best example of this, and I think I can just drop the
> above warns, but, e.g. handling the default case for "switch
> (rxport->rx_mode)" (which shouldn't happen), I'd prefer to have a big yell
> in place rather than return silently or print a "normal" error print.
> 
> Obviously WARN is not a good one if it can be toggled to become a BUG.
> 
> So... I think I'll just drop most of them and probably convert the rest
> (two, actually) to dev_errs.

...

> > > +	if (strobe_pos < -7)
> > > +		clk_delay = abs(strobe_pos) - 6;
> > > +	else if (strobe_pos > 7)
> > > +		data_delay = strobe_pos - 6;
> > > +	else if (strobe_pos < 0)
> > > +		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
> > > +	else if (strobe_pos > 0)
> > > +		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
> > 
> > I'm wondering if clamp_t()/clamp_val() can be utilised here... And maybe in other
> > places in the driver.
> 
> Hmm, I'm not sure how.

I can't suggest you, because it's magic to me what is going on, e.g. for
the strobe_pos < -7 case, and why abs(strobe_pos) - 6 wouldn't overflow
the bit field or whatever that uses it.

...

> > > +	if (eq_level <= 7) {
> > > +		eq_stage_1_select_value = eq_level;
> > > +		eq_stage_2_select_value = 0;
> > > +	} else {
> > > +		eq_stage_1_select_value = 7;
> > > +		eq_stage_2_select_value = eq_level - 7;
> > 
> > A lot of magic 7 in the code. Are they all of the same semantic? Are they can
> > be converted to use a macro (including respective MIN/MAX macros)?
> 
> It's related to how the value has to be encoded into the register. We keep
> the equalization level in a simple variable, but need to write it like this
> into the register. I'm not sure what I would call the magic 7 here.
> 
> Then for the strobe position, we use a logical signed value between -7 and
> 7, so we have to +7 when writing that to a register. Except when using a
> manual strobe position, where the range is -13 to 13 (7+6, that's the 6 in
> ub960_rxport_set_strobe_pos()).
> 
> It's rather confusing, in my opinion, but I think defines may just make this
> more confusing. The magic numbers used should always be very close to the
> registers in question, so if you know how the HW works wrt. strobe & eq,
> they should be "clear". I'll try to come up with defines that make this
> clearer, but no promises.

Obviously I disagree on the fact that it's more confusing. Consider that 7
and 7. How do I know that their semantics is the same or different? With
the name assigned it's differentiated by the name used.

...

> > > +	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
> > > +
> > > +	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> > > +	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
> > > +	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
> > > +	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
> > > +	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
> > > +
> > > +	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);
> > 
> > Can't you provide ub960_rxport_update_bits() ?
> 
> I could, but I think it's worse:
> 
> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> 		UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
> 		UB960_RR_AEQ_BYPASS_ENABLE,
> 	(eq_stage_1_select_value
> 	 << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
> 		(eq_stage_2_select_value
> 		 << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
> 		UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
> );
> 
> Indenting it differently, I think it's still worse:
> 
> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
> 	UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
> 	UB960_RR_AEQ_BYPASS_ENABLE,
> 	(eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
> 	(eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
> 	UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
> );

You can always use temporary variables to make code better to read.
But it's up to you. Usually the R-M-W <--> vs. U is about locking or
serialisation and handling it in a separate code is better.

...

> > > +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
> > > +	if (ret)
> > > +		return ret;
> > 
> > Can this be read at once as BE16/LE16 value?
> > Or if the stream of bytes, you can use le/be16_to_cpu().
> 
> I'm not sure, possibly. But is it worth it? I'd need to add new helper
> functions to read such a value.

I think it worth it to show exactly what is provided by the hardware
and how we handle it (endianess wise).

> > > +	parity_errors = (v1 << 8) | v2;

...

> > > +	*ok = !errors;
> > 
> > How this is different to the something like returning 1 here (and 0 above)?
> > You may save some code by dropping redundant parameter.
> 
> Return value 1 means there was an error when reading the register values. 0
> means we read the values, and "ok" contains a summary (ok or not) of the
> link's status.

I was expecting that error is negative, no?

> > > +	return 0;

...

> > > +	while (time_before(jiffies, timeout)) {
> > > +		missing = 0;
> > > +
> > > +		for_each_set_bit(nport, &port_mask,
> > > +				 priv->hw_data->num_rxports) {
> > > +			struct ub960_rxport *rxport = priv->rxports[nport];
> > > +			bool ok;
> > > +
> > > +			if (!rxport)
> > > +				continue;
> > > +
> > > +			ret = ub960_rxport_link_ok(priv, nport, &ok);
> > > +			if (ret)
> > > +				return ret;
> > > +
> > > +			if (!ok || !(link_ok_mask & BIT(nport)))
> > > +				missing++;
> > > +
> > > +			if (ok)
> > > +				link_ok_mask |= BIT(nport);
> > > +			else
> > > +				link_ok_mask &= ~BIT(nport);
> > > +		}
> > > +
> > > +		loops++;
> > > +
> > > +		if (missing == 0)
> > > +			break;
> > > +
> > > +		msleep(50);
> > > +	}
> > 
> > You can wrap the body into readx_poll_timeout() from iopoll.h.
> 
> Hmm... How would I do that? With some kind of helper structs to wrap the
> input and output parameters? Sounds very messy, but maybe I'm missing
> something.

It's me who added extra 'x', what I meant is read_poll_timeout(). It
accepts variadic arguments, i.o.w. any function with any arguments can
be provided.

...

> > > +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
> > > +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
> > 
> > Same Q, can these be unified to some kind of bulk read?
> 
> Perhaps, but again, I don't see the value for creating a bulk read helper
> function for these few cases.

OK.

...

> > > +		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
> > > +			nport, strobe_pos, eq_level,
> > > +			v1 * 1000000 + v2 * 1000000 / 256);
> > 
> > Even this will be simpler with above suggestion.
> 
> Hmm... How is that?

		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
			nport, strobe_pos, eq_level, v * 1000000 / 256);

See?

...

> > > +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> > 
> > Post-inc?
> 
> I still like pre-inc =).
> 
> I see there's a mix os post and pre incs in the code. I'll align those when
> I encounter them, but I don't think it's worth the effort to methodically go
> through all of them to change them use the same style.

Kernel uses post-inc is an idiom for loops:

$ git grep -n -w '[_a-z0-9]\+++' | wc -l
148693

$ git grep -n -w ' ++[a-z0-9_]\+' | wc -l
8701

So, non-standard pattern needs to be explained.

> > > +	}

...

> > > +	for (unsigned int i = 0; i < 6; ++i)
> > > +		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
> > > +	id[6] = 0;
> > 
> > If it's only for printing, the 0 is not needed...
> > 
> > > +	dev_info(dev, "ID '%s'\n", id);
> > 
> > ...as you may put it as
> > 
> > 	dev_info(dev, "ID: '%.*s'\n", (int)sizeof(id), id);
> > 
> > (I wrote from the top of my head, maybe not compilable as is).
> 
> And you think that is clearer? =)

To me, yes. Maybe because I'm familiar with that.

> I have to disagree.

Your right :-)

...

> I'm not quite fine with dropping all these DT checks. If the user happens to
> provide a DT with illegal values, the end results can be odd and the reason
> quite difficult to figure out. Isn't it much better to have a few extra
> checks in the driver?

As I said above, ask Rob, if he is fine with that I will have no objections.

...

> > > +		rxport->eq.strobe_pos = strobe_pos;
> > > +		if (!priv->strobe.manual)
> > > +			dev_warn(dev,
> > > +				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
> > > +				 nport);
> > > +	}
> > 
> > This and below looks a bit different to the above in the same function. Perhaps
> > these can be refactored to be less LoCs.
> 
> Hmm what did you have in mind?
> 
> > > +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> > > +	if (ret) {
> > > +		if (ret != -EINVAL) {
> > > +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> > > +				nport, ret);
> > > +			return ret;
> > > +		}

This seems like trying to handle special cases, if you want it to be optional,
why not ignoring all errors?

> > > +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> > > +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> > > +			eq_level);

This part is a validation of DT again, but we discussed above this.

> > > +	} else {
> > > +		rxport->eq.manual_eq = true;
> > > +		rxport->eq.manual.eq_level = eq_level;
> > > +	}

...

> > > +err_pd_gpio:
> > > +	if (priv->pd_gpio)
> > 
> > Dup test.
> 
> What do you mean dup? You mean gpiod_set_value_cansleep can be called with
> gpio = NULL? The docs don't say this, but I guess that is the case.

Yes. This is the idea of having _optional() GPIO APIs.

> > > +		gpiod_set_value_cansleep(priv->pd_gpio, 1);

...

> > > +	if (priv->pd_gpio)
> > > +		gpiod_set_value_cansleep(priv->pd_gpio, 1);

Ditto.

...

> > > +	priv->hw_data = of_device_get_match_data(dev);
> > 
> > Why of_ out of the blue?!
> 
> Hmm... How do I get the data in a generic way? I'll have to study this a
> bit.

Just drop of_ :-)

	priv->hw_data = device_get_match_data(dev);

> > > +	if (!priv->hw_data)
> > > +		return -ENODEV;

...

> > > +	priv->current_indirect_target = 0xff;
> > > +	priv->current_read_rxport = 0xff;
> > > +	priv->current_write_rxport_mask = 0xff;
> > > +	priv->current_read_csiport = 0xff;
> > > +	priv->current_write_csiport_mask = 0xff;
> > 
> > GENMASK()
> 
> These are not masks, but invalid values. We set these to an invalid value
> (0xff) so that when a reg access function next time checks if we are already
> targeting, e.g. a particular rxport, it will always opt to select the rxport
> by writing to the approriate registers.

Then define with respective name?

...

> > > +struct ds90ub9xx_platform_data {
> > > +	u32 port;
> > > +	struct i2c_atr *atr;
> > > +	unsigned long bc_rate;
> > 
> > Not sure why we need this to be public except, probably, atr...
> 
> The port and atr are used by the serializers, for atr. The bc_rate is used
> by the serializers to figure out the clocking (they may use the FPD-Link's
> frequency internally).

The plain numbers can be passed as device properties. That's why the question
about platform data. Platform data in general is discouraged to be used in a
new code.
Tomi Valkeinen Jan. 25, 2023, 11:15 a.m. UTC | #5
Hi Andy,

On 20/01/2023 18:47, Andy Shevchenko wrote:

>>> Esp. taking into account that some of them are using actually
>>> post-inc. Why this difference?
>>
>> Possibly a different person has written that particular piece of code, or
>> maybe a copy paste from somewhere.
>>
>> I'm personally fine with seeing both post and pre increments in code.
> 
> I'm not :-), if it's not required by the code. Pre-increment always puzzles
> me: Is here anything I have to pay an additional attention to?

That is interesting, as to me pre-increment is the simpler, more obvious 
case. It's just:

v = v + 1
v

Whereas post-increment is:

temp = v
v = v + 1
temp

In any case, we're side-tracking here, I think =).

>>>> +		struct ub960_rxport *rxport = priv->rxports[nport];
>>>> +
>>>> +		if (!rxport || !rxport->vpoc)
>>>> +			continue;
>>>> +
>>>> +		ret = regulator_enable(rxport->vpoc);
>>>> +		if (ret)
>>>> +			goto err_disable_vpocs;
>>>> +	}
> 
> ...
> 
>>>> +	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
>>>> +		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
>>>> +		return;
>>>
>>> Always be careful about WARN*() APIs because with a little trick they may
>>> become equivalent to BUG() which is a beast that nobody likes. I.o.w.
>>> you have to have justify why this is needed and can't be replaced with
>>> dev_*() or analogue.
>>>
>>> Same for the other places with WARN*().
>>
>> Valid point. I think most of them here are in cases that really shouldn't
>> happen. But if they do happen, I'd like to see a big loud shout about it.
> 
> ...if you have time to catch it. Read about "panic_on_warn".

Reading about WARNs on coding-style.rst, it very much sounds like the 
WARNs in the driver were fine: they were in places that are never 
supposed to happen. However, I have already dropped them, and I'm fine 
keeping it that way.

>> The above is not a best example of this, and I think I can just drop the
>> above warns, but, e.g. handling the default case for "switch
>> (rxport->rx_mode)" (which shouldn't happen), I'd prefer to have a big yell
>> in place rather than return silently or print a "normal" error print.
>>
>> Obviously WARN is not a good one if it can be toggled to become a BUG.
>>
>> So... I think I'll just drop most of them and probably convert the rest
>> (two, actually) to dev_errs.
> 
> ...
> 
>>>> +	if (strobe_pos < -7)
>>>> +		clk_delay = abs(strobe_pos) - 6;
>>>> +	else if (strobe_pos > 7)
>>>> +		data_delay = strobe_pos - 6;
>>>> +	else if (strobe_pos < 0)
>>>> +		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
>>>> +	else if (strobe_pos > 0)
>>>> +		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
>>>
>>> I'm wondering if clamp_t()/clamp_val() can be utilised here... And maybe in other
>>> places in the driver.
>>
>> Hmm, I'm not sure how.
> 
> I can't suggest you, because it's magic to me what is going on, e.g. for
> the strobe_pos < -7 case, and why abs(strobe_pos) - 6 wouldn't overflow
> the bit field or whatever that uses it.

Ah, I see, you were thinking of ensuring the input parameters are in 
range. I thought you meant to somehow optimize the "algorithm" above 
with clamps.

I don't think clamps are needed, the input parameters should always be 
in range, as they are validated when reading the DT.

> ...
> 
>>>> +	if (eq_level <= 7) {
>>>> +		eq_stage_1_select_value = eq_level;
>>>> +		eq_stage_2_select_value = 0;
>>>> +	} else {
>>>> +		eq_stage_1_select_value = 7;
>>>> +		eq_stage_2_select_value = eq_level - 7;
>>>
>>> A lot of magic 7 in the code. Are they all of the same semantic? Are they can
>>> be converted to use a macro (including respective MIN/MAX macros)?
>>
>> It's related to how the value has to be encoded into the register. We keep
>> the equalization level in a simple variable, but need to write it like this
>> into the register. I'm not sure what I would call the magic 7 here.
>>
>> Then for the strobe position, we use a logical signed value between -7 and
>> 7, so we have to +7 when writing that to a register. Except when using a
>> manual strobe position, where the range is -13 to 13 (7+6, that's the 6 in
>> ub960_rxport_set_strobe_pos()).
>>
>> It's rather confusing, in my opinion, but I think defines may just make this
>> more confusing. The magic numbers used should always be very close to the
>> registers in question, so if you know how the HW works wrt. strobe & eq,
>> they should be "clear". I'll try to come up with defines that make this
>> clearer, but no promises.
> 
> Obviously I disagree on the fact that it's more confusing. Consider that 7
> and 7. How do I know that their semantics is the same or different? With
> the name assigned it's differentiated by the name used.

I have added defines for these now.

> ...
> 
>>>> +	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
>>>> +
>>>> +	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
>>>> +	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
>>>> +	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
>>>> +	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
>>>> +	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
>>>> +
>>>> +	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);
>>>
>>> Can't you provide ub960_rxport_update_bits() ?
>>
>> I could, but I think it's worse:
>>
>> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
>> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
>> 		UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
>> 		UB960_RR_AEQ_BYPASS_ENABLE,
>> 	(eq_stage_1_select_value
>> 	 << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
>> 		(eq_stage_2_select_value
>> 		 << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
>> 		UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
>> );
>>
>> Indenting it differently, I think it's still worse:
>>
>> ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
>> 	UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
>> 	UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK |
>> 	UB960_RR_AEQ_BYPASS_ENABLE,
>> 	(eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT) |
>> 	(eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT) |
>> 	UB960_RR_AEQ_BYPASS_ENABLE /* Enable AEQ Bypass */
>> );
> 
> You can always use temporary variables to make code better to read.
> But it's up to you. Usually the R-M-W <--> vs. U is about locking or
> serialisation and handling it in a separate code is better.
> 
> ...
> 
>>>> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
>>>> +	if (ret)
>>>> +		return ret;
>>>
>>> Can this be read at once as BE16/LE16 value?
>>> Or if the stream of bytes, you can use le/be16_to_cpu().
>>
>> I'm not sure, possibly. But is it worth it? I'd need to add new helper
>> functions to read such a value.
> 
> I think it worth it to show exactly what is provided by the hardware
> and how we handle it (endianess wise).
> 
>>>> +	parity_errors = (v1 << 8) | v2;
> 
> ...
> 
>>>> +	*ok = !errors;
>>>
>>> How this is different to the something like returning 1 here (and 0 above)?
>>> You may save some code by dropping redundant parameter.
>>
>> Return value 1 means there was an error when reading the register values. 0
>> means we read the values, and "ok" contains a summary (ok or not) of the
>> link's status.
> 
> I was expecting that error is negative, no?

Ah, sorry. I meant the return value is negative if there was an error.

Yes, the "ok" value could be returned as 0 or 1. But I don't usually 
like combining the error code and the return value, it just makes 
messier code.

>>>> +	return 0;
> 
> ...
> 
>>>> +	while (time_before(jiffies, timeout)) {
>>>> +		missing = 0;
>>>> +
>>>> +		for_each_set_bit(nport, &port_mask,
>>>> +				 priv->hw_data->num_rxports) {
>>>> +			struct ub960_rxport *rxport = priv->rxports[nport];
>>>> +			bool ok;
>>>> +
>>>> +			if (!rxport)
>>>> +				continue;
>>>> +
>>>> +			ret = ub960_rxport_link_ok(priv, nport, &ok);
>>>> +			if (ret)
>>>> +				return ret;
>>>> +
>>>> +			if (!ok || !(link_ok_mask & BIT(nport)))
>>>> +				missing++;
>>>> +
>>>> +			if (ok)
>>>> +				link_ok_mask |= BIT(nport);
>>>> +			else
>>>> +				link_ok_mask &= ~BIT(nport);
>>>> +		}
>>>> +
>>>> +		loops++;
>>>> +
>>>> +		if (missing == 0)
>>>> +			break;
>>>> +
>>>> +		msleep(50);
>>>> +	}
>>>
>>> You can wrap the body into readx_poll_timeout() from iopoll.h.
>>
>> Hmm... How would I do that? With some kind of helper structs to wrap the
>> input and output parameters? Sounds very messy, but maybe I'm missing
>> something.
> 
> It's me who added extra 'x', what I meant is read_poll_timeout(). It
> accepts variadic arguments, i.o.w. any function with any arguments can
> be provided.

I see. Yes, I see how it would be used. read_poll_timeout() uses 
sleep_range, though, and we're sleeping more than the recommended limit 
of 20ms. It's also slightly messy, as we need to keep some state 
(link_ok_mask, loops is optional).

> ...
> 
>>>> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
>>>> +		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
>>>
>>> Same Q, can these be unified to some kind of bulk read?
>>
>> Perhaps, but again, I don't see the value for creating a bulk read helper
>> function for these few cases.
> 
> OK.
> 
> ...
> 
>>>> +		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
>>>> +			nport, strobe_pos, eq_level,
>>>> +			v1 * 1000000 + v2 * 1000000 / 256);
>>>
>>> Even this will be simpler with above suggestion.
>>
>> Hmm... How is that?
> 
> 		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
> 			nport, strobe_pos, eq_level, v * 1000000 / 256);
> 
> See?

Ah, of course, 256 is 1 << 8. The HW documentation just said that the 
high byte is the MHz part and the low byte is the fractional part in 
1/256, and I went with that without thinking about it.

This has the small complication that it overflows 32 bit variables, so I 
need to use 64 bit.

I have added 16 bit register access functions.

> ...
> 
>>>> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
>>>
>>> Post-inc?
>>
>> I still like pre-inc =).
>>
>> I see there's a mix os post and pre incs in the code. I'll align those when
>> I encounter them, but I don't think it's worth the effort to methodically go
>> through all of them to change them use the same style.
> 
> Kernel uses post-inc is an idiom for loops:
> 
> $ git grep -n -w '[_a-z0-9]\+++' | wc -l
> 148693
> 
> $ git grep -n -w ' ++[a-z0-9_]\+' | wc -l
> 8701
> 
> So, non-standard pattern needs to be explained.
> 
>>>> +	}
> 
> ...
> 
>>>> +	for (unsigned int i = 0; i < 6; ++i)
>>>> +		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
>>>> +	id[6] = 0;
>>>
>>> If it's only for printing, the 0 is not needed...
>>>
>>>> +	dev_info(dev, "ID '%s'\n", id);
>>>
>>> ...as you may put it as
>>>
>>> 	dev_info(dev, "ID: '%.*s'\n", (int)sizeof(id), id);
>>>
>>> (I wrote from the top of my head, maybe not compilable as is).
>>
>> And you think that is clearer? =)
> 
> To me, yes. Maybe because I'm familiar with that.
> 
>> I have to disagree.
> 
> Your right :-)
> 
> ...
> 
>> I'm not quite fine with dropping all these DT checks. If the user happens to
>> provide a DT with illegal values, the end results can be odd and the reason
>> quite difficult to figure out. Isn't it much better to have a few extra
>> checks in the driver?
> 
> As I said above, ask Rob, if he is fine with that I will have no objections.
> 
> ...
> 
>>>> +		rxport->eq.strobe_pos = strobe_pos;
>>>> +		if (!priv->strobe.manual)
>>>> +			dev_warn(dev,
>>>> +				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
>>>> +				 nport);
>>>> +	}
>>>
>>> This and below looks a bit different to the above in the same function. Perhaps
>>> these can be refactored to be less LoCs.
>>
>> Hmm what did you have in mind?
>>
>>>> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
>>>> +	if (ret) {
>>>> +		if (ret != -EINVAL) {
>>>> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
>>>> +				nport, ret);
>>>> +			return ret;
>>>> +		}
> 
> This seems like trying to handle special cases, if you want it to be optional,
> why not ignoring all errors?

I don't follow. Why would we ignore all errors even if the property is 
optional? If there's a failure in reading the property, or checking if 
it exists or not, surely that's an actual error to be handled, not to be 
ignored?

>>>> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
>>>> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
>>>> +			eq_level);
> 
> This part is a validation of DT again, but we discussed above this.
> 
>>>> +	} else {
>>>> +		rxport->eq.manual_eq = true;
>>>> +		rxport->eq.manual.eq_level = eq_level;
>>>> +	}
> 
> ...
> 
>>>> +err_pd_gpio:
>>>> +	if (priv->pd_gpio)
>>>
>>> Dup test.
>>
>> What do you mean dup? You mean gpiod_set_value_cansleep can be called with
>> gpio = NULL? The docs don't say this, but I guess that is the case.
> 
> Yes. This is the idea of having _optional() GPIO APIs.
> 
>>>> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> 
> ...
> 
>>>> +	if (priv->pd_gpio)
>>>> +		gpiod_set_value_cansleep(priv->pd_gpio, 1);
> 
> Ditto.
> 
> ...
> 
>>>> +	priv->hw_data = of_device_get_match_data(dev);
>>>
>>> Why of_ out of the blue?!
>>
>> Hmm... How do I get the data in a generic way? I'll have to study this a
>> bit.
> 
> Just drop of_ :-)
> 
> 	priv->hw_data = device_get_match_data(dev);
> 
>>>> +	if (!priv->hw_data)
>>>> +		return -ENODEV;
> 
> ...
> 
>>>> +	priv->current_indirect_target = 0xff;
>>>> +	priv->current_read_rxport = 0xff;
>>>> +	priv->current_write_rxport_mask = 0xff;
>>>> +	priv->current_read_csiport = 0xff;
>>>> +	priv->current_write_csiport_mask = 0xff;
>>>
>>> GENMASK()
>>
>> These are not masks, but invalid values. We set these to an invalid value
>> (0xff) so that when a reg access function next time checks if we are already
>> targeting, e.g. a particular rxport, it will always opt to select the rxport
>> by writing to the approriate registers.
> 
> Then define with respective name?

I think the comment just above these should be enough:

  * Initialize these to invalid values so that the first reg writes will
  * configure the target.

We're just initializing the fields to an unused value and the value has 
no other meaning, and is not used anywhere else. We could as well 
initialize to 0, and use +1 in the relevant code to avoid 0 being a 
valid value.

> ...
> 
>>>> +struct ds90ub9xx_platform_data {
>>>> +	u32 port;
>>>> +	struct i2c_atr *atr;
>>>> +	unsigned long bc_rate;
>>>
>>> Not sure why we need this to be public except, probably, atr...
>>
>> The port and atr are used by the serializers, for atr. The bc_rate is used
>> by the serializers to figure out the clocking (they may use the FPD-Link's
>> frequency internally).
> 
> The plain numbers can be passed as device properties. That's why the question
> about platform data. Platform data in general is discouraged to be used in a
> new code.

Device properties, as in, coming from DT? The port could be in the DT, 
but the others are not hardware properties.

Yes, I don't like using platform data. We need some way to pass 
information between the drivers. Maybe a custom FPD-Link bus could do 
that, but that's then going into totally new directions.

  Tomi
Andy Shevchenko Jan. 25, 2023, 12:10 p.m. UTC | #6
On Wed, Jan 25, 2023 at 01:15:34PM +0200, Tomi Valkeinen wrote:
> On 20/01/2023 18:47, Andy Shevchenko wrote:

...

> > > > Esp. taking into account that some of them are using actually
> > > > post-inc. Why this difference?
> > > 
> > > Possibly a different person has written that particular piece of code, or
> > > maybe a copy paste from somewhere.
> > > 
> > > I'm personally fine with seeing both post and pre increments in code.
> > 
> > I'm not :-), if it's not required by the code. Pre-increment always puzzles
> > me: Is here anything I have to pay an additional attention to?
> 
> That is interesting, as to me pre-increment is the simpler, more obvious
> case. It's just:
> 
> v = v + 1
> v
> 
> Whereas post-increment is:
> 
> temp = v
> v = v + 1
> temp
> 
> In any case, we're side-tracking here, I think =).

Yes, just see the statistics of use below.

...

> > > > > +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
> > > > 
> > > > Post-inc?
> > > 
> > > I still like pre-inc =).
> > > 
> > > I see there's a mix os post and pre incs in the code. I'll align those when
> > > I encounter them, but I don't think it's worth the effort to methodically go
> > > through all of them to change them use the same style.
> > 
> > Kernel uses post-inc is an idiom for loops:
> > 
> > $ git grep -n -w '[_a-z0-9]\+++' | wc -l
> > 148693
> > 
> > $ git grep -n -w ' ++[a-z0-9_]\+' | wc -l
> > 8701
> > 
> > So, non-standard pattern needs to be explained.

> > > > > +	}

...

> > > > > +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> > > > > +	if (ret) {
> > > > > +		if (ret != -EINVAL) {
> > > > > +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> > > > > +				nport, ret);
> > > > > +			return ret;
> > > > > +		}
> > 
> > This seems like trying to handle special cases, if you want it to be optional,
> > why not ignoring all errors?
> 
> I don't follow. Why would we ignore all errors even if the property is
> optional? If there's a failure in reading the property, or checking if it
> exists or not, surely that's an actual error to be handled, not to be
> ignored?

What the problem to ignore them?

But if you are really pedantic about it, perhaps the proper way is to add

fwnode_property_*_optional()

APIs to the set where you take default and return 0 in case default had been
used for the absent property.

> > > > > +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> > > > > +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> > > > > +			eq_level);
> > 
> > This part is a validation of DT again, but we discussed above this.
> > 
> > > > > +	} else {
> > > > > +		rxport->eq.manual_eq = true;
> > > > > +		rxport->eq.manual.eq_level = eq_level;
> > > > > +	}

...

> > > > > +struct ds90ub9xx_platform_data {
> > > > > +	u32 port;
> > > > > +	struct i2c_atr *atr;
> > > > > +	unsigned long bc_rate;
> > > > 
> > > > Not sure why we need this to be public except, probably, atr...
> > > 
> > > The port and atr are used by the serializers, for atr. The bc_rate is used
> > > by the serializers to figure out the clocking (they may use the FPD-Link's
> > > frequency internally).
> > 
> > The plain numbers can be passed as device properties. That's why the question
> > about platform data. Platform data in general is discouraged to be used in a
> > new code.
> 
> Device properties, as in, coming from DT?

From anywhere.

> The port could be in the DT, but
> the others are not hardware properties.

Why do we need them? For example, bc_rate.

> Yes, I don't like using platform data. We need some way to pass information
> between the drivers.

Device properties allow that and targeting to remove the legacy platform data
in zillions of the drivers.

> Maybe a custom FPD-Link bus could do that, but that's
> then going into totally new directions.
Tomi Valkeinen Jan. 25, 2023, 1:33 p.m. UTC | #7
On 25/01/2023 14:10, Andy Shevchenko wrote:
> On Wed, Jan 25, 2023 at 01:15:34PM +0200, Tomi Valkeinen wrote:
>> On 20/01/2023 18:47, Andy Shevchenko wrote:
> 
> ...
> 
>>>>> Esp. taking into account that some of them are using actually
>>>>> post-inc. Why this difference?
>>>>
>>>> Possibly a different person has written that particular piece of code, or
>>>> maybe a copy paste from somewhere.
>>>>
>>>> I'm personally fine with seeing both post and pre increments in code.
>>>
>>> I'm not :-), if it's not required by the code. Pre-increment always puzzles
>>> me: Is here anything I have to pay an additional attention to?
>>
>> That is interesting, as to me pre-increment is the simpler, more obvious
>> case. It's just:
>>
>> v = v + 1
>> v
>>
>> Whereas post-increment is:
>>
>> temp = v
>> v = v + 1
>> temp
>>
>> In any case, we're side-tracking here, I think =).
> 
> Yes, just see the statistics of use below.
> 
> ...
> 
>>>>>> +	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
>>>>>
>>>>> Post-inc?
>>>>
>>>> I still like pre-inc =).
>>>>
>>>> I see there's a mix os post and pre incs in the code. I'll align those when
>>>> I encounter them, but I don't think it's worth the effort to methodically go
>>>> through all of them to change them use the same style.
>>>
>>> Kernel uses post-inc is an idiom for loops:
>>>
>>> $ git grep -n -w '[_a-z0-9]\+++' | wc -l
>>> 148693
>>>
>>> $ git grep -n -w ' ++[a-z0-9_]\+' | wc -l
>>> 8701
>>>
>>> So, non-standard pattern needs to be explained.
> 
>>>>>> +	}
> 
> ...
> 
>>>>>> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
>>>>>> +	if (ret) {
>>>>>> +		if (ret != -EINVAL) {
>>>>>> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
>>>>>> +				nport, ret);
>>>>>> +			return ret;
>>>>>> +		}
>>>
>>> This seems like trying to handle special cases, if you want it to be optional,
>>> why not ignoring all errors?
>>
>> I don't follow. Why would we ignore all errors even if the property is
>> optional? If there's a failure in reading the property, or checking if it
>> exists or not, surely that's an actual error to be handled, not to be
>> ignored?
> 
> What the problem to ignore them?

Well, probably nothing will explode if we just ignore them. But... Why 
would we ignore them?

> But if you are really pedantic about it, perhaps the proper way is to add
> 
> fwnode_property_*_optional()
> 
> APIs to the set where you take default and return 0 in case default had been
> used for the absent property.

Perhaps, but I don't have a default value here.

In any case, I'm not quite sure what you are arguing here. Is it just 
that you don't think the error check is necessary and should be dropped?

>>>>>> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
>>>>>> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
>>>>>> +			eq_level);
>>>
>>> This part is a validation of DT again, but we discussed above this.
>>>
>>>>>> +	} else {
>>>>>> +		rxport->eq.manual_eq = true;
>>>>>> +		rxport->eq.manual.eq_level = eq_level;
>>>>>> +	}
> 
> ...
> 
>>>>>> +struct ds90ub9xx_platform_data {
>>>>>> +	u32 port;
>>>>>> +	struct i2c_atr *atr;
>>>>>> +	unsigned long bc_rate;
>>>>>
>>>>> Not sure why we need this to be public except, probably, atr...
>>>>
>>>> The port and atr are used by the serializers, for atr. The bc_rate is used
>>>> by the serializers to figure out the clocking (they may use the FPD-Link's
>>>> frequency internally).
>>>
>>> The plain numbers can be passed as device properties. That's why the question
>>> about platform data. Platform data in general is discouraged to be used in a
>>> new code.
>>
>> Device properties, as in, coming from DT?
> 
>  From anywhere.
> 
>> The port could be in the DT, but
>> the others are not hardware properties.
> 
> Why do we need them? For example, bc_rate.

The atr pointer is needed so that the serializers (ub913, ub953) can add 
their i2c adapter to the deserializer's i2c-atr. The port is also needed 
for that.

The bc rate (back-channel rate) is the FPD-Link back-channel rate which 
the serializers use for various functionalities. At the moment only the 
ub953 uses it for calculating an output clock rate.

The bc-rate could be implemented using the clock framework, even if it's 
not quite a plain clock. I had that code at some point, but it felt a 
bit off and as we needed the pdata for the ATR, I added the bc-rate there.

>> Yes, I don't like using platform data. We need some way to pass information
>> between the drivers.
> 
> Device properties allow that and targeting to remove the legacy platform data
> in zillions of the drivers.

Do you have any pointers to guide me into the right direction? I 
couldn't find anything with some grepping and googling.

If you mean "device properties" as in ACPI, and so similar to DT 
properties, aren't those hardware properties? Only the port here is 
about the hardware.

  Tomi
Andy Shevchenko Jan. 25, 2023, 2:49 p.m. UTC | #8
On Wed, Jan 25, 2023 at 03:33:35PM +0200, Tomi Valkeinen wrote:
> On 25/01/2023 14:10, Andy Shevchenko wrote:
> > On Wed, Jan 25, 2023 at 01:15:34PM +0200, Tomi Valkeinen wrote:
> > > On 20/01/2023 18:47, Andy Shevchenko wrote:

...

> > > > > > > +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> > > > > > > +	if (ret) {
> > > > > > > +		if (ret != -EINVAL) {
> > > > > > > +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> > > > > > > +				nport, ret);
> > > > > > > +			return ret;
> > > > > > > +		}
> > > > 
> > > > This seems like trying to handle special cases, if you want it to be optional,
> > > > why not ignoring all errors?
> > > 
> > > I don't follow. Why would we ignore all errors even if the property is
> > > optional? If there's a failure in reading the property, or checking if it
> > > exists or not, surely that's an actual error to be handled, not to be
> > > ignored?
> > 
> > What the problem to ignore them?
> 
> Well, probably nothing will explode if we just ignore them. But... Why would
> we ignore them?
> 
> > But if you are really pedantic about it, perhaps the proper way is to add
> > 
> > fwnode_property_*_optional()
> > 
> > APIs to the set where you take default and return 0 in case default had been
> > used for the absent property.
> 
> Perhaps, but I don't have a default value here.

It's impossible. You have one. 0 is also can be default.

> In any case, I'm not quite sure what you are arguing here. Is it just that
> you don't think the error check is necessary and should be dropped?

Yes, I do not see the value of these complex error checking.
Dropping that makes it KISS. I.o.w. why do we care about errors
if the property is optional? Make it mandatory otherwise.

> > > > > > > +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> > > > > > > +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> > > > > > > +			eq_level);
> > > > 
> > > > This part is a validation of DT again, but we discussed above this.
> > > > 
> > > > > > > +	} else {
> > > > > > > +		rxport->eq.manual_eq = true;
> > > > > > > +		rxport->eq.manual.eq_level = eq_level;
> > > > > > > +	}
> > 
> > ...
> > 
> > > > > > > +struct ds90ub9xx_platform_data {
> > > > > > > +	u32 port;
> > > > > > > +	struct i2c_atr *atr;
> > > > > > > +	unsigned long bc_rate;
> > > > > > 
> > > > > > Not sure why we need this to be public except, probably, atr...
> > > > > 
> > > > > The port and atr are used by the serializers, for atr. The bc_rate is used
> > > > > by the serializers to figure out the clocking (they may use the FPD-Link's
> > > > > frequency internally).
> > > > 
> > > > The plain numbers can be passed as device properties. That's why the question
> > > > about platform data. Platform data in general is discouraged to be used in a
> > > > new code.
> > > 
> > > Device properties, as in, coming from DT?
> > 
> >  From anywhere.
> > 
> > > The port could be in the DT, but
> > > the others are not hardware properties.
> > 
> > Why do we need them? For example, bc_rate.
> 
> The atr pointer is needed so that the serializers (ub913, ub953) can add
> their i2c adapter to the deserializer's i2c-atr. The port is also needed for
> that.
> 
> The bc rate (back-channel rate) is the FPD-Link back-channel rate which the
> serializers use for various functionalities. At the moment only the ub953
> uses it for calculating an output clock rate.
> 
> The bc-rate could be implemented using the clock framework, even if it's not
> quite a plain clock. I had that code at some point, but it felt a bit off
> and as we needed the pdata for the ATR, I added the bc-rate there.

And I don't see why it is not a property of the device.

> > > Yes, I don't like using platform data. We need some way to pass information
> > > between the drivers.
> > 
> > Device properties allow that and targeting to remove the legacy platform data
> > in zillions of the drivers.
> 
> Do you have any pointers to guide me into the right direction? I couldn't
> find anything with some grepping and googling.
> 
> If you mean "device properties" as in ACPI, and so similar to DT properties,
> aren't those hardware properties? Only the port here is about the hardware.

About hardware, or PCB, or as quirks for missing DT/ACPI/any FW properties,
like clock rates.

The Linux kernel layer for that is called software nodes. The rough
approximation to see where and how it's being used can be achieved
by grepping for specific macros:

	git grep -lw PROPERTY_ENTRY_.*

E.g. arch/arm/mach-tegra/board-paz00.c tegra_paz00_wifikill_init()
implementation.
Tomi Valkeinen Jan. 25, 2023, 3:14 p.m. UTC | #9
On 25/01/2023 16:49, Andy Shevchenko wrote:
> On Wed, Jan 25, 2023 at 03:33:35PM +0200, Tomi Valkeinen wrote:
>> On 25/01/2023 14:10, Andy Shevchenko wrote:
>>> On Wed, Jan 25, 2023 at 01:15:34PM +0200, Tomi Valkeinen wrote:
>>>> On 20/01/2023 18:47, Andy Shevchenko wrote:
> 
> ...
> 
>>>>>>>> +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
>>>>>>>> +	if (ret) {
>>>>>>>> +		if (ret != -EINVAL) {
>>>>>>>> +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
>>>>>>>> +				nport, ret);
>>>>>>>> +			return ret;
>>>>>>>> +		}
>>>>>
>>>>> This seems like trying to handle special cases, if you want it to be optional,
>>>>> why not ignoring all errors?
>>>>
>>>> I don't follow. Why would we ignore all errors even if the property is
>>>> optional? If there's a failure in reading the property, or checking if it
>>>> exists or not, surely that's an actual error to be handled, not to be
>>>> ignored?
>>>
>>> What the problem to ignore them?
>>
>> Well, probably nothing will explode if we just ignore them. But... Why would
>> we ignore them?
>>
>>> But if you are really pedantic about it, perhaps the proper way is to add
>>>
>>> fwnode_property_*_optional()
>>>
>>> APIs to the set where you take default and return 0 in case default had been
>>> used for the absent property.
>>
>> Perhaps, but I don't have a default value here.
> 
> It's impossible. You have one. 0 is also can be default.

No, I either have the value ("eq-level"), or it's undefined, not used, 
doesn't exist. There's no default eq-level.

>> In any case, I'm not quite sure what you are arguing here. Is it just that
>> you don't think the error check is necessary and should be dropped?
> 
> Yes, I do not see the value of these complex error checking.
> Dropping that makes it KISS. I.o.w. why do we care about errors
> if the property is optional? Make it mandatory otherwise.

If the call fails, there's an error somewhere. Maybe the user tried to 
define eq-level, but something is wrong. Isn't it better to catch that 
error, rather than ignoring it, leaving the user wonder why things don't 
work as he expects?

>>>>>>>> +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
>>>>>>>> +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
>>>>>>>> +			eq_level);
>>>>>
>>>>> This part is a validation of DT again, but we discussed above this.
>>>>>
>>>>>>>> +	} else {
>>>>>>>> +		rxport->eq.manual_eq = true;
>>>>>>>> +		rxport->eq.manual.eq_level = eq_level;
>>>>>>>> +	}
>>>
>>> ...
>>>
>>>>>>>> +struct ds90ub9xx_platform_data {
>>>>>>>> +	u32 port;
>>>>>>>> +	struct i2c_atr *atr;
>>>>>>>> +	unsigned long bc_rate;
>>>>>>>
>>>>>>> Not sure why we need this to be public except, probably, atr...
>>>>>>
>>>>>> The port and atr are used by the serializers, for atr. The bc_rate is used
>>>>>> by the serializers to figure out the clocking (they may use the FPD-Link's
>>>>>> frequency internally).
>>>>>
>>>>> The plain numbers can be passed as device properties. That's why the question
>>>>> about platform data. Platform data in general is discouraged to be used in a
>>>>> new code.
>>>>
>>>> Device properties, as in, coming from DT?
>>>
>>>   From anywhere.
>>>
>>>> The port could be in the DT, but
>>>> the others are not hardware properties.
>>>
>>> Why do we need them? For example, bc_rate.
>>
>> The atr pointer is needed so that the serializers (ub913, ub953) can add
>> their i2c adapter to the deserializer's i2c-atr. The port is also needed for
>> that.
>>
>> The bc rate (back-channel rate) is the FPD-Link back-channel rate which the
>> serializers use for various functionalities. At the moment only the ub953
>> uses it for calculating an output clock rate.
>>
>> The bc-rate could be implemented using the clock framework, even if it's not
>> quite a plain clock. I had that code at some point, but it felt a bit off
>> and as we needed the pdata for the ATR, I added the bc-rate there.
> 
> And I don't see why it is not a property of the device.

It with a "property of the device" you mean a hardware property, it's 
not because we don't know it, it can be changed at runtime. It's not 
supposed to change after probing the serializer, but up to that point it 
can change.

>>>> Yes, I don't like using platform data. We need some way to pass information
>>>> between the drivers.
>>>
>>> Device properties allow that and targeting to remove the legacy platform data
>>> in zillions of the drivers.
>>
>> Do you have any pointers to guide me into the right direction? I couldn't
>> find anything with some grepping and googling.
>>
>> If you mean "device properties" as in ACPI, and so similar to DT properties,
>> aren't those hardware properties? Only the port here is about the hardware.
> 
> About hardware, or PCB, or as quirks for missing DT/ACPI/any FW properties,
> like clock rates.
> 
> The Linux kernel layer for that is called software nodes. The rough
> approximation to see where and how it's being used can be achieved
> by grepping for specific macros:
> 
> 	git grep -lw PROPERTY_ENTRY_.*
> 
> E.g. arch/arm/mach-tegra/board-paz00.c tegra_paz00_wifikill_init()
> implementation.

Thanks, I'll have a look. But I presume we can only pass "plain" values, 
so it won't work for the ATR pointer anyway.

  Tomi
Andy Shevchenko Jan. 25, 2023, 3:27 p.m. UTC | #10
On Wed, Jan 25, 2023 at 05:14:59PM +0200, Tomi Valkeinen wrote:
> On 25/01/2023 16:49, Andy Shevchenko wrote:
> > On Wed, Jan 25, 2023 at 03:33:35PM +0200, Tomi Valkeinen wrote:
> > > On 25/01/2023 14:10, Andy Shevchenko wrote:
> > > > On Wed, Jan 25, 2023 at 01:15:34PM +0200, Tomi Valkeinen wrote:
> > > > > On 20/01/2023 18:47, Andy Shevchenko wrote:

...

> > > > > > > > > +	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
> > > > > > > > > +	if (ret) {
> > > > > > > > > +		if (ret != -EINVAL) {
> > > > > > > > > +			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
> > > > > > > > > +				nport, ret);
> > > > > > > > > +			return ret;
> > > > > > > > > +		}
> > > > > > 
> > > > > > This seems like trying to handle special cases, if you want it to be optional,
> > > > > > why not ignoring all errors?
> > > > > 
> > > > > I don't follow. Why would we ignore all errors even if the property is
> > > > > optional? If there's a failure in reading the property, or checking if it
> > > > > exists or not, surely that's an actual error to be handled, not to be
> > > > > ignored?
> > > > 
> > > > What the problem to ignore them?
> > > 
> > > Well, probably nothing will explode if we just ignore them. But... Why would
> > > we ignore them?
> > > 
> > > > But if you are really pedantic about it, perhaps the proper way is to add
> > > > 
> > > > fwnode_property_*_optional()
> > > > 
> > > > APIs to the set where you take default and return 0 in case default had been
> > > > used for the absent property.
> > > 
> > > Perhaps, but I don't have a default value here.
> > 
> > It's impossible. You have one. 0 is also can be default.
> 
> No, I either have the value ("eq-level"), or it's undefined, not used,
> doesn't exist. There's no default eq-level.
> 
> > > In any case, I'm not quite sure what you are arguing here. Is it just that
> > > you don't think the error check is necessary and should be dropped?
> > 
> > Yes, I do not see the value of these complex error checking.
> > Dropping that makes it KISS. I.o.w. why do we care about errors
> > if the property is optional? Make it mandatory otherwise.
> 
> If the call fails, there's an error somewhere. Maybe the user tried to
> define eq-level, but something is wrong. Isn't it better to catch that
> error, rather than ignoring it, leaving the user wonder why things don't
> work as he expects?

I expressed my opinion, if you and maintainers think otherwise, fine.
I don't won't spend more time on this :-)

> > > > > > > > > +	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
> > > > > > > > > +		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
> > > > > > > > > +			eq_level);
> > > > > > 
> > > > > > This part is a validation of DT again, but we discussed above this.
> > > > > > 
> > > > > > > > > +	} else {
> > > > > > > > > +		rxport->eq.manual_eq = true;
> > > > > > > > > +		rxport->eq.manual.eq_level = eq_level;
> > > > > > > > > +	}

...

> > > > > > > > > +struct ds90ub9xx_platform_data {
> > > > > > > > > +	u32 port;
> > > > > > > > > +	struct i2c_atr *atr;
> > > > > > > > > +	unsigned long bc_rate;
> > > > > > > > 
> > > > > > > > Not sure why we need this to be public except, probably, atr...
> > > > > > > 
> > > > > > > The port and atr are used by the serializers, for atr. The bc_rate is used
> > > > > > > by the serializers to figure out the clocking (they may use the FPD-Link's
> > > > > > > frequency internally).
> > > > > > 
> > > > > > The plain numbers can be passed as device properties. That's why the question
> > > > > > about platform data. Platform data in general is discouraged to be used in a
> > > > > > new code.
> > > > > 
> > > > > Device properties, as in, coming from DT?
> > > > 
> > > >   From anywhere.
> > > > 
> > > > > The port could be in the DT, but
> > > > > the others are not hardware properties.
> > > > 
> > > > Why do we need them? For example, bc_rate.
> > > 
> > > The atr pointer is needed so that the serializers (ub913, ub953) can add
> > > their i2c adapter to the deserializer's i2c-atr. The port is also needed for
> > > that.
> > > 
> > > The bc rate (back-channel rate) is the FPD-Link back-channel rate which the
> > > serializers use for various functionalities. At the moment only the ub953
> > > uses it for calculating an output clock rate.
> > > 
> > > The bc-rate could be implemented using the clock framework, even if it's not
> > > quite a plain clock. I had that code at some point, but it felt a bit off
> > > and as we needed the pdata for the ATR, I added the bc-rate there.
> > 
> > And I don't see why it is not a property of the device.
> 
> It with a "property of the device" you mean a hardware property, it's not
> because we don't know it, it can be changed at runtime. It's not supposed to
> change after probing the serializer, but up to that point it can change.

Yes, which is still property of the device, isn't it?

> > > > > Yes, I don't like using platform data. We need some way to pass information
> > > > > between the drivers.
> > > > 
> > > > Device properties allow that and targeting to remove the legacy platform data
> > > > in zillions of the drivers.
> > > 
> > > Do you have any pointers to guide me into the right direction? I couldn't
> > > find anything with some grepping and googling.
> > > 
> > > If you mean "device properties" as in ACPI, and so similar to DT properties,
> > > aren't those hardware properties? Only the port here is about the hardware.
> > 
> > About hardware, or PCB, or as quirks for missing DT/ACPI/any FW properties,
> > like clock rates.
> > 
> > The Linux kernel layer for that is called software nodes. The rough
> > approximation to see where and how it's being used can be achieved
> > by grepping for specific macros:
> > 
> > 	git grep -lw PROPERTY_ENTRY_.*
> > 
> > E.g. arch/arm/mach-tegra/board-paz00.c tegra_paz00_wifikill_init()
> > implementation.
> 
> Thanks, I'll have a look. But I presume we can only pass "plain" values, so
> it won't work for the ATR pointer anyway.

Yes, that's what I have told at the very beginning when answering to your
patch.

But I probably don't understand the ATR structure and what exactly we need to
pass to it, perhaps it also can be replaced with properties (note, that we have
some interesting ones that called references, which is an alternative to DT
phandle).
Tomi Valkeinen Jan. 26, 2023, 8:41 a.m. UTC | #11
On 25/01/2023 17:27, Andy Shevchenko wrote:

>>>>>>>>>> +struct ds90ub9xx_platform_data {
>>>>>>>>>> +	u32 port;
>>>>>>>>>> +	struct i2c_atr *atr;
>>>>>>>>>> +	unsigned long bc_rate;
>>>>>>>>>
>>>>>>>>> Not sure why we need this to be public except, probably, atr...
>>>>>>>>
>>>>>>>> The port and atr are used by the serializers, for atr. The bc_rate is used
>>>>>>>> by the serializers to figure out the clocking (they may use the FPD-Link's
>>>>>>>> frequency internally).
>>>>>>>
>>>>>>> The plain numbers can be passed as device properties. That's why the question
>>>>>>> about platform data. Platform data in general is discouraged to be used in a
>>>>>>> new code.
>>>>>>
>>>>>> Device properties, as in, coming from DT?
>>>>>
>>>>>    From anywhere.
>>>>>
>>>>>> The port could be in the DT, but
>>>>>> the others are not hardware properties.
>>>>>
>>>>> Why do we need them? For example, bc_rate.
>>>>
>>>> The atr pointer is needed so that the serializers (ub913, ub953) can add
>>>> their i2c adapter to the deserializer's i2c-atr. The port is also needed for
>>>> that.
>>>>
>>>> The bc rate (back-channel rate) is the FPD-Link back-channel rate which the
>>>> serializers use for various functionalities. At the moment only the ub953
>>>> uses it for calculating an output clock rate.
>>>>
>>>> The bc-rate could be implemented using the clock framework, even if it's not
>>>> quite a plain clock. I had that code at some point, but it felt a bit off
>>>> and as we needed the pdata for the ATR, I added the bc-rate there.
>>>
>>> And I don't see why it is not a property of the device.
>>
>> It with a "property of the device" you mean a hardware property, it's not
>> because we don't know it, it can be changed at runtime. It's not supposed to
>> change after probing the serializer, but up to that point it can change.
> 
> Yes, which is still property of the device, isn't it?

No, I don't see it as a property of the serializer device.

The deserializer sends messages to the serializer over the back-channel. 
The rate of the back-channel is defined by the clock used for 
deserializer's refclock, and internal deserializer configuration. The 
serializer may use the back-channel rate for its own operations.

>>>>>> Yes, I don't like using platform data. We need some way to pass information
>>>>>> between the drivers.
>>>>>
>>>>> Device properties allow that and targeting to remove the legacy platform data
>>>>> in zillions of the drivers.
>>>>
>>>> Do you have any pointers to guide me into the right direction? I couldn't
>>>> find anything with some grepping and googling.
>>>>
>>>> If you mean "device properties" as in ACPI, and so similar to DT properties,
>>>> aren't those hardware properties? Only the port here is about the hardware.
>>>
>>> About hardware, or PCB, or as quirks for missing DT/ACPI/any FW properties,
>>> like clock rates.
>>>
>>> The Linux kernel layer for that is called software nodes. The rough
>>> approximation to see where and how it's being used can be achieved
>>> by grepping for specific macros:
>>>
>>> 	git grep -lw PROPERTY_ENTRY_.*
>>>
>>> E.g. arch/arm/mach-tegra/board-paz00.c tegra_paz00_wifikill_init()
>>> implementation.
>>
>> Thanks, I'll have a look. But I presume we can only pass "plain" values, so
>> it won't work for the ATR pointer anyway.
> 
> Yes, that's what I have told at the very beginning when answering to your
> patch.
> 
> But I probably don't understand the ATR structure and what exactly we need to
> pass to it, perhaps it also can be replaced with properties (note, that we have
> some interesting ones that called references, which is an alternative to DT
> phandle).

Well, maybe this needs a Linux bus implementation. I'm not that familiar 
with implementing a bus, but I think that would make it easier to share 
data between the deserializer and the serializer. A bus sounds a bit 
like an overkill for a 1-to-1 connection, used by a few drivers, but 
maybe it wouldn't be too much code.

  Tomi
Andy Shevchenko Jan. 26, 2023, 10:21 a.m. UTC | #12
On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
> On 25/01/2023 17:27, Andy Shevchenko wrote:

...

> > But I probably don't understand the ATR structure and what exactly we need to
> > pass to it, perhaps it also can be replaced with properties (note, that we have
> > some interesting ones that called references, which is an alternative to DT
> > phandle).
> 
> Well, maybe this needs a Linux bus implementation. I'm not that familiar
> with implementing a bus, but I think that would make it easier to share data
> between the deserializer and the serializer. A bus sounds a bit like an
> overkill for a 1-to-1 connection, used by a few drivers, but maybe it
> wouldn't be too much code.

Have you looked at auxiliary bus (appeared a few releases ago in kernel)?
Laurent Pinchart Jan. 26, 2023, 10:51 a.m. UTC | #13
On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote:
> On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
> > On 25/01/2023 17:27, Andy Shevchenko wrote:
> 
> ...
> 
> > > But I probably don't understand the ATR structure and what exactly we need to
> > > pass to it, perhaps it also can be replaced with properties (note, that we have
> > > some interesting ones that called references, which is an alternative to DT
> > > phandle).
> > 
> > Well, maybe this needs a Linux bus implementation. I'm not that familiar
> > with implementing a bus, but I think that would make it easier to share data
> > between the deserializer and the serializer. A bus sounds a bit like an
> > overkill for a 1-to-1 connection, used by a few drivers, but maybe it
> > wouldn't be too much code.
> 
> Have you looked at auxiliary bus (appeared a few releases ago in kernel)?

As far as I understand, the auxiliary bus infrastructure is meant for
use cases where a single hardware device needs to be split into multiple
logical devices (as in struct device). Platform devices were
historically (ab)used for this, and the auxiliary bus is meant as a
cleaner solution. I'm not sure if it would be a good match here, or if
it would be considered an abuse of the auxiliary bus API.
Tomi Valkeinen Jan. 27, 2023, 8:24 a.m. UTC | #14
On 26/01/2023 12:51, Laurent Pinchart wrote:
> On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote:
>> On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
>>> On 25/01/2023 17:27, Andy Shevchenko wrote:
>>
>> ...
>>
>>>> But I probably don't understand the ATR structure and what exactly we need to
>>>> pass to it, perhaps it also can be replaced with properties (note, that we have
>>>> some interesting ones that called references, which is an alternative to DT
>>>> phandle).
>>>
>>> Well, maybe this needs a Linux bus implementation. I'm not that familiar
>>> with implementing a bus, but I think that would make it easier to share data
>>> between the deserializer and the serializer. A bus sounds a bit like an
>>> overkill for a 1-to-1 connection, used by a few drivers, but maybe it
>>> wouldn't be too much code.
>>
>> Have you looked at auxiliary bus (appeared a few releases ago in kernel)?
> 
> As far as I understand, the auxiliary bus infrastructure is meant for
> use cases where a single hardware device needs to be split into multiple
> logical devices (as in struct device). Platform devices were
> historically (ab)used for this, and the auxiliary bus is meant as a
> cleaner solution. I'm not sure if it would be a good match here, or if
> it would be considered an abuse of the auxiliary bus API.

The aux bus docs say "A key requirement for utilizing the auxiliary bus 
is that there is no dependency on a physical bus, device, register 
accesses or regmap support. These individual devices split from the core 
cannot live on the platform bus as they are not physical devices that 
are controlled by DT/ACPI.", which doesn't sound like a good fit.

The deserializer and serializers are currently independent devices and 
drivers (the pdata is the only shared thing), but I think we may need 
something better here. The devices are more tightly tied together than 
"normal" video devices, in my opinion, as the serializer is fully 
controlled by the deserializer (including power).

And if we ever want to implement something like power management, we 
probably need something more than what we have now. Although I don't 
know how that would be done, as all the peripherals behind the 
serializer would also lose power...

  Tomi
Andy Shevchenko Jan. 27, 2023, 9:15 a.m. UTC | #15
On Fri, Jan 27, 2023 at 10:24:04AM +0200, Tomi Valkeinen wrote:
> On 26/01/2023 12:51, Laurent Pinchart wrote:
> > On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote:
> > > On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
> > > > On 25/01/2023 17:27, Andy Shevchenko wrote:

...

> > > > > But I probably don't understand the ATR structure and what exactly we need to
> > > > > pass to it, perhaps it also can be replaced with properties (note, that we have
> > > > > some interesting ones that called references, which is an alternative to DT
> > > > > phandle).
> > > > 
> > > > Well, maybe this needs a Linux bus implementation. I'm not that familiar
> > > > with implementing a bus, but I think that would make it easier to share data
> > > > between the deserializer and the serializer. A bus sounds a bit like an
> > > > overkill for a 1-to-1 connection, used by a few drivers, but maybe it
> > > > wouldn't be too much code.
> > > 
> > > Have you looked at auxiliary bus (appeared a few releases ago in kernel)?
> > 
> > As far as I understand, the auxiliary bus infrastructure is meant for
> > use cases where a single hardware device needs to be split into multiple
> > logical devices (as in struct device). Platform devices were
> > historically (ab)used for this, and the auxiliary bus is meant as a
> > cleaner solution. I'm not sure if it would be a good match here, or if
> > it would be considered an abuse of the auxiliary bus API.
> 
> The aux bus docs say "A key requirement for utilizing the auxiliary bus is
> that there is no dependency on a physical bus, device, register accesses or
> regmap support. These individual devices split from the core cannot live on
> the platform bus as they are not physical devices that are controlled by
> DT/ACPI.", which doesn't sound like a good fit.

Thanks for checking!

> The deserializer and serializers are currently independent devices and
> drivers (the pdata is the only shared thing), but I think we may need
> something better here. The devices are more tightly tied together than
> "normal" video devices, in my opinion, as the serializer is fully controlled
> by the deserializer (including power).
> 
> And if we ever want to implement something like power management, we
> probably need something more than what we have now. Although I don't know
> how that would be done, as all the peripherals behind the serializer would
> also lose power...

I believe you have to create a power domain for them and when such device
is added, the power domain of it should belong to the serialized.
Tomi Valkeinen Feb. 8, 2023, 3:10 p.m. UTC | #16
On 27/01/2023 11:15, Andy Shevchenko wrote:
> On Fri, Jan 27, 2023 at 10:24:04AM +0200, Tomi Valkeinen wrote:
>> On 26/01/2023 12:51, Laurent Pinchart wrote:
>>> On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote:
>>>> On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
>>>>> On 25/01/2023 17:27, Andy Shevchenko wrote:
> 
> ...
> 
>>>>>> But I probably don't understand the ATR structure and what exactly we need to
>>>>>> pass to it, perhaps it also can be replaced with properties (note, that we have
>>>>>> some interesting ones that called references, which is an alternative to DT
>>>>>> phandle).
>>>>>
>>>>> Well, maybe this needs a Linux bus implementation. I'm not that familiar
>>>>> with implementing a bus, but I think that would make it easier to share data
>>>>> between the deserializer and the serializer. A bus sounds a bit like an
>>>>> overkill for a 1-to-1 connection, used by a few drivers, but maybe it
>>>>> wouldn't be too much code.
>>>>
>>>> Have you looked at auxiliary bus (appeared a few releases ago in kernel)?
>>>
>>> As far as I understand, the auxiliary bus infrastructure is meant for
>>> use cases where a single hardware device needs to be split into multiple
>>> logical devices (as in struct device). Platform devices were
>>> historically (ab)used for this, and the auxiliary bus is meant as a
>>> cleaner solution. I'm not sure if it would be a good match here, or if
>>> it would be considered an abuse of the auxiliary bus API.
>>
>> The aux bus docs say "A key requirement for utilizing the auxiliary bus is
>> that there is no dependency on a physical bus, device, register accesses or
>> regmap support. These individual devices split from the core cannot live on
>> the platform bus as they are not physical devices that are controlled by
>> DT/ACPI.", which doesn't sound like a good fit.
> 
> Thanks for checking!
> 
>> The deserializer and serializers are currently independent devices and
>> drivers (the pdata is the only shared thing), but I think we may need
>> something better here. The devices are more tightly tied together than
>> "normal" video devices, in my opinion, as the serializer is fully controlled
>> by the deserializer (including power).
>>
>> And if we ever want to implement something like power management, we
>> probably need something more than what we have now. Although I don't know
>> how that would be done, as all the peripherals behind the serializer would
>> also lose power...
> 
> I believe you have to create a power domain for them and when such device
> is added, the power domain of it should belong to the serialized.

I was testing this, and got something working.

I have the deserializer introducing a separate power-domain for each RX 
port, and the serializer and the sensor both refer to their port's 
domain. I can see that the deserializer gets power on/off callbacks 
correctly when either serializer or sensor resumes.

The problem I have now is that while the power comes from the 
deserializer and is thus covered with the power domain, the sensor uses 
services from the serializer (gpios, clocks, i2c bus), and the 
serializer is not woken up when the sensor does runtime-pm resume (the 
power domain is powered up correctly when the sensor resumes).

The serializer creates the i2c adapter to which the sensor is added, so, 
afaics, there should be a child-parent relationship there. But maybe I 
have something wrong there, or it just doesn't work as I imagine it 
would work.

  Tomi
Laurent Pinchart Feb. 9, 2023, 10:54 a.m. UTC | #17
Hi Tomi,

On Wed, Feb 08, 2023 at 05:10:05PM +0200, Tomi Valkeinen wrote:
> On 27/01/2023 11:15, Andy Shevchenko wrote:
> > On Fri, Jan 27, 2023 at 10:24:04AM +0200, Tomi Valkeinen wrote:
> >> On 26/01/2023 12:51, Laurent Pinchart wrote:
> >>> On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote:
> >>>> On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote:
> >>>>> On 25/01/2023 17:27, Andy Shevchenko wrote:
> > 
> > ...
> > 
> >>>>>> But I probably don't understand the ATR structure and what exactly we need to
> >>>>>> pass to it, perhaps it also can be replaced with properties (note, that we have
> >>>>>> some interesting ones that called references, which is an alternative to DT
> >>>>>> phandle).
> >>>>>
> >>>>> Well, maybe this needs a Linux bus implementation. I'm not that familiar
> >>>>> with implementing a bus, but I think that would make it easier to share data
> >>>>> between the deserializer and the serializer. A bus sounds a bit like an
> >>>>> overkill for a 1-to-1 connection, used by a few drivers, but maybe it
> >>>>> wouldn't be too much code.
> >>>>
> >>>> Have you looked at auxiliary bus (appeared a few releases ago in kernel)?
> >>>
> >>> As far as I understand, the auxiliary bus infrastructure is meant for
> >>> use cases where a single hardware device needs to be split into multiple
> >>> logical devices (as in struct device). Platform devices were
> >>> historically (ab)used for this, and the auxiliary bus is meant as a
> >>> cleaner solution. I'm not sure if it would be a good match here, or if
> >>> it would be considered an abuse of the auxiliary bus API.
> >>
> >> The aux bus docs say "A key requirement for utilizing the auxiliary bus is
> >> that there is no dependency on a physical bus, device, register accesses or
> >> regmap support. These individual devices split from the core cannot live on
> >> the platform bus as they are not physical devices that are controlled by
> >> DT/ACPI.", which doesn't sound like a good fit.
> > 
> > Thanks for checking!
> > 
> >> The deserializer and serializers are currently independent devices and
> >> drivers (the pdata is the only shared thing), but I think we may need
> >> something better here. The devices are more tightly tied together than
> >> "normal" video devices, in my opinion, as the serializer is fully controlled
> >> by the deserializer (including power).
> >>
> >> And if we ever want to implement something like power management, we
> >> probably need something more than what we have now. Although I don't know
> >> how that would be done, as all the peripherals behind the serializer would
> >> also lose power...
> > 
> > I believe you have to create a power domain for them and when such device
> > is added, the power domain of it should belong to the serialized.
> 
> I was testing this, and got something working.

As discussed offline, I'm not sure power domains are the right tool for
this. I would model the power supplies as regulators, provided by the
deserializer, and acquired by the serializers. If the devices on the
remote side are all children of the serializer (which I think they
should be), then enabling the regulator in the PM resume handler of the
serializer should be all you need.

> I have the deserializer introducing a separate power-domain for each RX 
> port, and the serializer and the sensor both refer to their port's 
> domain. I can see that the deserializer gets power on/off callbacks 
> correctly when either serializer or sensor resumes.
> 
> The problem I have now is that while the power comes from the 
> deserializer and is thus covered with the power domain, the sensor uses 
> services from the serializer (gpios, clocks, i2c bus), and the 
> serializer is not woken up when the sensor does runtime-pm resume (the 
> power domain is powered up correctly when the sensor resumes).

Is the sensor not a child of the serializer ?

> The serializer creates the i2c adapter to which the sensor is added, so, 
> afaics, there should be a child-parent relationship there. But maybe I 
> have something wrong there, or it just doesn't work as I imagine it 
> would work.

You can check the parent/child relationships fairly easily in sysfs.
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index ba716f2861cf..d0dc8572191d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20626,6 +20626,14 @@  F:	drivers/misc/tifm*
 F:	drivers/mmc/host/tifm_sd.c
 F:	include/linux/tifm.h
 
+TI FPD-LINK DRIVERS
+M:	Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
+L:	linux-media@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/media/i2c/ti,ds90*
+F:	drivers/media/i2c/ds90*
+F:	include/media/i2c/ds90*
+
 TI KEYSTONE MULTICORE NAVIGATOR DRIVERS
 M:	Nishanth Menon <nm@ti.com>
 M:	Santosh Shilimkar <ssantosh@kernel.org>
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 7806d4b81716..dc1c7c80dc1c 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -1595,4 +1595,25 @@  config VIDEO_THS7303
 
 endmenu
 
+#
+# Video serializers and deserializers (e.g. FPD-Link)
+#
+
+menu "Video serializers and deserializers"
+
+config VIDEO_DS90UB960
+	tristate "TI FPD-Link III/IV Deserializers"
+	depends on OF && I2C && VIDEO_DEV
+	select I2C_ATR
+	select MEDIA_CONTROLLER
+	select OF_GPIO
+	select REGMAP_I2C
+	select V4L2_FWNODE
+	select VIDEO_V4L2_SUBDEV_API
+	help
+	  Device driver for the Texas Instruments DS90UB960
+	  FPD-Link III Deserializer and DS90UB9702 FPD-Link IV Deserializer.
+
+endmenu
+
 endif # VIDEO_DEV
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 0a2933103dd9..4cd680f3b953 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -142,3 +142,4 @@  obj-$(CONFIG_VIDEO_VPX3220) += vpx3220.o
 obj-$(CONFIG_VIDEO_VS6624) += vs6624.o
 obj-$(CONFIG_VIDEO_WM8739) += wm8739.o
 obj-$(CONFIG_VIDEO_WM8775) += wm8775.o
+obj-$(CONFIG_VIDEO_DS90UB960)	+= ds90ub960.o
diff --git a/drivers/media/i2c/ds90ub960.c b/drivers/media/i2c/ds90ub960.c
new file mode 100644
index 000000000000..2cefb3744901
--- /dev/null
+++ b/drivers/media/i2c/ds90ub960.c
@@ -0,0 +1,4254 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the Texas Instruments DS90UB960-Q1 video deserializer
+ *
+ * Copyright (c) 2019 Luca Ceresoli <luca@lucaceresoli.net>
+ * Copyright (c) 2023 Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/fwnode.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c-atr.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include <media/i2c/ds90ub9xx.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-subdev.h>
+
+#define UB960_POLL_TIME_MS	500
+
+#define UB960_MAX_RX_NPORTS	4
+#define UB960_MAX_TX_NPORTS	2
+#define UB960_MAX_NPORTS	(UB960_MAX_RX_NPORTS + UB960_MAX_TX_NPORTS)
+
+#define UB960_MAX_PORT_ALIASES	8
+#define UB960_MAX_POOL_ALIASES	(UB960_MAX_RX_NPORTS * UB960_MAX_PORT_ALIASES)
+
+#define UB960_NUM_BC_GPIOS		4
+
+/*
+ * Register map
+ *
+ * 0x00-0x32   Shared (UB960_SR)
+ * 0x33-0x3A   CSI-2 TX (per-port paged on DS90UB960, shared on 954) (UB960_TR)
+ * 0x4C        Shared (UB960_SR)
+ * 0x4D-0x7F   FPD-Link RX, per-port paged (UB960_RR)
+ * 0xB0-0xBF   Shared (UB960_SR)
+ * 0xD0-0xDF   FPD-Link RX, per-port paged (UB960_RR)
+ * 0xF0-0xF5   Shared (UB960_SR)
+ * 0xF8-0xFB   Shared (UB960_SR)
+ * All others  Reserved
+ *
+ * Register prefixes:
+ * UB960_SR_* = Shared register
+ * UB960_RR_* = FPD-Link RX, per-port paged register
+ * UB960_TR_* = CSI-2 TX, per-port paged register
+ * UB960_XR_* = Reserved register
+ * UB960_IR_* = Indirect register
+ */
+
+#define UB960_SR_I2C_DEV_ID			0x00
+#define UB960_SR_RESET				0x01
+#define UB960_SR_RESET_DIGITAL_RESET1		BIT(1)
+#define UB960_SR_RESET_DIGITAL_RESET0		BIT(0)
+#define UB960_SR_RESET_GPIO_LOCK_RELEASE	BIT(5)
+
+#define UB960_SR_GEN_CONFIG			0x02
+#define UB960_SR_REV_MASK			0x03
+#define UB960_SR_DEVICE_STS			0x04
+#define UB960_SR_PAR_ERR_THOLD_HI		0x05
+#define UB960_SR_PAR_ERR_THOLD_LO		0x06
+#define UB960_SR_BCC_WDOG_CTL			0x07
+#define UB960_SR_I2C_CTL1			0x08
+#define UB960_SR_I2C_CTL2			0x09
+#define UB960_SR_SCL_HIGH_TIME			0x0A
+#define UB960_SR_SCL_LOW_TIME			0x0B
+#define UB960_SR_RX_PORT_CTL			0x0C
+#define UB960_SR_IO_CTL				0x0D
+#define UB960_SR_GPIO_PIN_STS			0x0E
+#define UB960_SR_GPIO_INPUT_CTL			0x0F
+#define UB960_SR_GPIO_PIN_CTL(n)		(0x10 + (n)) /* n < UB960_NUM_GPIOS */
+#define UB960_SR_GPIO_PIN_CTL_GPIO_OUT_SEL		5
+#define UB960_SR_GPIO_PIN_CTL_GPIO_OUT_SRC_SHIFT	2
+#define UB960_SR_GPIO_PIN_CTL_GPIO_OUT_EN		BIT(0)
+
+#define UB960_SR_FS_CTL				0x18
+#define UB960_SR_FS_HIGH_TIME_1			0x19
+#define UB960_SR_FS_HIGH_TIME_0			0x1A
+#define UB960_SR_FS_LOW_TIME_1			0x1B
+#define UB960_SR_FS_LOW_TIME_0			0x1C
+#define UB960_SR_MAX_FRM_HI			0x1D
+#define UB960_SR_MAX_FRM_LO			0x1E
+#define UB960_SR_CSI_PLL_CTL			0x1F
+
+#define UB960_SR_FWD_CTL1			0x20
+#define UB960_SR_FWD_CTL1_PORT_DIS(n)		BIT((n) + 4)
+
+#define UB960_SR_FWD_CTL2			0x21
+#define UB960_SR_FWD_STS			0x22
+
+#define UB960_SR_INTERRUPT_CTL			0x23
+#define UB960_SR_INTERRUPT_CTL_INT_EN		BIT(7)
+#define UB960_SR_INTERRUPT_CTL_IE_CSI_TX0	BIT(4)
+#define UB960_SR_INTERRUPT_CTL_IE_RX(n)		BIT((n)) /* rxport[n] IRQ */
+#define UB960_SR_INTERRUPT_CTL_ALL		0x83 /* TODO 0x93 to enable CSI */
+
+#define UB960_SR_INTERRUPT_STS			0x24
+#define UB960_SR_INTERRUPT_STS_INT		BIT(7)
+#define UB960_SR_INTERRUPT_STS_IS_CSI_TX(n)	BIT(4 + (n)) /* txport[n] IRQ */
+#define UB960_SR_INTERRUPT_STS_IS_RX(n)		BIT((n)) /* rxport[n] IRQ */
+
+#define UB960_SR_TS_CONFIG			0x25
+#define UB960_SR_TS_CONTROL			0x26
+#define UB960_SR_TS_LINE_HI			0x27
+#define UB960_SR_TS_LINE_LO			0x28
+#define UB960_SR_TS_STATUS			0x29
+#define UB960_SR_TIMESTAMP_P0_HI		0x2A
+#define UB960_SR_TIMESTAMP_P0_LO		0x2B
+#define UB960_SR_TIMESTAMP_P1_HI		0x2C
+#define UB960_SR_TIMESTAMP_P1_LO		0x2D
+
+#define UB960_SR_CSI_PORT_SEL			0x32
+
+#define UB960_TR_CSI_CTL			0x33
+#define UB960_TR_CSI_CTL_CSI_CAL_EN		BIT(6)
+#define UB960_TR_CSI_CTL_CSI_ENABLE		BIT(0)
+
+#define UB960_TR_CSI_CTL2			0x34
+#define UB960_TR_CSI_STS			0x35
+#define UB960_TR_CSI_TX_ICR			0x36
+
+#define UB960_TR_CSI_TX_ISR			0x37
+#define UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR	BIT(3)
+#define UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR	BIT(1)
+
+#define UB960_TR_CSI_TEST_CTL			0x38
+#define UB960_TR_CSI_TEST_PATT_HI		0x39
+#define UB960_TR_CSI_TEST_PATT_LO		0x3A
+
+#define UB960_XR_SFILTER_CFG			0x41
+#define UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT	4
+#define UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT	0
+
+#define UB960_XR_AEQ_CTL1			0x42
+#define UB960_XR_AEQ_CTL1_AEQ_ERR_CTL_SHIFT	4
+#define UB960_XR_AEQ_CTL1_AEQ_SFILTER_EN	BIT(0)
+
+#define UB960_XR_AEQ_ERR_THOLD			0x43
+
+#define UB960_RR_BCC_ERR_CTL			0x46
+#define UB960_RR_BCC_STATUS			0x47
+#define UB960_RR_BCC_STATUS_SEQ_ERROR		BIT(5)
+#define UB960_RR_BCC_STATUS_MASTER_ERR		BIT(4)
+#define UB960_RR_BCC_STATUS_MASTER_TO		BIT(3)
+#define UB960_RR_BCC_STATUS_SLAVE_ERR		BIT(2)
+#define UB960_RR_BCC_STATUS_SLAVE_TO		BIT(1)
+#define UB960_RR_BCC_STATUS_RESP_ERR		BIT(0)
+
+#define UB960_RR_FPD3_CAP			0x4A
+#define UB960_RR_RAW_EMBED_DTYPE		0x4B
+
+#define UB960_SR_FPD3_PORT_SEL			0x4C
+
+#define UB960_RR_RX_PORT_STS1			0x4D
+#define UB960_RR_RX_PORT_STS1_BCC_CRC_ERROR	BIT(5)
+#define UB960_RR_RX_PORT_STS1_LOCK_STS_CHG	BIT(4)
+#define UB960_RR_RX_PORT_STS1_BCC_SEQ_ERROR	BIT(3)
+#define UB960_RR_RX_PORT_STS1_PARITY_ERROR	BIT(2)
+#define UB960_RR_RX_PORT_STS1_PORT_PASS		BIT(1)
+#define UB960_RR_RX_PORT_STS1_LOCK_STS		BIT(0)
+
+#define UB960_RR_RX_PORT_STS2			0x4E
+#define UB960_RR_RX_PORT_STS2_LINE_LEN_UNSTABLE	BIT(7)
+#define UB960_RR_RX_PORT_STS2_LINE_LEN_CHG	BIT(6)
+#define UB960_RR_RX_PORT_STS2_FPD3_ENCODE_ERROR	BIT(5)
+#define UB960_RR_RX_PORT_STS2_BUFFER_ERROR	BIT(4)
+#define UB960_RR_RX_PORT_STS2_CSI_ERROR		BIT(3)
+#define UB960_RR_RX_PORT_STS2_FREQ_STABLE	BIT(2)
+#define UB960_RR_RX_PORT_STS2_CABLE_FAULT	BIT(1)
+#define UB960_RR_RX_PORT_STS2_LINE_CNT_CHG	BIT(0)
+
+#define UB960_RR_RX_FREQ_HIGH			0x4F
+#define UB960_RR_RX_FREQ_LOW			0x50
+#define UB960_RR_SENSOR_STS_0			0x51
+#define UB960_RR_SENSOR_STS_1			0x52
+#define UB960_RR_SENSOR_STS_2			0x53
+#define UB960_RR_SENSOR_STS_3			0x54
+#define UB960_RR_RX_PAR_ERR_HI			0x55
+#define UB960_RR_RX_PAR_ERR_LO			0x56
+#define UB960_RR_BIST_ERR_COUNT			0x57
+
+#define UB960_RR_BCC_CONFIG			0x58
+#define UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH	BIT(6)
+
+#define UB960_RR_DATAPATH_CTL1			0x59
+#define UB960_RR_DATAPATH_CTL2			0x5A
+#define UB960_RR_SER_ID				0x5B
+#define UB960_RR_SER_ALIAS_ID			0x5C
+
+/* For these two register sets: n < UB960_MAX_PORT_ALIASES */
+#define UB960_RR_SLAVE_ID(n)			(0x5D + (n))
+#define UB960_RR_SLAVE_ALIAS(n)			(0x65 + (n))
+
+#define UB960_RR_PORT_CONFIG			0x6D
+#define UB960_RR_BC_GPIO_CTL(n)			(0x6E + (n)) /* n < 2 */
+#define UB960_RR_RAW10_ID			0x70
+#define UB960_RR_RAW12_ID			0x71
+#define UB960_RR_CSI_VC_MAP			0x72
+#define UB960_RR_LINE_COUNT_HI			0x73
+#define UB960_RR_LINE_COUNT_LO			0x74
+#define UB960_RR_LINE_LEN_1			0x75
+#define UB960_RR_LINE_LEN_0			0x76
+#define UB960_RR_FREQ_DET_CTL			0x77
+#define UB960_RR_MAILBOX_1			0x78
+#define UB960_RR_MAILBOX_2			0x79
+
+#define UB960_RR_CSI_RX_STS			0x7A
+#define UB960_RR_CSI_RX_STS_LENGTH_ERR		BIT(3)
+#define UB960_RR_CSI_RX_STS_CKSUM_ERR		BIT(2)
+#define UB960_RR_CSI_RX_STS_ECC2_ERR		BIT(1)
+#define UB960_RR_CSI_RX_STS_ECC1_ERR		BIT(0)
+
+#define UB960_RR_CSI_ERR_COUNTER		0x7B
+#define UB960_RR_PORT_CONFIG2			0x7C
+#define UB960_RR_PORT_CONFIG2_LV_POL_LOW	BIT(1)
+#define UB960_RR_PORT_CONFIG2_FV_POL_LOW	BIT(0)
+
+#define UB960_RR_PORT_PASS_CTL			0x7D
+#define UB960_RR_SEN_INT_RISE_CTL		0x7E
+#define UB960_RR_SEN_INT_FALL_CTL		0x7F
+
+#define UB960_SR_CSI_FRAME_COUNT_HI(n)		(0x90 + 8 * (n))
+#define UB960_SR_CSI_FRAME_COUNT_LO(n)		(0x91 + 8 * (n))
+#define UB960_SR_CSI_FRAME_ERR_COUNT_HI(n)	(0x92 + 8 * (n))
+#define UB960_SR_CSI_FRAME_ERR_COUNT_LO(n)	(0x93 + 8 * (n))
+#define UB960_SR_CSI_LINE_COUNT_HI(n)		(0x94 + 8 * (n))
+#define UB960_SR_CSI_LINE_COUNT_LO(n)		(0x95 + 8 * (n))
+#define UB960_SR_CSI_LINE_ERR_COUNT_HI(n)	(0x96 + 8 * (n))
+#define UB960_SR_CSI_LINE_ERR_COUNT_LO(n)	(0x97 + 8 * (n))
+
+#define UB960_XR_REFCLK_FREQ			0xA5	/* UB960 */
+
+#define UB960_RR_VC_ID_MAP(x)			(0xa0 + (x)) /* UB9702 */
+
+#define UB960_SR_IND_ACC_CTL			0xB0
+#define UB960_SR_IND_ACC_CTL_IA_AUTO_INC	BIT(1)
+
+#define UB960_SR_IND_ACC_ADDR			0xB1
+#define UB960_SR_IND_ACC_DATA			0xB2
+#define UB960_SR_BIST_CONTROL			0xB3
+#define UB960_SR_MODE_IDX_STS			0xB8
+#define UB960_SR_LINK_ERROR_COUNT		0xB9
+#define UB960_SR_FPD3_ENC_CTL			0xBA
+#define UB960_SR_FV_MIN_TIME			0xBC
+#define UB960_SR_GPIO_PD_CTL			0xBE
+
+#define UB960_SR_FPD_RATE_CFG			0xc2	/* UB9702 */
+#define UB960_SR_CSI_PLL_DIV			0xc9	/* UB9702 */
+
+#define UB960_RR_PORT_DEBUG			0xD0
+#define UB960_RR_AEQ_CTL2			0xD2
+#define UB960_RR_AEQ_CTL2_SET_AEQ_FLOOR		BIT(2)
+
+#define UB960_RR_AEQ_STATUS			0xD3
+
+#define UB960_RR_AEQ_BYPASS			0xD4
+#define UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT	5
+#define UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK	GENMASK(7, 5)
+#define UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT	1
+#define UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK	GENMASK(3, 1)
+#define UB960_RR_AEQ_BYPASS_ENABLE			BIT(0)
+
+#define UB960_RR_AEQ_MIN_MAX			0xD5
+#define UB960_RR_AEQ_MIN_MAX_AEQ_MAX_SHIFT	4
+#define UB960_RR_AEQ_MIN_MAX_AEQ_FLOOR_SHIFT	0
+
+#define UB960_RR_SFILTER_STS_0			0xD6
+#define UB960_RR_SFILTER_STS_1			0xD7
+#define UB960_RR_PORT_ICR_HI			0xD8
+#define UB960_RR_PORT_ICR_LO			0xD9
+#define UB960_RR_PORT_ISR_HI			0xDA
+#define UB960_RR_PORT_ISR_LO			0xDB
+#define UB960_RR_FC_GPIO_STS			0xDC
+#define UB960_RR_FC_GPIO_ICR			0xDD
+#define UB960_RR_SEN_INT_RISE_STS		0xDE
+#define UB960_RR_SEN_INT_FALL_STS		0xDF
+
+#define UB960_RR_CHANNEL_MODE			0xe4	/* UB9702 */
+
+#define UB960_SR_FPD3_RX_ID(n)			(0xF0 + (n))
+
+#define UB960_SR_I2C_RX_ID(n)			(0xF8 + (n)) /* < UB960_FPD_RX_NPORTS */
+
+/* Indirect register blocks */
+#define UB960_IND_TARGET_PAT_GEN		0x00
+#define UB960_IND_TARGET_RX_ANA(n)		(0x01 + (n))
+#define UB960_IND_TARGET_CSI_CSIPLL_REG_1	0x92	/* UB9702 */
+#define UB960_IND_TARGET_CSI_ANA		0x07
+
+/* UB960_IR_PGEN_*: Indirect Registers for Test Pattern Generator */
+
+#define UB960_IR_PGEN_CTL			0x01
+#define UB960_IR_PGEN_CTL_PGEN_ENABLE		BIT(0)
+
+#define UB960_IR_PGEN_CFG			0x02
+#define UB960_IR_PGEN_CSI_DI			0x03
+#define UB960_IR_PGEN_LINE_SIZE1		0x04
+#define UB960_IR_PGEN_LINE_SIZE0		0x05
+#define UB960_IR_PGEN_BAR_SIZE1			0x06
+#define UB960_IR_PGEN_BAR_SIZE0			0x07
+#define UB960_IR_PGEN_ACT_LPF1			0x08
+#define UB960_IR_PGEN_ACT_LPF0			0x09
+#define UB960_IR_PGEN_TOT_LPF1			0x0A
+#define UB960_IR_PGEN_TOT_LPF0			0x0B
+#define UB960_IR_PGEN_LINE_PD1			0x0C
+#define UB960_IR_PGEN_LINE_PD0			0x0D
+#define UB960_IR_PGEN_VBP			0x0E
+#define UB960_IR_PGEN_VFP			0x0F
+#define UB960_IR_PGEN_COLOR(n)			(0x10 + (n)) /* n < 15 */
+
+#define UB960_IR_RX_ANA_STROBE_SET_CLK		0x08
+#define UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY	BIT(3)
+#define UB960_IR_RX_ANA_STROBE_SET_CLK_DELAY_MASK	GENMASK(2, 0)
+
+#define UB960_IR_RX_ANA_STROBE_SET_DATA		0x09
+#define UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY	BIT(3)
+#define UB960_IR_RX_ANA_STROBE_SET_DATA_DELAY_MASK	GENMASK(2, 0)
+
+/* EQ related */
+
+#define UB960_MIN_AEQ_STROBE_POS -7
+#define UB960_MAX_AEQ_STROBE_POS 7
+
+#define UB960_MIN_MANUAL_STROBE_POS -(7 + 6)
+#define UB960_MAX_MANUAL_STROBE_POS (7 + 6)
+#define UB960_NUM_MANUAL_STROBE_POS (UB960_MAX_MANUAL_STROBE_POS - UB960_MIN_MANUAL_STROBE_POS + 1)
+
+#define UB960_MIN_EQ_LEVEL 0
+#define UB960_MAX_EQ_LEVEL 14
+#define UB960_NUM_EQ_LEVELS (UB960_MAX_EQ_LEVEL - UB960_MIN_EQ_LEVEL + 1)
+
+struct ub960_hw_data {
+	const char *model;
+	u8 num_rxports;
+	u8 num_txports;
+	bool is_ub9702;
+	bool is_fpdlink4;
+};
+
+enum ub960_rxport_mode {
+	RXPORT_MODE_RAW10 = 0,
+	RXPORT_MODE_RAW12_HF = 1,
+	RXPORT_MODE_RAW12_LF = 2,
+	RXPORT_MODE_CSI2_SYNC = 3,
+	RXPORT_MODE_CSI2_ASYNC = 4,
+	RXPORT_MODE_LAST = RXPORT_MODE_CSI2_ASYNC,
+};
+
+enum ub960_rxport_cdr {
+	RXPORT_CDR_FPD3 = 0,
+	RXPORT_CDR_FPD4 = 1,
+	RXPORT_CDR_LAST = RXPORT_CDR_FPD4,
+};
+
+struct ub960_rxport {
+	struct ub960_data      *priv;
+	u8                      nport;	/* RX port number, and index in priv->rxport[] */
+
+	struct v4l2_subdev     *source_sd;	/* Connected subdev */
+	u16			source_sd_pad;
+	struct fwnode_handle   *source_ep_fwnode;
+
+	enum ub960_rxport_mode  rx_mode;
+	enum ub960_rxport_cdr	cdr_mode;
+
+	struct fwnode_handle   *remote_fwnode;	/* 'serializer' fwnode */
+	struct i2c_client      *ser_client;	/* Serializer */
+	unsigned short          ser_alias;	/* Serializer i2c alias (lower 7 bits) */
+
+	u8			lv_fv_pol;	/* LV and FV polarities */
+
+	struct regulator	*vpoc;
+
+	/* EQ settings */
+	struct {
+		bool manual_eq;
+
+		s8 strobe_pos;
+
+		union {
+			struct {
+				u8 eq_level_min;
+				u8 eq_level_max;
+			} aeq;
+
+			struct {
+				u8 eq_level;
+			} manual;
+		};
+	} eq;
+
+	struct ds90ub9xx_platform_data ser_platform_data;
+};
+
+struct ub960_asd {
+	struct v4l2_async_subdev base;
+	struct ub960_rxport *rxport;
+};
+
+static inline struct ub960_asd *to_ub960_asd(struct v4l2_async_subdev *asd)
+{
+	return container_of(asd, struct ub960_asd, base);
+}
+
+struct ub960_txport {
+	struct ub960_data      *priv;
+	u8                      nport;	/* TX port number, and index in priv->txport[] */
+
+	u32 num_data_lanes;
+};
+
+struct atr_alias_table_entry {
+	u16 alias_id;	/* Alias ID from DT */
+
+	bool reserved;
+	u8 nport;
+	u8 slave_id;	/* i2c client's local i2c address */
+	u8 port_reg_idx;
+};
+
+struct atr_alias_table {
+	/* Protects fields in this struct */
+	struct mutex lock;
+
+	size_t num_entries;
+	struct atr_alias_table_entry *entries;
+};
+
+struct ub960_data {
+	const struct ub960_hw_data	*hw_data;
+	struct i2c_client	*client; /* for shared local registers */
+	struct regmap		*regmap;
+
+	/* lock for register access */
+	struct mutex		reg_lock;
+
+	struct clk		*refclk;
+
+	struct regulator	*vddio;
+
+	struct gpio_desc	*pd_gpio;
+	struct delayed_work	poll_work;
+	struct i2c_atr		*atr;
+	struct ub960_rxport	*rxports[UB960_MAX_RX_NPORTS];
+	struct ub960_txport	*txports[UB960_MAX_TX_NPORTS];
+
+	struct v4l2_subdev	sd;
+	struct media_pad	pads[UB960_MAX_NPORTS];
+
+	struct v4l2_ctrl_handler   ctrl_handler;
+	struct v4l2_async_notifier notifier;
+
+	u32 tx_data_rate;		/* Nominal data rate (Gb/s) */
+	s64 tx_link_freq[1];
+
+	struct atr_alias_table	atr_alias_table;
+
+	u8 current_read_rxport;
+	u8 current_write_rxport_mask;
+
+	u8 current_read_csiport;
+	u8 current_write_csiport_mask;
+
+	u8 current_indirect_target;
+
+	bool streaming;
+
+	u8 stored_fwd_ctl;
+
+	u64 stream_enable_mask[UB960_MAX_NPORTS];
+
+	/* These are common to all ports */
+	struct {
+		bool manual;
+
+		s8 min;
+		s8 max;
+	} strobe;
+};
+
+static void ub960_reset(struct ub960_data *priv, bool reset_regs);
+
+static inline struct ub960_data *sd_to_ub960(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct ub960_data, sd);
+}
+
+enum {
+	TEST_PATTERN_DISABLED = 0,
+	TEST_PATTERN_V_COLOR_BARS_1,
+	TEST_PATTERN_V_COLOR_BARS_2,
+	TEST_PATTERN_V_COLOR_BARS_4,
+	TEST_PATTERN_V_COLOR_BARS_8,
+};
+
+static const char *const ub960_tpg_qmenu[] = {
+	"Disabled",
+	"1 vertical color bar",
+	"2 vertical color bars",
+	"4 vertical color bars",
+	"8 vertical color bars",
+};
+
+static inline bool ub960_pad_is_sink(struct ub960_data *priv, u32 pad)
+{
+	return pad < priv->hw_data->num_rxports;
+}
+
+static inline bool ub960_pad_is_source(struct ub960_data *priv, u32 pad)
+{
+	return pad >= priv->hw_data->num_rxports &&
+	       pad < (priv->hw_data->num_rxports + priv->hw_data->num_txports);
+}
+
+static inline unsigned int ub960_pad_to_port(struct ub960_data *priv, u32 pad)
+{
+	if (ub960_pad_is_sink(priv, pad))
+		return pad;
+	else
+		return pad - priv->hw_data->num_rxports;
+}
+
+struct ub960_format_info {
+	u32 code;
+	u32 bpp;
+	u8 datatype;
+	bool meta;
+};
+
+static const struct ub960_format_info ub960_formats[] = {
+	{ .code = MEDIA_BUS_FMT_YUYV8_1X16, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_UYVY8_1X16, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_VYUY8_1X16, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_YVYU8_1X16, .bpp = 16, .datatype = 0x1e, },
+
+	/* Legacy */
+	{ .code = MEDIA_BUS_FMT_YUYV8_2X8, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_UYVY8_2X8, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_VYUY8_2X8, .bpp = 16, .datatype = 0x1e, },
+	{ .code = MEDIA_BUS_FMT_YVYU8_2X8, .bpp = 16, .datatype = 0x1e, },
+
+	/* RAW */
+	{ .code = MEDIA_BUS_FMT_SBGGR12_1X12, .bpp = 12, .datatype = 0x2c, },
+	{ .code = MEDIA_BUS_FMT_SRGGB12_1X12, .bpp = 12, .datatype = 0x2c, },
+};
+
+static const struct ub960_format_info *ub960_find_format(u32 code)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(ub960_formats); ++i) {
+		if (ub960_formats[i].code == code)
+			return &ub960_formats[i];
+	}
+
+	return NULL;
+}
+
+/* -----------------------------------------------------------------------------
+ * Basic device access
+ */
+
+static int ub960_read(struct ub960_data *priv, u8 reg, u8 *val)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int v;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = regmap_read(priv->regmap, reg, &v);
+	if (ret)
+		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+	else
+		*val = v;
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_write(struct ub960_data *priv, u8 reg, u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = regmap_write(priv->regmap, reg, val);
+	if (ret)
+		dev_err(dev, "%s: cannot write register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_update_bits(struct ub960_data *priv, u8 reg, u8 mask, u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = regmap_update_bits(priv->regmap, reg, mask, val);
+	if (ret)
+		dev_err(dev, "%s: cannot update register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int _ub960_rxport_select(struct ub960_data *priv, u8 nport)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	if (priv->current_read_rxport == nport &&
+	    priv->current_write_rxport_mask == BIT(nport))
+		return 0;
+
+	ret = regmap_write(priv->regmap, UB960_SR_FPD3_PORT_SEL,
+			   (nport << 4) | (1 << nport));
+	if (ret) {
+		dev_err(dev, "%s: cannot select rxport %d (%d)!\n", __func__,
+			nport, ret);
+		return ret;
+	}
+
+	priv->current_read_rxport = nport;
+	priv->current_write_rxport_mask = BIT(nport);
+
+	return 0;
+}
+
+static int ub960_rxport_read(struct ub960_data *priv, u8 nport, u8 reg, u8 *val)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int v;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_rxport_select(priv, nport);
+
+	ret = regmap_read(priv->regmap, reg, &v);
+	if (ret)
+		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+	else
+		*val = v;
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_rxport_write(struct ub960_data *priv, u8 nport, u8 reg, u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_rxport_select(priv, nport);
+
+	ret = regmap_write(priv->regmap, reg, val);
+	if (ret)
+		dev_err(dev, "%s: cannot write register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_rxport_update_bits(struct ub960_data *priv, u8 nport, u8 reg,
+				    u8 mask, u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_rxport_select(priv, nport);
+
+	ret = regmap_update_bits(priv->regmap, reg, mask, val);
+
+	if (ret)
+		dev_err(dev, "%s: cannot update register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int _ub960_csiport_select(struct ub960_data *priv, u8 nport)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	if (priv->current_read_csiport == nport &&
+	    priv->current_write_csiport_mask == BIT(nport))
+		return 0;
+
+	ret = regmap_write(priv->regmap, UB960_SR_CSI_PORT_SEL,
+			   (nport << 4) | (1 << nport));
+	if (ret) {
+		dev_err(dev, "%s: cannot select csi port %d (%d)!\n", __func__,
+			nport, ret);
+		return ret;
+	}
+
+	priv->current_read_csiport = nport;
+	priv->current_write_csiport_mask = BIT(nport);
+
+	return 0;
+}
+
+static int ub960_csiport_read(struct ub960_data *priv, u8 nport, u8 reg,
+			      u8 *val)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int v;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_csiport_select(priv, nport);
+
+	ret = regmap_read(priv->regmap, reg, &v);
+	if (ret)
+		dev_err(dev, "%s: cannot read register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+	else
+		*val = v;
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_csiport_write(struct ub960_data *priv, u8 nport, u8 reg,
+			       u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_csiport_select(priv, nport);
+
+	ret = regmap_write(priv->regmap, reg, val);
+	if (ret)
+		dev_err(dev, "%s: cannot write register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_csiport_update_bits(struct ub960_data *priv, u8 nport, u8 reg,
+				     u8 mask, u8 val)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	_ub960_csiport_select(priv, nport);
+
+	ret = regmap_update_bits(priv->regmap, reg, mask, val);
+
+	if (ret)
+		dev_err(dev, "%s: cannot update register 0x%02x (%d)!\n",
+			__func__, reg, ret);
+
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int _ub960_select_ind_reg_block(struct ub960_data *priv, u8 block)
+{
+	struct device *dev = &priv->client->dev;
+	int ret;
+
+	if (priv->current_indirect_target == block)
+		return 0;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_CTL, block << 2);
+	if (ret) {
+		dev_err(dev, "%s: cannot select indirect target %u (%d)!\n",
+			__func__, block, ret);
+		return ret;
+	}
+
+	priv->current_indirect_target = block;
+
+	return 0;
+}
+
+static int ub960_read_ind(struct ub960_data *priv, u8 block, u8 reg, u8 *val)
+{
+	unsigned int v;
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = _ub960_select_ind_reg_block(priv, block);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_ADDR, reg);
+	if (ret) {
+		dev_err(&priv->client->dev,
+			"Write to IND_ACC_ADDR failed when reading %u:%x02x: %d\n",
+			block, reg, ret);
+		goto out;
+	}
+
+	ret = regmap_read(priv->regmap, UB960_SR_IND_ACC_DATA, &v);
+	if (ret) {
+		dev_err(&priv->client->dev,
+			"Write to IND_ACC_DATA failed when reading %u:%x02x: %d\n",
+			block, reg, ret);
+		goto out;
+	}
+
+	*val = v;
+
+out:
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_write_ind(struct ub960_data *priv, u8 block, u8 reg, u8 val)
+{
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = _ub960_select_ind_reg_block(priv, block);
+	if (ret) {
+		dev_err(&priv->client->dev,
+			"Write to IND_ACC_ADDR failed when writing %u:%x02x: %d\n",
+			block, reg, ret);
+		goto out;
+	}
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_ADDR, reg);
+	if (ret) {
+		dev_err(&priv->client->dev,
+			"Write to IND_ACC_DATA failed when writing %u:%x02x\n: %d\n",
+			block, reg, ret);
+		goto out;
+	}
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_DATA, val);
+
+out:
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_write_ind16(struct ub960_data *priv, u8 block, u8 reg, u16 val)
+{
+	int ret;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = _ub960_select_ind_reg_block(priv, block);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_ADDR, reg);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_DATA, val >> 8);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_ADDR, reg + 1);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_DATA, val & 0xff);
+	if (ret)
+		goto out;
+
+out:
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+static int ub960_ind_update_bits(struct ub960_data *priv, u8 block, u8 reg,
+				 u8 mask, u8 val)
+{
+	int ret;
+	u32 v;
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = _ub960_select_ind_reg_block(priv, block);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_ADDR, reg);
+	if (ret)
+		goto out;
+
+	ret = regmap_read(priv->regmap, UB960_SR_IND_ACC_DATA, &v);
+	if (ret)
+		goto out;
+
+	v &= ~mask;
+	v |= val;
+
+	ret = regmap_write(priv->regmap, UB960_SR_IND_ACC_DATA, v);
+
+out:
+	mutex_unlock(&priv->reg_lock);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * I2C-ATR (address translator)
+ */
+
+static int ub960_atr_attach_client(struct i2c_atr *atr, u32 chan_id,
+				   const struct i2c_client *client,
+				   u16 *alias_id)
+{
+	struct ub960_data *priv = i2c_atr_get_driver_data(atr);
+	struct ub960_rxport *rxport = priv->rxports[chan_id];
+	struct device *dev = &priv->client->dev;
+	struct atr_alias_table_entry *entry = NULL;
+	unsigned int reg_idx;
+	unsigned int pool_idx;
+	u16 alias;
+	int ret = 0;
+	u8 port_reg_idx_mask = 0;
+
+	dev_dbg(dev, "rx%u: %s\n", chan_id, __func__);
+
+	mutex_lock(&priv->atr_alias_table.lock);
+
+	/*
+	 * Go through the alias table and:
+	 *	1. Look for an unreserved entry
+	 *	2. Construct a bitmask of port's used alias entries
+	 */
+
+	for (pool_idx = 0; pool_idx < priv->atr_alias_table.num_entries; pool_idx++) {
+		struct atr_alias_table_entry *e;
+
+		e = &priv->atr_alias_table.entries[pool_idx];
+
+		if (!entry && !e->reserved)
+			entry = e;
+
+		if (e->reserved && e->nport == rxport->nport)
+			port_reg_idx_mask |= BIT(e->port_reg_idx);
+	}
+
+	if (!entry) {
+		dev_err(dev, "rx%u: alias pool exhausted\n", rxport->nport);
+		ret = -EADDRNOTAVAIL;
+		goto out;
+	}
+
+	if (port_reg_idx_mask == (1 << UB960_MAX_PORT_ALIASES) - 1) {
+		dev_err(dev, "rx%u: all aliases in use\n", rxport->nport);
+		ret = -EADDRNOTAVAIL;
+		goto out;
+	}
+
+	alias = entry->alias_id;
+
+	reg_idx = ffz(port_reg_idx_mask);
+
+	entry->reserved = true;
+	entry->nport = rxport->nport;
+	entry->slave_id = client->addr;
+	entry->port_reg_idx = reg_idx;
+
+	/* Map alias to slave */
+
+	ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ID(reg_idx),
+			   client->addr << 1);
+	ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx),
+			   alias << 1);
+
+	*alias_id = alias; /* tell the atr which alias we chose */
+
+	dev_dbg(dev, "rx%u: client 0x%02x mapped at alias 0x%02x (%s)\n",
+		rxport->nport, client->addr, alias, client->name);
+
+out:
+	mutex_unlock(&priv->atr_alias_table.lock);
+	return ret;
+}
+
+static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id,
+				    const struct i2c_client *client)
+{
+	struct ub960_data *priv = i2c_atr_get_driver_data(atr);
+	struct ub960_rxport *rxport = priv->rxports[chan_id];
+	struct device *dev = &priv->client->dev;
+	struct atr_alias_table_entry *entry;
+	unsigned int reg_idx;
+	unsigned int pool_idx;
+	u16 alias = 0;
+
+	dev_dbg(dev, "rx%u: %s\n", chan_id, __func__);
+
+	mutex_lock(&priv->atr_alias_table.lock);
+
+	/* Find alias mapped to this client */
+
+	for (pool_idx = 0; pool_idx < priv->atr_alias_table.num_entries; pool_idx++) {
+		entry = &priv->atr_alias_table.entries[pool_idx];
+
+		if (entry->reserved && entry->nport == rxport->nport &&
+		    entry->slave_id == client->addr)
+			break;
+	}
+
+	if (pool_idx == priv->atr_alias_table.num_entries) {
+		dev_err(dev, "rx%u: client 0x%02x is not mapped!\n",
+			rxport->nport, client->addr);
+		goto out;
+	}
+
+	alias = entry->alias_id;
+
+	reg_idx = entry->port_reg_idx;
+
+	/* Unmap */
+
+	ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx), 0);
+
+	entry->reserved = false;
+
+	dev_dbg(dev, "rx%u: client 0x%02x unmapped from alias 0x%02x (%s)\n",
+		rxport->nport, client->addr, alias, client->name);
+
+out:
+	mutex_unlock(&priv->atr_alias_table.lock);
+}
+
+static const struct i2c_atr_ops ub960_atr_ops = {
+	.attach_client = ub960_atr_attach_client,
+	.detach_client = ub960_atr_detach_client,
+};
+
+/* -----------------------------------------------------------------------------
+ * CSI ports
+ */
+
+static int ub960_parse_dt_txport(struct ub960_data *priv,
+				 const struct fwnode_handle *ep_fwnode,
+				 u8 nport)
+{
+	struct device *dev = &priv->client->dev;
+	struct ub960_txport *txport;
+	int ret;
+	u64 freq;
+
+	txport = kzalloc(sizeof(*txport), GFP_KERNEL);
+	if (!txport)
+		return -ENOMEM;
+
+	txport->priv = priv;
+	txport->nport = nport;
+
+	priv->txports[nport] = txport;
+
+	ret = fwnode_property_count_u32(ep_fwnode, "data-lanes");
+	if (ret <= 0) {
+		dev_err(dev, "tx%u: failed to parse 'data-lanes': %d\n", nport,
+			ret);
+		goto err_free_txport;
+	}
+
+	txport->num_data_lanes = ret;
+
+	ret = fwnode_property_count_u64(ep_fwnode, "link-frequencies");
+	if (ret < 0) {
+		dev_err(dev, "tx%u: failed to parse 'link-frequencies': %d\n",
+			nport, ret);
+		goto err_free_txport;
+	}
+
+	if (ret != 1) {
+		dev_err(dev,
+			"tx%u: 'link-frequencies' must contain a single frequency: %d\n",
+			nport, ret);
+		goto err_free_txport;
+	}
+
+	ret = fwnode_property_read_u64(ep_fwnode, "link-frequencies", &freq);
+	if (ret) {
+		dev_err(dev, "tx%u: failed to read 'link-frequencies': %d\n",
+			nport, ret);
+		goto err_free_txport;
+	}
+
+	priv->tx_link_freq[0] = freq;
+	priv->tx_data_rate = freq * 2;
+
+	if (priv->tx_data_rate != 1600000000 &&
+	    priv->tx_data_rate != 1200000000 &&
+	    priv->tx_data_rate != 800000000 &&
+	    priv->tx_data_rate != 400000000) {
+		dev_err(dev, "tx%u: invalid 'link-frequencies' value\n", nport);
+		return -EINVAL;
+	}
+
+	dev_dbg(dev, "tx%u: nominal data rate: %u", nport, priv->tx_data_rate);
+
+	return 0;
+
+err_free_txport:
+	kfree(txport);
+
+	return ret;
+}
+
+static void ub960_csi_handle_events(struct ub960_data *priv, u8 nport)
+{
+	struct device *dev = &priv->client->dev;
+	u8 csi_tx_isr;
+	int ret;
+
+	ret = ub960_csiport_read(priv, nport, UB960_TR_CSI_TX_ISR, &csi_tx_isr);
+
+	if (!ret) {
+		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_SYNC_ERROR)
+			dev_warn(dev, "TX%u: CSI_SYNC_ERROR\n", nport);
+
+		if (csi_tx_isr & UB960_TR_CSI_TX_ISR_IS_CSI_PASS_ERROR)
+			dev_warn(dev, "TX%u: CSI_PASS_ERROR\n", nport);
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * RX ports
+ */
+
+static int ub960_rxport_enable_vpocs(struct ub960_data *priv)
+{
+	unsigned int nport;
+	int ret;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport || !rxport->vpoc)
+			continue;
+
+		ret = regulator_enable(rxport->vpoc);
+		if (ret)
+			goto err_disable_vpocs;
+	}
+
+	return 0;
+
+err_disable_vpocs:
+	for (; nport > 0; --nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport - 1];
+
+		if (!rxport || !rxport->vpoc)
+			continue;
+
+		regulator_disable(rxport->vpoc);
+	}
+
+	return ret;
+}
+
+static void ub960_rxport_disable_vpocs(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport || !rxport->vpoc)
+			continue;
+
+		regulator_disable(rxport->vpoc);
+	}
+}
+
+static void ub960_rxport_clear_errors(struct ub960_data *priv,
+				      unsigned int nport)
+{
+	u8 v;
+
+	ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS1, &v);
+	ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS2, &v);
+	ub960_rxport_read(priv, nport, UB960_RR_CSI_RX_STS, &v);
+	ub960_rxport_read(priv, nport, UB960_RR_BCC_STATUS, &v);
+
+	ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v);
+	ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v);
+
+	ub960_rxport_read(priv, nport, UB960_RR_CSI_ERR_COUNTER, &v);
+}
+
+static void ub960_clear_rx_errors(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport)
+		ub960_rxport_clear_errors(priv, nport);
+}
+
+static int ub960_rxport_get_strobe_pos(struct ub960_data *priv,
+				       unsigned int nport, s8 *strobe_pos)
+{
+	u8 v;
+	u8 clk_delay, data_delay;
+	int ret;
+
+	ub960_read_ind(priv, UB960_IND_TARGET_RX_ANA(nport),
+		       UB960_IR_RX_ANA_STROBE_SET_CLK, &v);
+
+	clk_delay = v & UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY ? 0 : 6;
+
+	ub960_read_ind(priv, UB960_IND_TARGET_RX_ANA(nport),
+		       UB960_IR_RX_ANA_STROBE_SET_DATA, &v);
+
+	data_delay = v & UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY ? 0 : 6;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_SFILTER_STS_0, &v);
+	if (ret)
+		return ret;
+
+	clk_delay += v & UB960_IR_RX_ANA_STROBE_SET_CLK_DELAY_MASK;
+
+	ub960_rxport_read(priv, nport, UB960_RR_SFILTER_STS_1, &v);
+	if (ret)
+		return ret;
+
+	data_delay += v & UB960_IR_RX_ANA_STROBE_SET_DATA_DELAY_MASK;
+
+	*strobe_pos = data_delay - clk_delay;
+
+	return 0;
+}
+
+static void ub960_rxport_set_strobe_pos(struct ub960_data *priv,
+					unsigned int nport, s8 strobe_pos)
+{
+	u8 clk_delay, data_delay;
+
+	if (WARN_ON(strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
+		    strobe_pos > UB960_MAX_MANUAL_STROBE_POS))
+		return;
+
+	clk_delay = UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
+	data_delay = UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
+
+	if (strobe_pos < -7)
+		clk_delay = abs(strobe_pos) - 6;
+	else if (strobe_pos > 7)
+		data_delay = strobe_pos - 6;
+	else if (strobe_pos < 0)
+		clk_delay = abs(strobe_pos) | UB960_IR_RX_ANA_STROBE_SET_CLK_NO_EXTRA_DELAY;
+	else if (strobe_pos > 0)
+		data_delay = strobe_pos | UB960_IR_RX_ANA_STROBE_SET_DATA_NO_EXTRA_DELAY;
+
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport),
+			UB960_IR_RX_ANA_STROBE_SET_CLK, clk_delay);
+
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport),
+			UB960_IR_RX_ANA_STROBE_SET_DATA, data_delay);
+}
+
+static void ub960_rxport_set_strobe_range(struct ub960_data *priv,
+					  s8 strobe_min, s8 strobe_max)
+{
+	WARN_ON(strobe_min < UB960_MIN_AEQ_STROBE_POS);
+	WARN_ON(strobe_max > UB960_MAX_AEQ_STROBE_POS);
+
+	strobe_min += 7;
+	strobe_max += 7;
+
+	ub960_write(priv, UB960_XR_SFILTER_CFG,
+		    ((u8)strobe_min << UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT) |
+		    ((u8)strobe_max << UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT));
+}
+
+static int ub960_rxport_get_eq_level(struct ub960_data *priv,
+				     unsigned int nport, u8 *eq_level)
+{
+	int ret;
+	u8 v;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_AEQ_STATUS, &v);
+	if (ret)
+		return ret;
+
+	*eq_level = (v & 0x7) + ((v >> 3) & 0x7);
+
+	return 0;
+}
+
+static void ub960_rxport_set_eq_level(struct ub960_data *priv,
+				      unsigned int nport, u8 eq_level)
+{
+	u8 eq_stage_1_select_value, eq_stage_2_select_value;
+	u8 v;
+
+	if (eq_level <= 7) {
+		eq_stage_1_select_value = eq_level;
+		eq_stage_2_select_value = 0;
+	} else {
+		eq_stage_1_select_value = 7;
+		eq_stage_2_select_value = eq_level - 7;
+	}
+
+	WARN_ON(eq_stage_1_select_value > 7);
+	WARN_ON(eq_stage_2_select_value > 7);
+
+	ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
+
+	v &= ~(UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_MASK |
+	       UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_MASK);
+	v |= eq_stage_1_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE1_VALUE_SHIFT;
+	v |= eq_stage_2_select_value << UB960_RR_AEQ_BYPASS_EQ_STAGE2_VALUE_SHIFT;
+	v |= UB960_RR_AEQ_BYPASS_ENABLE; /* Enable AEQ Bypass */
+
+	ub960_rxport_write(priv, nport, UB960_RR_AEQ_BYPASS, v);
+}
+
+static void ub960_rxport_set_eq_range(struct ub960_data *priv,
+				      unsigned int nport, u8 eq_min, u8 eq_max)
+{
+	ub960_rxport_write(priv, nport, UB960_RR_AEQ_MIN_MAX,
+			   (eq_min << UB960_RR_AEQ_MIN_MAX_AEQ_FLOOR_SHIFT) |
+			   (eq_max << UB960_RR_AEQ_MIN_MAX_AEQ_MAX_SHIFT));
+
+	/* Enable AEQ min setting */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_CTL2,
+				 UB960_RR_AEQ_CTL2_SET_AEQ_FLOOR,
+				 UB960_RR_AEQ_CTL2_SET_AEQ_FLOOR);
+}
+
+static void ub960_rxport_config_eq(struct ub960_data *priv, unsigned int nport)
+{
+	struct ub960_rxport *rxport = priv->rxports[nport];
+
+	/* We also set common settings here. Should be moved elsewhere. */
+
+	if (priv->strobe.manual) {
+		/* Disable AEQ_SFILTER_EN */
+		ub960_update_bits(priv, UB960_XR_AEQ_CTL1,
+				  UB960_XR_AEQ_CTL1_AEQ_SFILTER_EN, 0);
+	} else {
+		/* Enable SFILTER and error control */
+		ub960_write(priv, UB960_XR_AEQ_CTL1,
+			    (0x7 << UB960_XR_AEQ_CTL1_AEQ_ERR_CTL_SHIFT) |
+				    UB960_XR_AEQ_CTL1_AEQ_SFILTER_EN);
+
+		/* Set AEQ strobe range */
+		ub960_rxport_set_strobe_range(priv, priv->strobe.min,
+					      priv->strobe.max);
+	}
+
+	/* The rest are port specific */
+
+	if (priv->strobe.manual)
+		ub960_rxport_set_strobe_pos(priv, nport, rxport->eq.strobe_pos);
+	else
+		ub960_rxport_set_strobe_pos(priv, nport, 0);
+
+	if (rxport->eq.manual_eq) {
+		ub960_rxport_set_eq_level(priv, nport,
+					  rxport->eq.manual.eq_level);
+
+		/* Enable AEQ Bypass */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
+					 UB960_RR_AEQ_BYPASS_ENABLE,
+					 UB960_RR_AEQ_BYPASS_ENABLE);
+	} else {
+		ub960_rxport_set_eq_range(priv, nport,
+					  rxport->eq.aeq.eq_level_min,
+					  rxport->eq.aeq.eq_level_max);
+
+		/* Disable AEQ Bypass */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_AEQ_BYPASS,
+					 UB960_RR_AEQ_BYPASS_ENABLE, 0);
+	}
+}
+
+static int ub960_rxport_link_ok(struct ub960_data *priv, unsigned int nport,
+				bool *ok)
+{
+	u8 rx_port_sts1, rx_port_sts2;
+	unsigned int parity_errors;
+	u8 csi_rx_sts;
+	u8 csi_err_cnt;
+	u8 v1, v2;
+	u8 bcc_sts;
+	int ret;
+	bool errors;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS1,
+				&rx_port_sts1);
+	if (ret)
+		return ret;
+
+	if (!(rx_port_sts1 & UB960_RR_RX_PORT_STS1_LOCK_STS)) {
+		*ok = false;
+		return 0;
+	}
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS2,
+				&rx_port_sts2);
+	if (ret)
+		return ret;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_CSI_RX_STS, &csi_rx_sts);
+	if (ret)
+		return ret;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_CSI_ERR_COUNTER,
+				&csi_err_cnt);
+	if (ret)
+		return ret;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_BCC_STATUS, &bcc_sts);
+	if (ret)
+		return ret;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
+	if (ret)
+		return ret;
+
+	ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
+	if (ret)
+		return ret;
+
+	parity_errors = (v1 << 8) | v2;
+
+	errors = (rx_port_sts1 & 0x2c) || (rx_port_sts2 & 0x20) ||
+		 (bcc_sts & 0x3f) || (csi_rx_sts & 0xf) || csi_err_cnt ||
+		 parity_errors;
+
+	*ok = !errors;
+
+	return 0;
+}
+
+/*
+ * Wait for the RX ports to lock, have no errors and have stable strobe position
+ * and EQ level.
+ */
+static int ub960_rxport_wait_locks(struct ub960_data *priv,
+				   unsigned long port_mask,
+				   unsigned int *lock_mask)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned long timeout;
+	unsigned int link_ok_mask;
+	unsigned int missing;
+	unsigned int loops;
+	u8 nport;
+	int ret;
+
+	if (port_mask == 0)
+		return 0;
+
+	if (port_mask >= BIT(priv->hw_data->num_rxports))
+		return -EINVAL;
+
+	timeout = jiffies + msecs_to_jiffies(1000);
+	loops = 0;
+	link_ok_mask = 0;
+
+	while (time_before(jiffies, timeout)) {
+		missing = 0;
+
+		for_each_set_bit(nport, &port_mask,
+				 priv->hw_data->num_rxports) {
+			struct ub960_rxport *rxport = priv->rxports[nport];
+			bool ok;
+
+			if (!rxport)
+				continue;
+
+			ret = ub960_rxport_link_ok(priv, nport, &ok);
+			if (ret)
+				return ret;
+
+			if (!ok || !(link_ok_mask & BIT(nport)))
+				missing++;
+
+			if (ok)
+				link_ok_mask |= BIT(nport);
+			else
+				link_ok_mask &= ~BIT(nport);
+		}
+
+		loops++;
+
+		if (missing == 0)
+			break;
+
+		msleep(50);
+	}
+
+	if (lock_mask)
+		*lock_mask = link_ok_mask;
+
+	dev_dbg(dev, "Wait locks done in %u loops\n", loops);
+	for_each_set_bit(nport, &port_mask, priv->hw_data->num_rxports) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+		s8 strobe_pos, eq_level;
+		u8 v1, v2;
+
+		if (!rxport)
+			continue;
+
+		if (!(link_ok_mask & BIT(nport))) {
+			dev_dbg(dev, "\trx%u: not locked\n", nport);
+			continue;
+		}
+
+		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
+
+		ret = ub960_rxport_get_strobe_pos(priv, nport, &strobe_pos);
+		if (ret)
+			return ret;
+
+		ret = ub960_rxport_get_eq_level(priv, nport, &eq_level);
+		if (ret)
+			return ret;
+
+		dev_dbg(dev, "\trx%u: locked, SP: %d, EQ: %u, freq %u Hz\n",
+			nport, strobe_pos, eq_level,
+			v1 * 1000000 + v2 * 1000000 / 256);
+	}
+
+	return 0;
+}
+
+static int ub960_init_atr(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	struct i2c_adapter *parent_adap = priv->client->adapter;
+
+	priv->atr = i2c_atr_new(parent_adap, dev, &ub960_atr_ops,
+				priv->hw_data->num_rxports);
+	if (IS_ERR(priv->atr))
+		return PTR_ERR(priv->atr);
+
+	i2c_atr_set_driver_data(priv->atr, priv);
+
+	return 0;
+}
+
+static void ub960_uninit_atr(struct ub960_data *priv)
+{
+	i2c_atr_delete(priv->atr);
+	priv->atr = NULL;
+}
+
+static unsigned long ub960_calc_bc_clk_rate_ub960(struct ub960_data *priv,
+						  struct ub960_rxport *rxport)
+{
+	unsigned int mult;
+	unsigned int div;
+
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+	case RXPORT_MODE_RAW12_HF:
+	case RXPORT_MODE_RAW12_LF:
+		mult = 1;
+		div = 10;
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+		mult = 2;
+		div = 1;
+		break;
+
+	case RXPORT_MODE_CSI2_ASYNC:
+		mult = 2;
+		div = 5;
+		break;
+
+	default:
+		WARN_ON(true);
+		return 0;
+	}
+
+	return clk_get_rate(priv->refclk) * mult / div;
+}
+
+static unsigned long ub960_calc_bc_clk_rate_ub9702(struct ub960_data *priv,
+						   struct ub960_rxport *rxport)
+{
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+	case RXPORT_MODE_RAW12_HF:
+	case RXPORT_MODE_RAW12_LF:
+		return 2359400;
+
+	case RXPORT_MODE_CSI2_SYNC:
+		return 47187500;
+
+	case RXPORT_MODE_CSI2_ASYNC:
+		return 9437500;
+
+	default:
+		WARN_ON(true);
+		return 0;
+	}
+}
+
+static int ub960_rxport_add_serializer(struct ub960_data *priv, u8 nport)
+{
+	struct ub960_rxport *rxport = priv->rxports[nport];
+	struct device *dev = &priv->client->dev;
+	struct ds90ub9xx_platform_data *ser_pdata = &rxport->ser_platform_data;
+	struct i2c_board_info ser_info = {
+		.of_node = to_of_node(rxport->remote_fwnode),
+		.fwnode = rxport->remote_fwnode,
+		.platform_data = ser_pdata,
+	};
+
+	ser_pdata->port = nport;
+	ser_pdata->atr = priv->atr;
+	if (priv->hw_data->is_ub9702)
+		ser_pdata->bc_rate = ub960_calc_bc_clk_rate_ub9702(priv, rxport);
+	else
+		ser_pdata->bc_rate = ub960_calc_bc_clk_rate_ub960(priv, rxport);
+
+	/*
+	 * Adding the serializer under rxport->adap would be cleaner, but it
+	 * would need tweaks to bypass the alias table. Adding to the
+	 * upstream adapter is way simpler.
+	 */
+	ser_info.addr = rxport->ser_alias;
+	rxport->ser_client =
+		i2c_new_client_device(priv->client->adapter, &ser_info);
+	if (!rxport->ser_client) {
+		dev_err(dev, "rx%u: cannot add %s i2c device", nport,
+			ser_info.type);
+		return -EIO;
+	}
+
+	dev_dbg(dev, "rx%u: remote serializer at alias 0x%02x (%u-%04x)\n",
+		nport, rxport->ser_client->addr,
+		rxport->ser_client->adapter->nr, rxport->ser_client->addr);
+
+	return 0;
+}
+
+static void ub960_rxport_remove_serializer(struct ub960_data *priv, u8 nport)
+{
+	struct ub960_rxport *rxport = priv->rxports[nport];
+
+	i2c_unregister_device(rxport->ser_client);
+	rxport->ser_client = NULL;
+}
+
+/* Add serializer i2c devices for all initialized ports */
+static int ub960_rxport_add_serializers(struct ub960_data *priv)
+{
+	unsigned int nport;
+	int ret;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport)
+			continue;
+
+		ret = ub960_rxport_add_serializer(priv, nport);
+		if (ret)
+			goto err_remove_sers;
+	}
+
+	return 0;
+
+err_remove_sers:
+	for (; nport > 0; --nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport - 1];
+
+		if (!rxport)
+			continue;
+
+		rxport = priv->rxports[nport - 1];
+		if (!rxport)
+			continue;
+
+		ub960_rxport_remove_serializer(priv, nport - 1);
+	}
+
+	return ret;
+}
+
+static void ub960_rxport_remove_serializers(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport)
+			continue;
+
+		ub960_rxport_remove_serializer(priv, nport);
+	}
+}
+
+static void ub960_init_tx_port(struct ub960_data *priv,
+			       struct ub960_txport *txport)
+{
+	unsigned int nport = txport->nport;
+	u8 csi_ctl = 0;
+
+	/*
+	 * From the datasheet: "initial CSI Skew-Calibration
+	 * sequence [...] should be set when operating at 1.6 Gbps"
+	 */
+	if (priv->tx_data_rate == 1600000000)
+		csi_ctl |= UB960_TR_CSI_CTL_CSI_CAL_EN;
+
+	csi_ctl |= (4 - txport->num_data_lanes) << 4;
+
+	ub960_csiport_write(priv, nport, UB960_TR_CSI_CTL, csi_ctl);
+}
+
+static int ub960_init_tx_ports(struct ub960_data *priv)
+{
+	unsigned int nport;
+	u8 speed_select;
+	u8 pll_div;
+
+	/* TX ports */
+
+	switch (priv->tx_data_rate) {
+	case 1600000000:
+	default:
+		speed_select = 0;
+		pll_div = 0x10;
+		break;
+	case 1200000000:
+		speed_select = 1;
+		break;
+	case 800000000:
+		speed_select = 2;
+		pll_div = 0x10;
+		break;
+	case 400000000:
+		speed_select = 3;
+		pll_div = 0x10;
+		break;
+	}
+
+	ub960_write(priv, UB960_SR_CSI_PLL_CTL, speed_select);
+
+	if (priv->hw_data->is_ub9702) {
+		ub960_write(priv, UB960_SR_CSI_PLL_DIV, pll_div);
+
+		switch (priv->tx_data_rate) {
+		case 1600000000:
+		default:
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x92, 0x80);
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x4B, 0x2A);
+			break;
+		case 800000000:
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x92, 0x90);
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x4F, 0x2A);
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x4B, 0x2A);
+			break;
+		case 400000000:
+			ub960_write_ind(priv, UB960_IND_TARGET_CSI_ANA, 0x92, 0xA0);
+			break;
+		}
+	}
+
+	for (nport = 0; nport < priv->hw_data->num_txports; nport++) {
+		struct ub960_txport *txport = priv->txports[nport];
+
+		if (!txport)
+			continue;
+
+		ub960_init_tx_port(priv, txport);
+	}
+
+	return 0;
+}
+
+static void ub960_init_rx_port_ub960(struct ub960_data *priv,
+				     struct ub960_rxport *rxport)
+{
+	unsigned int nport = rxport->nport;
+	u32 bc_freq_val;
+
+	/*
+	 * Back channel frequency select.
+	 * Override FREQ_SELECT from the strap.
+	 * 0 - 2.5 Mbps (DS90UB913A-Q1 / DS90UB933-Q1)
+	 * 2 - 10 Mbps
+	 * 6 - 50 Mbps (DS90UB953-Q1)
+	 *
+	 * Note that changing this setting will result in some errors on the back
+	 * channel for a short period of time.
+	 */
+
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+	case RXPORT_MODE_RAW12_HF:
+	case RXPORT_MODE_RAW12_LF:
+		bc_freq_val = 0;
+		break;
+
+	case RXPORT_MODE_CSI2_ASYNC:
+		bc_freq_val = 2;
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+		bc_freq_val = 6;
+		break;
+
+	default:
+		WARN_ON(true);
+		return;
+	}
+
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG, 0x7,
+				 bc_freq_val);
+
+	switch (rxport->rx_mode) {
+	default:
+		WARN_ON(true);
+		fallthrough;
+
+	case RXPORT_MODE_RAW10:
+		/* FPD3_MODE = RAW10 Mode (DS90UB913A-Q1 / DS90UB933-Q1 compatible) */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG, 0x3,
+					 0x3);
+
+		/*
+		 * RAW10_8BIT_CTL = 0b11 : 8-bit processing using lower 8 bits
+		 * 0b10 : 8-bit processing using upper 8 bits
+		 */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2,
+					 0x3 << 6, 0x2 << 6);
+
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+	case RXPORT_MODE_CSI2_ASYNC:
+		/* CSI-2 Mode (DS90UB953-Q1 compatible) */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG, 0x3,
+					 0x0);
+
+		break;
+	}
+
+	/* LV_POLARITY & FV_POLARITY */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2, 0x3,
+				 rxport->lv_fv_pol);
+
+	/* Enable all interrupt sources from this port */
+	ub960_rxport_write(priv, nport, UB960_RR_PORT_ICR_HI, 0x07);
+	ub960_rxport_write(priv, nport, UB960_RR_PORT_ICR_LO, 0x7f);
+
+	/* Enable I2C_PASS_THROUGH */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH);
+
+	/* Enable I2C communication to the serializer via the alias addr */
+	ub960_rxport_write(priv, nport, UB960_RR_SER_ALIAS_ID,
+			   rxport->ser_alias << 1);
+
+	/* Configure EQ related settings */
+	ub960_rxport_config_eq(priv, nport);
+
+	/* Enable RX port */
+	ub960_update_bits(priv, UB960_SR_RX_PORT_CTL, BIT(nport), BIT(nport));
+}
+
+static void ub960_init_rx_port_ub9702_fpd3(struct ub960_data *priv,
+					   struct ub960_rxport *rxport)
+{
+	unsigned int nport = rxport->nport;
+	u8 bc_freq_val;
+	u8 fpd_func_mode;
+
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+		bc_freq_val = 0;
+		fpd_func_mode = 5;
+		break;
+
+	case RXPORT_MODE_RAW12_HF:
+		bc_freq_val = 0;
+		fpd_func_mode = 4;
+		break;
+
+	case RXPORT_MODE_RAW12_LF:
+		bc_freq_val = 0;
+		fpd_func_mode = 6;
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+		bc_freq_val = 6;
+		fpd_func_mode = 2;
+		break;
+
+	case RXPORT_MODE_CSI2_ASYNC:
+		bc_freq_val = 2;
+		fpd_func_mode = 2;
+		break;
+
+	default:
+		WARN_ON(true);
+		return;
+	}
+
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG, 0x7,
+				 bc_freq_val);
+	ub960_rxport_write(priv, nport, UB960_RR_CHANNEL_MODE, fpd_func_mode);
+
+	/* set serdes_eq_mode = 1 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0xA8, 0x80);
+
+	/* enable serdes driver */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x0D, 0x7F);
+
+	/* set serdes_eq_offset=4 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x2B, 0x04);
+
+	/* init default serdes_eq_max in 0xA9 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0xA9, 0x23);
+
+	/* init serdes_eq_min in 0xAA */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0xAA, 0);
+
+	/* serdes_driver_ctl2 control: DS90UB953-Q1/DS90UB933-Q1/DS90UB913A-Q1 */
+	ub960_ind_update_bits(priv, UB960_IND_TARGET_RX_ANA(nport), 0x1b,
+			      BIT(3), BIT(3));
+
+	/* RX port to half-rate */
+	ub960_update_bits(priv, UB960_SR_FPD_RATE_CFG, 0x3 << (nport * 2),
+			  1 << (nport * 2));
+}
+
+static void ub960_init_rx_port_ub9702_fpd4_aeq(struct ub960_data *priv,
+					       struct ub960_rxport *rxport)
+{
+	unsigned int nport = rxport->nport;
+	bool first_time_power_up = true;
+
+	if (first_time_power_up) {
+		u8 v;
+
+		/* AEQ init */
+		ub960_read_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x2C, &v);
+
+		ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x27, v);
+		ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x28, v + 1);
+
+		ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x2B, 0x00);
+	}
+
+	/* enable serdes_eq_ctl2 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x9E, 0x00);
+
+	/* enable serdes_eq_ctl1 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x90, 0x40);
+
+	/* enable serdes_eq_en */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x2E, 0x40);
+
+	/* disable serdes_eq_override */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0xF0, 0x00);
+
+	/* disable serdes_gain_override */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x71, 0x00);
+}
+
+static void ub960_init_rx_port_ub9702_fpd4(struct ub960_data *priv,
+					   struct ub960_rxport *rxport)
+{
+	unsigned int nport = rxport->nport;
+	u8 bc_freq_val;
+
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+		bc_freq_val = 0;
+		break;
+
+	case RXPORT_MODE_RAW12_HF:
+		bc_freq_val = 0;
+		break;
+
+	case RXPORT_MODE_RAW12_LF:
+		bc_freq_val = 0;
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+		bc_freq_val = 6;
+		break;
+
+	case RXPORT_MODE_CSI2_ASYNC:
+		bc_freq_val = 2;
+		break;
+
+	default:
+		WARN_ON(true);
+		return;
+	}
+
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG, 0x7,
+				 bc_freq_val);
+
+	/* FPD4 Sync Mode */
+	ub960_rxport_write(priv, nport, UB960_RR_CHANNEL_MODE, 0);
+
+	/* add serdes_eq_offset of 4 */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x2B, 0x04);
+
+	/* FPD4 serdes_start_eq in 0x27: assign default */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x27, 0x0);
+	/* FPD4 serdes_end_eq in 0x28: assign default */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x28, 0x23);
+
+	/* set serdes_driver_mode into FPD IV mode */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x04, 0x00);
+	/* set FPD PBC drv into FPD IV mode */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x1B, 0x00);
+
+	/* set serdes_system_init to 0x2f */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x21, 0x2f);
+	/* set serdes_system_rst in reset mode */
+	ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x25, 0xC1);
+
+	/* RX port to 7.55G mode */
+	ub960_update_bits(priv, UB960_SR_FPD_RATE_CFG, 0x3 << (nport * 2),
+			  0 << (nport * 2));
+
+	ub960_init_rx_port_ub9702_fpd4_aeq(priv, rxport);
+}
+
+static void ub960_init_rx_port_ub9702(struct ub960_data *priv,
+				      struct ub960_rxport *rxport)
+{
+	unsigned int nport = rxport->nport;
+
+	if (rxport->cdr_mode == RXPORT_CDR_FPD3)
+		ub960_init_rx_port_ub9702_fpd3(priv, rxport);
+	else /* RXPORT_CDR_FPD4 */
+		ub960_init_rx_port_ub9702_fpd4(priv, rxport);
+
+	switch (rxport->rx_mode) {
+	default:
+		WARN_ON(true);
+		fallthrough;
+
+	case RXPORT_MODE_RAW10:
+		/*
+		 * RAW10_8BIT_CTL = 0b11 : 8-bit processing using lower 8 bits
+		 * 0b10 : 8-bit processing using upper 8 bits
+		 */
+		ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2,
+					 0x3 << 6, 0x2 << 6);
+
+		break;
+
+	case RXPORT_MODE_CSI2_SYNC:
+	case RXPORT_MODE_CSI2_ASYNC:
+
+		break;
+	}
+
+	/* LV_POLARITY & FV_POLARITY */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_PORT_CONFIG2, 0x3, 0x1);
+
+	/* Enable all interrupt sources from this port */
+	ub960_rxport_write(priv, nport, UB960_RR_PORT_ICR_HI, 0x07);
+	ub960_rxport_write(priv, nport, UB960_RR_PORT_ICR_LO, 0x7f);
+
+	/* Enable I2C_PASS_THROUGH */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH);
+
+	/* Enable I2C communication to the serializer via the alias addr */
+	ub960_rxport_write(priv, nport, UB960_RR_SER_ALIAS_ID,
+			   rxport->ser_alias << 1);
+
+	/* Enable RX port */
+	ub960_update_bits(priv, UB960_SR_RX_PORT_CTL, BIT(nport), BIT(nport));
+
+	if (rxport->cdr_mode == RXPORT_CDR_FPD4) {
+		/* unreset 960 AEQ */
+		ub960_write_ind(priv, UB960_IND_TARGET_RX_ANA(nport), 0x25, 0x41);
+	}
+}
+
+static int ub960_init_rx_ports(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; nport++) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport)
+			continue;
+
+		if (priv->hw_data->is_ub9702)
+			ub960_init_rx_port_ub9702(priv, rxport);
+		else
+			ub960_init_rx_port_ub960(priv, rxport);
+	}
+
+	return 0;
+}
+
+static void ub960_rxport_handle_events(struct ub960_data *priv, u8 nport)
+{
+	struct device *dev = &priv->client->dev;
+	u8 rx_port_sts1;
+	u8 rx_port_sts2;
+	u8 csi_rx_sts;
+	u8 bcc_sts;
+	int ret = 0;
+
+	/* Read interrupts (also clears most of them) */
+	if (!ret)
+		ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS1,
+					&rx_port_sts1);
+	if (!ret)
+		ret = ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS2,
+					&rx_port_sts2);
+	if (!ret)
+		ret = ub960_rxport_read(priv, nport, UB960_RR_CSI_RX_STS,
+					&csi_rx_sts);
+	if (!ret)
+		ret = ub960_rxport_read(priv, nport, UB960_RR_BCC_STATUS,
+					&bcc_sts);
+
+	if (ret)
+		return;
+
+	if (rx_port_sts1 & UB960_RR_RX_PORT_STS1_PARITY_ERROR) {
+		u8 v1, v2;
+
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
+		dev_err(dev, "rx%u parity errors: %u\n", nport, (v1 << 8) | v2);
+	}
+
+	if (rx_port_sts1 & UB960_RR_RX_PORT_STS1_BCC_CRC_ERROR)
+		dev_err(dev, "rx%u BCC CRC error\n", nport);
+
+	if (rx_port_sts1 & UB960_RR_RX_PORT_STS1_BCC_SEQ_ERROR)
+		dev_err(dev, "rx%u BCC SEQ error\n", nport);
+
+	if (rx_port_sts2 & UB960_RR_RX_PORT_STS2_LINE_LEN_UNSTABLE)
+		dev_err(dev, "rx%u line length unstable\n", nport);
+
+	if (rx_port_sts2 & UB960_RR_RX_PORT_STS2_FPD3_ENCODE_ERROR)
+		dev_err(dev, "rx%u FPD3 encode error\n", nport);
+
+	if (rx_port_sts2 & UB960_RR_RX_PORT_STS2_BUFFER_ERROR)
+		dev_err(dev, "rx%u buffer error\n", nport);
+
+	if (csi_rx_sts)
+		dev_err(dev, "rx%u CSI error: %#02x\n", nport, csi_rx_sts);
+
+	if (csi_rx_sts & UB960_RR_CSI_RX_STS_ECC1_ERR)
+		dev_err(dev, "rx%u CSI ECC1 error\n", nport);
+
+	if (csi_rx_sts & UB960_RR_CSI_RX_STS_ECC2_ERR)
+		dev_err(dev, "rx%u CSI ECC2 error\n", nport);
+
+	if (csi_rx_sts & UB960_RR_CSI_RX_STS_CKSUM_ERR)
+		dev_err(dev, "rx%u CSI checksum error\n", nport);
+
+	if (csi_rx_sts & UB960_RR_CSI_RX_STS_LENGTH_ERR)
+		dev_err(dev, "rx%u CSI length error\n", nport);
+
+	if (bcc_sts)
+		dev_err(dev, "rx%u BCC error: %#02x\n", nport, bcc_sts);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_RESP_ERR)
+		dev_err(dev, "rx%u BCC response error", nport);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_SLAVE_TO)
+		dev_err(dev, "rx%u BCC slave timeout", nport);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_SLAVE_ERR)
+		dev_err(dev, "rx%u BCC slave error", nport);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_MASTER_TO)
+		dev_err(dev, "rx%u BCC master timeout", nport);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_MASTER_ERR)
+		dev_err(dev, "rx%u BCC master error", nport);
+
+	if (bcc_sts & UB960_RR_BCC_STATUS_SEQ_ERROR)
+		dev_err(dev, "rx%u BCC sequence error", nport);
+
+	if (rx_port_sts2 & UB960_RR_RX_PORT_STS2_LINE_LEN_CHG) {
+		u8 v1, v2;
+
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_LEN_1, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_LEN_0, &v2);
+		dev_dbg(dev, "rx%u line len changed: %u\n", nport,
+			(v1 << 8) | v2);
+	}
+
+	if (rx_port_sts2 & UB960_RR_RX_PORT_STS2_LINE_CNT_CHG) {
+		u8 v1, v2;
+
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_COUNT_HI, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_COUNT_LO, &v2);
+		dev_dbg(dev, "rx%u line count changed: %u\n", nport,
+			(v1 << 8) | v2);
+	}
+
+	if (rx_port_sts1 & UB960_RR_RX_PORT_STS1_LOCK_STS_CHG) {
+		dev_dbg(dev, "rx%u: %s, %s, %s, %s\n", nport,
+			(rx_port_sts1 & UB960_RR_RX_PORT_STS1_LOCK_STS) ?
+				"locked" :
+				"unlocked",
+			(rx_port_sts1 & UB960_RR_RX_PORT_STS1_PORT_PASS) ?
+				"passed" :
+				"not passed",
+			(rx_port_sts2 & UB960_RR_RX_PORT_STS2_CABLE_FAULT) ?
+				"no clock" :
+				"clock ok",
+			(rx_port_sts2 & UB960_RR_RX_PORT_STS2_FREQ_STABLE) ?
+				"stable freq" :
+				"unstable freq");
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * V4L2
+ */
+
+static void ub960_get_vc_maps(struct ub960_data *priv,
+			      struct v4l2_subdev_state *state, u8 *vc)
+{
+	const struct v4l2_subdev_krouting *routing = &state->routing;
+	u8 cur_vc[UB960_MAX_TX_NPORTS] = { 0 };
+	u8 handled_mask = 0;
+	unsigned int i;
+
+	for (i = 0; i < routing->num_routes; ++i) {
+		struct v4l2_subdev_route *route = &routing->routes[i];
+		unsigned int rx, tx;
+
+		rx = ub960_pad_to_port(priv, route->sink_pad);
+
+		if (BIT(rx) & handled_mask)
+			continue;
+
+		tx = ub960_pad_to_port(priv, route->source_pad);
+
+		vc[rx] = cur_vc[tx]++;
+		handled_mask |= BIT(rx);
+	}
+}
+
+static int ub960_enable_tx_port(struct ub960_data *priv, unsigned int nport)
+{
+	struct device *dev = &priv->client->dev;
+
+	dev_dbg(dev, "enable TX port %u\n", nport);
+
+	ub960_csiport_update_bits(priv, nport, UB960_TR_CSI_CTL,
+				  UB960_TR_CSI_CTL_CSI_ENABLE,
+				  UB960_TR_CSI_CTL_CSI_ENABLE);
+
+	return 0;
+}
+
+static void ub960_disable_tx_port(struct ub960_data *priv, unsigned int nport)
+{
+	struct device *dev = &priv->client->dev;
+
+	dev_dbg(dev, "disable TX port %u\n", nport);
+
+	ub960_csiport_update_bits(priv, nport, UB960_TR_CSI_CTL,
+				  UB960_TR_CSI_CTL_CSI_ENABLE, 0);
+}
+
+static int ub960_enable_rx_port(struct ub960_data *priv, unsigned int nport)
+{
+	struct device *dev = &priv->client->dev;
+
+	dev_dbg(dev, "enable RX port %u\n", nport);
+
+	/* Enable forwarding */
+	ub960_update_bits(priv, UB960_SR_FWD_CTL1, BIT(4 + nport), 0);
+
+	return 0;
+}
+
+static void ub960_disable_rx_port(struct ub960_data *priv, unsigned int nport)
+{
+	struct device *dev = &priv->client->dev;
+
+	dev_dbg(dev, "disable RX port %u\n", nport);
+
+	/* Disable forwarding */
+	ub960_update_bits(priv, UB960_SR_FWD_CTL1, BIT(4 + nport),
+			  BIT(4 + nport));
+}
+
+static int ub960_configure_ports_for_streaming(struct ub960_data *priv,
+					       struct v4l2_subdev_state *state)
+{
+	const struct v4l2_subdev_krouting *routing = &state->routing;
+	u8 fwd_ctl;
+	struct {
+		u32 num_streams;
+		u8 pixel_dt;
+		u8 meta_dt;
+		u32 meta_lines;
+		u32 tx_port;
+	} rx_data[UB960_MAX_RX_NPORTS] = { 0 };
+	u8 vc_map[UB960_MAX_RX_NPORTS] = { 0 };
+
+	ub960_get_vc_maps(priv, state, vc_map);
+
+	for (unsigned int i = 0; i < routing->num_routes; ++i) {
+		struct v4l2_subdev_route *route = &routing->routes[i];
+		struct ub960_rxport *rxport;
+		struct ub960_txport *txport;
+		struct v4l2_mbus_framefmt *fmt;
+		const struct ub960_format_info *ub960_fmt;
+		unsigned int nport;
+
+		nport = ub960_pad_to_port(priv, route->sink_pad);
+
+		rxport = priv->rxports[nport];
+		if (!rxport)
+			return -EINVAL;
+
+		txport = priv->txports[ub960_pad_to_port(priv, route->source_pad)];
+		if (!txport)
+			return -EINVAL;
+
+		rx_data[nport].tx_port = ub960_pad_to_port(priv, route->source_pad);
+
+		rx_data[nport].num_streams++;
+
+		/* For the rest, we are only interested in parallel busses */
+		if (rxport->rx_mode == RXPORT_MODE_CSI2_SYNC ||
+		    rxport->rx_mode == RXPORT_MODE_CSI2_ASYNC)
+			continue;
+
+		if (rx_data[nport].num_streams > 2)
+			return -EPIPE;
+
+		fmt = v4l2_subdev_state_get_stream_format(state,
+							  route->sink_pad,
+							  route->sink_stream);
+		if (!fmt)
+			return -EPIPE;
+
+		ub960_fmt = ub960_find_format(fmt->code);
+		if (!ub960_fmt)
+			return -EPIPE;
+
+		if (ub960_fmt->meta) {
+			if (fmt->height > 3) {
+				dev_err(&priv->client->dev,
+					"rx%u: unsupported metadata height %u\n",
+					nport, fmt->height);
+				return -EPIPE;
+			}
+
+			rx_data[nport].meta_dt = ub960_fmt->datatype;
+			rx_data[nport].meta_lines = fmt->height;
+		} else {
+			rx_data[nport].pixel_dt = ub960_fmt->datatype;
+		}
+	}
+
+	/* Configure RX ports */
+
+	fwd_ctl = 0;
+
+	for (unsigned int nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+		u8 vc = vc_map[nport];
+
+		if (rx_data[nport].num_streams == 0)
+			continue;
+
+		switch (rxport->rx_mode) {
+		default:
+			WARN_ON(true);
+			fallthrough;
+
+		case RXPORT_MODE_RAW10:
+			ub960_rxport_write(priv, nport, UB960_RR_RAW10_ID,
+					   rx_data[nport].pixel_dt | (vc << 6));
+
+			ub960_rxport_write(priv, rxport->nport,
+					   UB960_RR_RAW_EMBED_DTYPE,
+					   (rx_data[nport].meta_lines << 6) |
+						   rx_data[nport].meta_dt);
+
+			break;
+
+		case RXPORT_MODE_CSI2_SYNC:
+		case RXPORT_MODE_CSI2_ASYNC:
+			if (!priv->hw_data->is_ub9702) {
+				/* Map all VCs from this port to the same VC */
+				ub960_rxport_write(priv, nport, UB960_RR_CSI_VC_MAP,
+						   (vc << 6) | (vc << 4) |
+							   (vc << 2) | (vc << 0));
+			} else {
+				unsigned int i;
+
+				/* Map all VCs from this port to VC(nport) */
+				for (i = 0; i < 8; ++i)
+					ub960_rxport_write(priv, nport,
+							   UB960_RR_VC_ID_MAP(i),
+							   nport);
+			}
+
+			break;
+		}
+
+		/* Forwarding */
+
+		fwd_ctl |= BIT(4 + nport); /* forward disable */
+
+		if (rx_data[nport].tx_port == 1)
+			fwd_ctl |= BIT(nport); /* forward to TX1 */
+		else
+			fwd_ctl &= ~BIT(nport); /* forward to TX0 */
+	}
+
+	ub960_write(priv, UB960_SR_FWD_CTL1, fwd_ctl);
+
+	return 0;
+}
+
+static void ub960_update_streaming_status(struct ub960_data *priv)
+{
+	unsigned int i;
+	bool streaming = false;
+
+	for (i = 0; i < UB960_MAX_NPORTS; ++i) {
+		if (priv->stream_enable_mask[i]) {
+			streaming = true;
+			break;
+		}
+	}
+
+	priv->streaming = streaming;
+}
+
+static int ub960_enable_streams(struct v4l2_subdev *sd,
+				struct v4l2_subdev_state *state, u32 source_pad,
+				u64 source_streams_mask)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	struct device *dev = &priv->client->dev;
+	const struct v4l2_subdev_krouting *routing;
+	unsigned int source_stream;
+	int ret;
+	u64 sink_streams[UB960_MAX_RX_NPORTS] = { 0 };
+	unsigned int nport;
+	unsigned int failed_port;
+
+	dev_dbg(dev, "Enable streams %u:%#llx\n", source_pad,
+		source_streams_mask);
+
+	if (priv->stream_enable_mask[source_pad] & source_streams_mask) {
+		dev_err(dev,
+			"cannot enable already enabled streams on pad %u mask %#llx\n",
+			source_pad, source_streams_mask);
+		return -EBUSY;
+	}
+
+	routing = &state->routing;
+
+	if (!priv->streaming) {
+		dev_dbg(dev, "Prepare for streaming\n");
+		ret = ub960_configure_ports_for_streaming(priv, state);
+		if (ret)
+			return ret;
+	}
+
+	/* Enable TX port if not yet enabled */
+	if (!priv->stream_enable_mask[source_pad]) {
+		ret = ub960_enable_tx_port(priv,
+					   ub960_pad_to_port(priv, source_pad));
+		if (ret)
+			return ret;
+	}
+
+	priv->stream_enable_mask[source_pad] |= source_streams_mask;
+
+	/* Collect sink streams per pad which we need to enable */
+	for (source_stream = 0; source_stream < sizeof(source_streams_mask) * 8;
+	     ++source_stream) {
+		struct v4l2_subdev_route *route;
+
+		if (!(source_streams_mask & BIT_ULL(source_stream)))
+			continue;
+
+		for_each_active_route(routing, route) {
+			if (!(route->source_pad == source_pad) ||
+			    !(route->source_stream == source_stream))
+				continue;
+
+			nport = ub960_pad_to_port(priv, route->sink_pad);
+
+			sink_streams[nport] |= BIT_ULL(route->sink_stream);
+		}
+	}
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		if (!sink_streams[nport])
+			continue;
+
+		/* Enable the RX port if not yet enabled */
+		if (!priv->stream_enable_mask[nport]) {
+			ret = ub960_enable_rx_port(priv, nport);
+			if (ret) {
+				failed_port = nport;
+				goto err;
+			}
+		}
+
+		priv->stream_enable_mask[nport] |= sink_streams[nport];
+
+		dev_dbg(dev, "Enable RX port %u streams %#llx\n", nport,
+			sink_streams[nport]);
+
+		ret = v4l2_subdev_enable_streams(
+			priv->rxports[nport]->source_sd,
+			priv->rxports[nport]->source_sd_pad,
+			sink_streams[nport]);
+		if (ret) {
+			priv->stream_enable_mask[nport] &= ~sink_streams[nport];
+
+			if (!priv->stream_enable_mask[nport])
+				ub960_disable_rx_port(priv, nport);
+
+			failed_port = nport;
+			goto err;
+		}
+	}
+
+	priv->streaming = true;
+
+	return 0;
+
+err:
+	for (nport = 0; nport < failed_port; ++nport) {
+		if (!sink_streams[nport])
+			continue;
+
+		dev_dbg(dev, "Disable RX port %u streams %#llx\n", nport,
+			sink_streams[nport]);
+
+		ret = v4l2_subdev_disable_streams(
+			priv->rxports[nport]->source_sd,
+			priv->rxports[nport]->source_sd_pad,
+			sink_streams[nport]);
+		WARN_ON(ret);
+
+		priv->stream_enable_mask[nport] &= ~sink_streams[nport];
+
+		/* Disable RX port if no active streams */
+		if (!priv->stream_enable_mask[nport])
+			ub960_disable_rx_port(priv, nport);
+	}
+
+	priv->stream_enable_mask[source_pad] &= ~source_streams_mask;
+
+	if (!priv->stream_enable_mask[source_pad])
+		ub960_disable_tx_port(priv,
+				      ub960_pad_to_port(priv, source_pad));
+
+	ub960_update_streaming_status(priv);
+
+	return ret;
+}
+
+static int ub960_disable_streams(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_state *state,
+				 u32 source_pad, u64 source_streams_mask)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	struct device *dev = &priv->client->dev;
+	const struct v4l2_subdev_krouting *routing;
+	int ret;
+	unsigned int source_stream;
+	u64 sink_streams[UB960_MAX_RX_NPORTS] = { 0 };
+	unsigned int nport;
+
+	dev_dbg(dev, "Disable streams %u:%#llx\n", source_pad,
+		source_streams_mask);
+
+	if ((priv->stream_enable_mask[source_pad] & source_streams_mask) != source_streams_mask) {
+		dev_err(dev,
+			"cannot disable already disabled streams on pad %u mask %#llx\n",
+			source_pad, source_streams_mask);
+		return -EBUSY;
+	}
+
+	routing = &state->routing;
+
+	/* Collect sink streams per pad which we need to disable */
+	for (source_stream = 0; source_stream < sizeof(source_streams_mask) * 8;
+	     ++source_stream) {
+		struct v4l2_subdev_route *route;
+
+		if (!(source_streams_mask & BIT_ULL(source_stream)))
+			continue;
+
+		for_each_active_route(routing, route) {
+			if (!(route->source_pad == source_pad) ||
+			    !(route->source_stream == source_stream))
+				continue;
+
+			nport = ub960_pad_to_port(priv, route->sink_pad);
+
+			sink_streams[nport] |= BIT_ULL(route->sink_stream);
+		}
+	}
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		if (!sink_streams[nport])
+			continue;
+
+		dev_dbg(dev, "Disable RX port %u streams %#llx\n", nport,
+			sink_streams[nport]);
+
+		ret = v4l2_subdev_disable_streams(
+			priv->rxports[nport]->source_sd,
+			priv->rxports[nport]->source_sd_pad,
+			sink_streams[nport]);
+		WARN_ON(ret);
+
+		priv->stream_enable_mask[nport] &= ~sink_streams[nport];
+
+		/* Disable RX port if no active streams */
+		if (!priv->stream_enable_mask[nport])
+			ub960_disable_rx_port(priv, nport);
+	}
+
+	/* Disable TX port if no active streams */
+
+	priv->stream_enable_mask[source_pad] &= ~source_streams_mask;
+
+	if (!priv->stream_enable_mask[source_pad])
+		ub960_disable_tx_port(priv,
+				      ub960_pad_to_port(priv, source_pad));
+
+	ub960_update_streaming_status(priv);
+
+	return 0;
+}
+
+static int ub960_s_stream(struct v4l2_subdev *sd, int enable)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	const struct v4l2_subdev_krouting *routing;
+	struct v4l2_subdev_state *state;
+	struct v4l2_subdev_route *route;
+	u64 pad_stream_masks[UB960_MAX_TX_NPORTS] = { 0 };
+	unsigned int nport;
+	int ret = 0;
+
+	state = v4l2_subdev_lock_and_get_active_state(sd);
+
+	routing = &state->routing;
+
+	for_each_active_route(routing, route)
+		pad_stream_masks[ub960_pad_to_port(priv, route->source_pad)] |=
+			BIT_ULL(route->source_stream);
+
+	if (enable) {
+		for (nport = 0; nport < UB960_MAX_TX_NPORTS; ++nport) {
+			if (pad_stream_masks[nport] == 0)
+				continue;
+
+			ret = ub960_enable_streams(
+				sd, state, priv->hw_data->num_rxports + nport,
+				pad_stream_masks[nport]);
+
+			if (ret) {
+				for (; nport > 0; --nport) {
+					if (pad_stream_masks[nport - 1] == 0)
+						continue;
+
+					ub960_disable_streams(
+						sd, state,
+						priv->hw_data->num_rxports +
+							nport - 1,
+						pad_stream_masks[nport - 1]);
+				}
+
+				break;
+			}
+		}
+	} else {
+		for (nport = 0; nport < UB960_MAX_TX_NPORTS; ++nport) {
+			if (pad_stream_masks[nport] == 0)
+				continue;
+
+			ub960_disable_streams(sd, state,
+					      priv->hw_data->num_rxports + nport,
+					      pad_stream_masks[nport]);
+		}
+	}
+
+	v4l2_subdev_unlock_state(state);
+
+	return ret;
+}
+
+static const struct v4l2_subdev_video_ops ub960_video_ops = {
+	.s_stream = ub960_s_stream,
+};
+
+static int _ub960_set_routing(struct v4l2_subdev *sd,
+			      struct v4l2_subdev_state *state,
+			      struct v4l2_subdev_krouting *routing)
+{
+	const struct v4l2_mbus_framefmt format = {
+		.width = 640,
+		.height = 480,
+		.code = MEDIA_BUS_FMT_UYVY8_2X8,
+		.field = V4L2_FIELD_NONE,
+		.colorspace = V4L2_COLORSPACE_SRGB,
+		.ycbcr_enc = V4L2_YCBCR_ENC_601,
+		.quantization = V4L2_QUANTIZATION_LIM_RANGE,
+		.xfer_func = V4L2_XFER_FUNC_SRGB,
+	};
+	int ret;
+
+	/*
+	 * Note: we can only support up to V4L2_FRAME_DESC_ENTRY_MAX, until
+	 * frame desc is made dynamically allocated.
+	 */
+
+	if (routing->num_routes > V4L2_FRAME_DESC_ENTRY_MAX)
+		return -E2BIG;
+
+	/*
+	 * TODO: We need a new flag to validate that all streams from a sink pad
+	 * go to a single source pad.
+	 */
+	ret = v4l2_subdev_routing_validate(sd, routing,
+					   V4L2_SUBDEV_ROUTING_ONLY_1_TO_1);
+	if (ret)
+		return ret;
+
+	ret = v4l2_subdev_set_routing_with_fmt(sd, state, routing, &format);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ub960_set_routing(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_state *state,
+			     enum v4l2_subdev_format_whence which,
+			     struct v4l2_subdev_krouting *routing)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+
+	if (which == V4L2_SUBDEV_FORMAT_ACTIVE && priv->streaming)
+		return -EBUSY;
+
+	return _ub960_set_routing(sd, state, routing);
+}
+
+static int ub960_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+				struct v4l2_mbus_frame_desc *fd)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	const struct v4l2_subdev_krouting *routing;
+	struct v4l2_subdev_route *route;
+	struct v4l2_subdev_state *state;
+	int ret = 0;
+	struct device *dev = &priv->client->dev;
+	u8 vc_map[UB960_MAX_RX_NPORTS] = { 0 };
+
+	if (!ub960_pad_is_source(priv, pad))
+		return -EINVAL;
+
+	memset(fd, 0, sizeof(*fd));
+
+	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
+
+	state = v4l2_subdev_lock_and_get_active_state(&priv->sd);
+
+	ub960_get_vc_maps(priv, state, vc_map);
+
+	routing = &state->routing;
+
+	for_each_active_route(routing, route) {
+		struct v4l2_mbus_frame_desc_entry *source_entry = NULL;
+		struct v4l2_mbus_frame_desc source_fd;
+		unsigned int nport;
+		unsigned int i;
+
+		if (route->source_pad != pad)
+			continue;
+
+		nport = ub960_pad_to_port(priv, route->sink_pad);
+
+		ret = v4l2_subdev_call(priv->rxports[nport]->source_sd, pad,
+				       get_frame_desc,
+				       priv->rxports[nport]->source_sd_pad,
+				       &source_fd);
+		if (ret) {
+			dev_err(dev,
+				"Failed to get source frame desc for pad %u\n",
+				route->sink_pad);
+			goto out;
+		}
+
+		for (i = 0; i < source_fd.num_entries; ++i)
+			if (source_fd.entry[i].stream == route->sink_stream) {
+				source_entry = &source_fd.entry[i];
+				break;
+			}
+
+		if (!source_entry) {
+			dev_err(dev,
+				"Failed to find stream from source frame desc\n");
+			ret = -EPIPE;
+			goto out;
+		}
+
+		fd->entry[fd->num_entries].stream = route->source_stream;
+		fd->entry[fd->num_entries].flags = source_entry->flags;
+		fd->entry[fd->num_entries].length = source_entry->length;
+		fd->entry[fd->num_entries].pixelcode = source_entry->pixelcode;
+
+		fd->entry[fd->num_entries].bus.csi2.vc = vc_map[nport];
+
+		if (source_fd.type == V4L2_MBUS_FRAME_DESC_TYPE_CSI2) {
+			fd->entry[fd->num_entries].bus.csi2.dt =
+				source_entry->bus.csi2.dt;
+		} else {
+			const struct ub960_format_info *ub960_fmt;
+			struct v4l2_mbus_framefmt *fmt;
+
+			fmt = v4l2_subdev_state_get_stream_format(state, pad,
+								  route->source_stream);
+
+			if (!fmt) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			ub960_fmt = ub960_find_format(fmt->code);
+			if (!ub960_fmt) {
+				dev_err(dev, "Unable to find format\n");
+				ret = -EINVAL;
+				goto out;
+			}
+
+			fd->entry[fd->num_entries].bus.csi2.dt =
+				ub960_fmt->datatype;
+		}
+
+		fd->num_entries++;
+	}
+
+out:
+	v4l2_subdev_unlock_state(state);
+
+	return ret;
+}
+
+static int ub960_set_fmt(struct v4l2_subdev *sd,
+			 struct v4l2_subdev_state *state,
+			 struct v4l2_subdev_format *format)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	struct v4l2_mbus_framefmt *fmt;
+
+	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE && priv->streaming)
+		return -EBUSY;
+
+	/* No transcoding, source and sink formats must match. */
+	if (ub960_pad_is_source(priv, format->pad))
+		return v4l2_subdev_get_fmt(sd, state, format);
+
+	/* TODO: implement fmt validation */
+
+	fmt = v4l2_subdev_state_get_stream_format(state, format->pad,
+						  format->stream);
+	if (!fmt)
+		return -EINVAL;
+
+	*fmt = format->format;
+
+	fmt = v4l2_subdev_state_get_opposite_stream_format(state, format->pad,
+							   format->stream);
+	if (!fmt)
+		return -EINVAL;
+
+	*fmt = format->format;
+
+	return 0;
+}
+
+static int ub960_init_cfg(struct v4l2_subdev *sd,
+			  struct v4l2_subdev_state *state)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+
+	struct v4l2_subdev_route routes[] = {
+		{
+			.sink_pad = 0,
+			.sink_stream = 0,
+			.source_pad = priv->hw_data->num_rxports,
+			.source_stream = 0,
+			.flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE,
+		},
+	};
+
+	struct v4l2_subdev_krouting routing = {
+		.num_routes = ARRAY_SIZE(routes),
+		.routes = routes,
+	};
+
+	return _ub960_set_routing(sd, state, &routing);
+}
+
+static const struct v4l2_subdev_pad_ops ub960_pad_ops = {
+	.enable_streams = ub960_enable_streams,
+	.disable_streams = ub960_disable_streams,
+
+	.set_routing = ub960_set_routing,
+	.get_frame_desc = ub960_get_frame_desc,
+
+	.get_fmt = v4l2_subdev_get_fmt,
+	.set_fmt = ub960_set_fmt,
+
+	.init_cfg = ub960_init_cfg,
+};
+
+static int ub960_log_status(struct v4l2_subdev *sd)
+{
+	struct ub960_data *priv = sd_to_ub960(sd);
+	struct device *dev = &priv->client->dev;
+	struct v4l2_subdev_state *state;
+	unsigned int nport;
+	u8 v = 0, v1 = 0, v2 = 0;
+	char id[7];
+
+	state = v4l2_subdev_lock_and_get_active_state(sd);
+
+	for (unsigned int i = 0; i < 6; ++i)
+		ub960_read(priv, UB960_SR_FPD3_RX_ID(i), &id[i]);
+	id[6] = 0;
+
+	dev_info(dev, "ID '%s'\n", id);
+
+	for (nport = 0; nport < priv->hw_data->num_txports; ++nport) {
+		struct ub960_txport *txport = priv->txports[nport];
+
+		dev_info(dev, "TX %u\n", nport);
+
+		if (!txport) {
+			dev_info(dev, "\tNot initialized\n");
+			continue;
+		}
+
+		ub960_csiport_read(priv, nport, UB960_TR_CSI_STS, &v);
+		dev_info(dev, "\tsync %u, pass %u\n", v & (u8)BIT(1),
+			 v & (u8)BIT(0));
+
+		ub960_read(priv, UB960_SR_CSI_FRAME_COUNT_HI(nport), &v1);
+		ub960_read(priv, UB960_SR_CSI_FRAME_COUNT_LO(nport), &v2);
+		dev_info(dev, "\tframe counter %u\n", (v1 << 8) | v2);
+
+		ub960_read(priv, UB960_SR_CSI_FRAME_ERR_COUNT_HI(nport), &v1);
+		ub960_read(priv, UB960_SR_CSI_FRAME_ERR_COUNT_LO(nport), &v2);
+		dev_info(dev, "\tframe error counter %u\n", (v1 << 8) | v2);
+
+		ub960_read(priv, UB960_SR_CSI_LINE_COUNT_HI(nport), &v1);
+		ub960_read(priv, UB960_SR_CSI_LINE_COUNT_LO(nport), &v2);
+		dev_info(dev, "\tline counter %u\n", (v1 << 8) | v2);
+
+		ub960_read(priv, UB960_SR_CSI_LINE_ERR_COUNT_HI(nport), &v1);
+		ub960_read(priv, UB960_SR_CSI_LINE_ERR_COUNT_LO(nport), &v2);
+		dev_info(dev, "\tline error counter %u\n", (v1 << 8) | v2);
+	}
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+		u8 eq_level;
+		s8 strobe_pos;
+		unsigned int i;
+
+		dev_info(dev, "RX %u\n", nport);
+
+		if (!rxport) {
+			dev_info(dev, "\tNot initialized\n");
+			continue;
+		}
+
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS1, &v);
+
+		if (v & UB960_RR_RX_PORT_STS1_LOCK_STS)
+			dev_info(dev, "\tLocked\n");
+		else
+			dev_info(dev, "\tNot locked\n");
+
+		dev_info(dev, "\trx_port_sts1 %#02x\n", v);
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PORT_STS2, &v);
+		dev_info(dev, "\trx_port_sts2 %#02x\n", v);
+
+		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_HIGH, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_RX_FREQ_LOW, &v2);
+		dev_info(dev, "\tlink freq %u MHz\n",
+			 v1 * 1000000 + v2 * 1000000 / 256);
+
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_HI, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_RX_PAR_ERR_LO, &v2);
+		dev_info(dev, "\tparity errors %u\n", (v1 << 8) | v2);
+
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_COUNT_HI, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_COUNT_LO, &v2);
+		dev_info(dev, "\tlines per frame %u\n", (v1 << 8) | v2);
+
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_LEN_1, &v1);
+		ub960_rxport_read(priv, nport, UB960_RR_LINE_LEN_0, &v2);
+		dev_info(dev, "\tbytes per line %u\n", (v1 << 8) | v2);
+
+		ub960_rxport_read(priv, nport, UB960_RR_CSI_ERR_COUNTER, &v);
+		dev_info(dev, "\tcsi_err_counter %u\n", v);
+
+		/* Strobe */
+
+		ub960_read(priv, UB960_XR_AEQ_CTL1, &v);
+
+		dev_info(dev, "\t%s strobe\n",
+			 (v & UB960_XR_AEQ_CTL1_AEQ_SFILTER_EN) ? "Adaptive" :
+								  "Manual");
+
+		if (v & UB960_XR_AEQ_CTL1_AEQ_SFILTER_EN) {
+			ub960_read(priv, UB960_XR_SFILTER_CFG, &v);
+
+			dev_info(dev, "\tStrobe range [%d, %d]\n",
+				 ((v >> UB960_XR_SFILTER_CFG_SFILTER_MIN_SHIFT) & 0xf) - 7,
+				 ((v >> UB960_XR_SFILTER_CFG_SFILTER_MAX_SHIFT) & 0xf) - 7);
+		}
+
+		ub960_rxport_get_strobe_pos(priv, nport, &strobe_pos);
+
+		dev_info(dev, "\tStrobe pos %d\n", strobe_pos);
+
+		/* EQ */
+
+		ub960_rxport_read(priv, nport, UB960_RR_AEQ_BYPASS, &v);
+
+		dev_info(dev, "\t%s EQ\n",
+			 (v & UB960_RR_AEQ_BYPASS_ENABLE) ? "Manual" :
+							    "Adaptive");
+
+		if (!(v & UB960_RR_AEQ_BYPASS_ENABLE)) {
+			ub960_rxport_read(priv, nport, UB960_RR_AEQ_MIN_MAX, &v);
+
+			dev_info(dev, "\tEQ range [%u, %u]\n",
+				 (v >> UB960_RR_AEQ_MIN_MAX_AEQ_FLOOR_SHIFT) & 0xf,
+				 (v >> UB960_RR_AEQ_MIN_MAX_AEQ_MAX_SHIFT) & 0xf);
+		}
+
+		if (ub960_rxport_get_eq_level(priv, nport, &eq_level) == 0)
+			dev_info(dev, "\tEQ level %u\n", eq_level);
+
+		/* GPIOs */
+		for (i = 0; i < UB960_NUM_BC_GPIOS; ++i) {
+			u8 ctl_reg;
+			u8 ctl_shift;
+
+			ctl_reg = UB960_RR_BC_GPIO_CTL(i / 2);
+			ctl_shift = (i % 2) * 4;
+
+			ub960_rxport_read(priv, nport, ctl_reg, &v);
+
+			dev_info(dev, "\tGPIO%u: mode %u\n", i,
+				 (v >> ctl_shift) & 0xf);
+		}
+	}
+
+	v4l2_subdev_unlock_state(state);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_core_ops ub960_subdev_core_ops = {
+	.log_status = ub960_log_status,
+	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
+	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
+};
+
+static const struct v4l2_subdev_ops ub960_subdev_ops = {
+	.core = &ub960_subdev_core_ops,
+	.video = &ub960_video_ops,
+	.pad = &ub960_pad_ops,
+};
+
+static const struct media_entity_operations ub960_entity_ops = {
+	.get_fwnode_pad = v4l2_subdev_get_fwnode_pad_1_to_1,
+	.link_validate = v4l2_subdev_link_validate,
+	.has_pad_interdep = v4l2_subdev_has_pad_interdep,
+};
+
+static void ub960_enable_tpg(struct ub960_data *priv, int tpg_num)
+{
+	/*
+	 * Note: no need to write UB960_REG_IND_ACC_CTL: the only indirect
+	 * registers target we use is "CSI-2 Pattern Generator & Timing
+	 * Registers", which is the default
+	 */
+
+	/*
+	 * TPG can only provide a single stream per CSI TX port. If
+	 * multiple streams are currently enabled, only the first
+	 * one will use the TPG, other streams will be halted.
+	 */
+
+	struct v4l2_mbus_framefmt *fmt;
+	u8 vbp, vfp;
+	u16 blank_lines;
+	u16 width;
+	u16 height;
+
+	u16 bytespp = 2; /* For MEDIA_BUS_FMT_UYVY8_1X16 */
+	u8 cbars_idx = tpg_num - TEST_PATTERN_V_COLOR_BARS_1;
+	u8 num_cbars = 1 << cbars_idx;
+
+	u16 line_size;	/* Line size [bytes] */
+	u16 bar_size;	/* cbar size [bytes] */
+	u16 act_lpf;	/* active lines/frame */
+	u16 tot_lpf;	/* tot lines/frame */
+	u16 line_pd;	/* Line period in 10-ns units */
+
+	struct v4l2_subdev_state *state;
+
+	state = v4l2_subdev_get_locked_active_state(&priv->sd);
+
+	vbp = 33;
+	vfp = 10;
+	blank_lines = vbp + vfp + 2; /* total blanking lines */
+
+	fmt = v4l2_subdev_state_get_stream_format(state, 4, 0);
+	if (!fmt) {
+		dev_err(&priv->client->dev, "failed to enable TPG\n");
+		return;
+	}
+
+	width = fmt->width;
+	height = fmt->height;
+
+	line_size = width * bytespp;
+	bar_size = line_size / num_cbars;
+	act_lpf = height;
+	tot_lpf = act_lpf + blank_lines;
+	line_pd = 100000000 / 60 / tot_lpf;
+
+	/* Disable forwarding from FPD-3 RX ports */
+	ub960_read(priv, UB960_SR_FWD_CTL1, &priv->stored_fwd_ctl);
+	ub960_write(priv, UB960_SR_FWD_CTL1, 0xf << 4);
+
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_CTL,
+			UB960_IR_PGEN_CTL_PGEN_ENABLE);
+
+	/* YUV422 8bit: 2 bytes/block, CSI-2 data type 0x1e */
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_CFG,
+			cbars_idx << 4 | 0x2);
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_CSI_DI,
+			0x1e);
+
+	ub960_write_ind16(priv, UB960_IND_TARGET_PAT_GEN,
+			  UB960_IR_PGEN_LINE_SIZE1, line_size);
+	ub960_write_ind16(priv, UB960_IND_TARGET_PAT_GEN,
+			  UB960_IR_PGEN_BAR_SIZE1, bar_size);
+	ub960_write_ind16(priv, UB960_IND_TARGET_PAT_GEN,
+			  UB960_IR_PGEN_ACT_LPF1, act_lpf);
+	ub960_write_ind16(priv, UB960_IND_TARGET_PAT_GEN,
+			  UB960_IR_PGEN_TOT_LPF1, tot_lpf);
+	ub960_write_ind16(priv, UB960_IND_TARGET_PAT_GEN,
+			  UB960_IR_PGEN_LINE_PD1, line_pd);
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_VBP, vbp);
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_VFP, vfp);
+}
+
+static void ub960_disable_tpg(struct ub960_data *priv)
+{
+	/* TPG off, enable forwarding from FPD-3 RX ports */
+	ub960_write(priv, UB960_SR_FWD_CTL1, priv->stored_fwd_ctl);
+
+	ub960_write_ind(priv, UB960_IND_TARGET_PAT_GEN, UB960_IR_PGEN_CTL, 0x00);
+}
+
+static int ub960_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ub960_data *priv =
+		container_of(ctrl->handler, struct ub960_data, ctrl_handler);
+
+	switch (ctrl->id) {
+	case V4L2_CID_TEST_PATTERN:
+		if (ctrl->val == 0)
+			ub960_disable_tpg(priv);
+		else
+			ub960_enable_tpg(priv, ctrl->val);
+		break;
+	}
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops ub960_ctrl_ops = {
+	.s_ctrl = ub960_s_ctrl,
+};
+
+/* -----------------------------------------------------------------------------
+ * Core
+ */
+
+static irqreturn_t ub960_handle_events(int irq, void *arg)
+{
+	struct ub960_data *priv = arg;
+	unsigned int i;
+	u8 int_sts;
+	int ret;
+
+	ret = ub960_read(priv, UB960_SR_INTERRUPT_STS, &int_sts);
+
+	if (!ret && int_sts) {
+		u8 fwd_sts;
+
+		dev_dbg(&priv->client->dev, "INTERRUPT_STS %x\n", int_sts);
+
+		ub960_read(priv, UB960_SR_FWD_STS, &fwd_sts);
+
+		dev_dbg(&priv->client->dev, "FWD_STS %#02x\n", fwd_sts);
+
+		for (i = 0; i < priv->hw_data->num_txports; ++i) {
+			if (int_sts & UB960_SR_INTERRUPT_STS_IS_CSI_TX(i))
+				ub960_csi_handle_events(priv, i);
+		}
+
+		for (i = 0; i < priv->hw_data->num_rxports; i++) {
+			if (!priv->rxports[i])
+				continue;
+
+			if (int_sts & UB960_SR_INTERRUPT_STS_IS_RX(i))
+				ub960_rxport_handle_events(priv, i);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void ub960_handler_work(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct ub960_data *priv =
+		container_of(dwork, struct ub960_data, poll_work);
+
+	ub960_handle_events(0, priv);
+
+	schedule_delayed_work(&priv->poll_work,
+			      msecs_to_jiffies(UB960_POLL_TIME_MS));
+}
+
+static void ub960_txport_free_ports(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_txports; nport++) {
+		struct ub960_txport *txport = priv->txports[nport];
+
+		if (!txport)
+			continue;
+
+		kfree(txport);
+		priv->txports[nport] = NULL;
+	}
+}
+
+static void ub960_rxport_free_ports(struct ub960_data *priv)
+{
+	unsigned int nport;
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; nport++) {
+		struct ub960_rxport *rxport = priv->rxports[nport];
+
+		if (!rxport)
+			continue;
+
+		fwnode_handle_put(rxport->source_ep_fwnode);
+		fwnode_handle_put(rxport->remote_fwnode);
+
+		kfree(rxport);
+		priv->rxports[nport] = NULL;
+	}
+}
+
+static int ub960_parse_dt_base(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	size_t table_size;
+	u16 *aliases;
+	int ret;
+
+	ret = fwnode_property_count_u16(dev_fwnode(dev), "i2c-alias-pool");
+	if (ret < 0) {
+		dev_err(dev, "Failed to count 'i2c-alias-pool' property: %d\n",
+			ret);
+		return ret;
+	}
+
+	table_size = ret;
+	priv->atr_alias_table.num_entries = ret;
+
+	if (!table_size)
+		return 0;
+
+	priv->atr_alias_table.entries =
+		devm_kcalloc(dev, table_size,
+			     sizeof(struct atr_alias_table_entry), GFP_KERNEL);
+	if (!priv->atr_alias_table.entries)
+		return -ENOMEM;
+
+	aliases = kcalloc(table_size, sizeof(u16), GFP_KERNEL);
+	if (!aliases)
+		return -ENOMEM;
+
+	ret = fwnode_property_read_u16_array(dev_fwnode(dev), "i2c-alias-pool",
+					     aliases, table_size);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read 'i2c-alias-pool' property: %d\n",
+			ret);
+		kfree(aliases);
+		return ret;
+	}
+
+	for (unsigned int i = 0; i < table_size; ++i)
+		priv->atr_alias_table.entries[i].alias_id = aliases[i];
+
+	kfree(aliases);
+
+	dev_dbg(dev, "i2c-alias-pool has %zu aliases", table_size);
+
+	return 0;
+}
+
+static int
+ub960_parse_dt_rxport_link_properties(struct ub960_data *priv,
+				      struct fwnode_handle *link_fwnode,
+				      struct ub960_rxport *rxport)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int nport = rxport->nport;
+	u32 rx_mode;
+	u32 cdr_mode;
+	s32 strobe_pos;
+	u32 eq_level;
+	u32 ser_i2c_alias;
+	int ret;
+
+	ret = fwnode_property_read_u32(link_fwnode, "ti,cdr-mode", &cdr_mode);
+	if (ret == -EINVAL) {
+		cdr_mode = RXPORT_CDR_FPD3;
+	} else if (ret < 0) {
+		dev_err(dev, "rx%u: failed to read 'ti,cdr-mode': %d\n", nport,
+			ret);
+		return ret;
+	}
+
+	if (cdr_mode > RXPORT_CDR_LAST) {
+		dev_err(dev, "rx%u: bad 'ti,cdr-mode' %u\n", nport, cdr_mode);
+		return -EINVAL;
+	}
+
+	if (!priv->hw_data->is_fpdlink4 && cdr_mode == RXPORT_CDR_FPD4) {
+		dev_err(dev, "rx%u: FPD-Link 4 CDR not supported\n", nport);
+		return -EINVAL;
+	}
+
+	rxport->cdr_mode = cdr_mode;
+
+	ret = fwnode_property_read_u32(link_fwnode, "ti,rx-mode", &rx_mode);
+	if (ret < 0) {
+		dev_err(dev, "rx%u: failed to read 'ti,rx-mode': %d\n", nport,
+			ret);
+		return ret;
+	}
+
+	if (rx_mode > RXPORT_MODE_LAST) {
+		dev_err(dev, "rx%u: bad 'ti,rx-mode' %u\n", nport, rx_mode);
+		return -EINVAL;
+	}
+
+	rxport->rx_mode = rx_mode;
+
+	/* EQ & Strobe related */
+
+	/* Defaults */
+	rxport->eq.manual_eq = false;
+	rxport->eq.aeq.eq_level_min = UB960_MIN_EQ_LEVEL;
+	rxport->eq.aeq.eq_level_max = UB960_MAX_EQ_LEVEL;
+
+	ret = fwnode_property_read_u32(link_fwnode, "ti,strobe-pos",
+				       &strobe_pos);
+	if (ret) {
+		if (ret != -EINVAL) {
+			dev_err(dev,
+				"rx%u: failed to read 'ti,strobe-pos': %d\n",
+				nport, ret);
+			return ret;
+		}
+	} else if (strobe_pos < UB960_MIN_MANUAL_STROBE_POS ||
+		   strobe_pos > UB960_MAX_MANUAL_STROBE_POS) {
+		dev_err(dev, "rx%u: illegal 'strobe-pos' value: %d\n", nport,
+			strobe_pos);
+	} else {
+		// NOTE: ignored unless global manual strobe pos is set
+		rxport->eq.strobe_pos = strobe_pos;
+		if (!priv->strobe.manual)
+			dev_warn(dev,
+				 "rx%u: 'ti,strobe-pos' ignored as 'ti,manual-strobe' not set\n",
+				 nport);
+	}
+
+	ret = fwnode_property_read_u32(link_fwnode, "ti,eq-level", &eq_level);
+	if (ret) {
+		if (ret != -EINVAL) {
+			dev_err(dev, "rx%u: failed to read 'ti,eq-level': %d\n",
+				nport, ret);
+			return ret;
+		}
+	} else if (eq_level > UB960_MAX_EQ_LEVEL) {
+		dev_err(dev, "rx%u: illegal 'ti,eq-level' value: %d\n", nport,
+			eq_level);
+	} else {
+		rxport->eq.manual_eq = true;
+		rxport->eq.manual.eq_level = eq_level;
+	}
+
+	ret = fwnode_property_read_u32(link_fwnode, "i2c-alias",
+				       &ser_i2c_alias);
+	if (ret) {
+		dev_err(dev, "rx%u: failed to read 'i2c-alias': %d\n", nport,
+			ret);
+		return ret;
+	}
+	rxport->ser_alias = ser_i2c_alias;
+
+	rxport->remote_fwnode = fwnode_get_named_child_node(link_fwnode, "serializer");
+	if (!rxport->remote_fwnode) {
+		dev_err(dev, "rx%u: missing 'serializer' node\n", nport);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ub960_parse_dt_rxport_ep_properties(struct ub960_data *priv,
+					       struct fwnode_handle *ep_fwnode,
+					       struct ub960_rxport *rxport)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int nport = rxport->nport;
+	int ret;
+	u32 v;
+
+	rxport->source_ep_fwnode = fwnode_graph_get_remote_endpoint(ep_fwnode);
+	if (!rxport->source_ep_fwnode) {
+		dev_err(dev, "rx%u: no remote endpoint\n", nport);
+		return -ENODEV;
+	}
+
+	/* We currently have properties only for RAW modes */
+
+	switch (rxport->rx_mode) {
+	case RXPORT_MODE_RAW10:
+	case RXPORT_MODE_RAW12_HF:
+	case RXPORT_MODE_RAW12_LF:
+		break;
+	default:
+		return 0;
+	}
+
+	ret = fwnode_property_read_u32(ep_fwnode, "hsync-active", &v);
+	if (ret) {
+		dev_err(dev, "rx%u: failed to parse 'hsync-active': %d\n",
+			nport, ret);
+		goto err_put_source_ep_fwnode;
+	}
+
+	rxport->lv_fv_pol |= v ? UB960_RR_PORT_CONFIG2_LV_POL_LOW : 0;
+
+	ret = fwnode_property_read_u32(ep_fwnode, "vsync-active", &v);
+	if (ret) {
+		dev_err(dev, "rx%u: failed to parse 'vsync-active': %d\n",
+			nport, ret);
+		goto err_put_source_ep_fwnode;
+	}
+
+	rxport->lv_fv_pol |= v ? UB960_RR_PORT_CONFIG2_FV_POL_LOW : 0;
+
+	return 0;
+
+err_put_source_ep_fwnode:
+	fwnode_handle_put(rxport->source_ep_fwnode);
+	return ret;
+}
+
+static int ub960_parse_dt_rxport(struct ub960_data *priv, unsigned int nport,
+				 struct fwnode_handle *link_fwnode,
+				 struct fwnode_handle *ep_fwnode)
+{
+	const char *vpoc_names[UB960_MAX_RX_NPORTS] = { "vpoc0", "vpoc1",
+							"vpoc2", "vpoc3" };
+	struct device *dev = &priv->client->dev;
+	struct ub960_rxport *rxport;
+	int ret;
+
+	rxport = kzalloc(sizeof(*rxport), GFP_KERNEL);
+	if (!rxport)
+		return -ENOMEM;
+
+	priv->rxports[nport] = rxport;
+
+	rxport->nport = nport;
+	rxport->priv = priv;
+
+	ret = ub960_parse_dt_rxport_link_properties(priv, link_fwnode, rxport);
+	if (ret)
+		goto err_free_rxport;
+
+	rxport->vpoc = devm_regulator_get_optional(dev, vpoc_names[nport]);
+	if (IS_ERR(rxport->vpoc)) {
+		ret = PTR_ERR(rxport->vpoc);
+		if (ret == -ENODEV) {
+			rxport->vpoc = NULL;
+		} else {
+			dev_err(dev, "rx%u: failed to get VPOC supply: %d\n",
+				nport, ret);
+			goto err_put_remote_fwnode;
+		}
+	}
+
+	ret = ub960_parse_dt_rxport_ep_properties(priv, ep_fwnode, rxport);
+	if (ret)
+		goto err_put_remote_fwnode;
+
+	return 0;
+
+err_put_remote_fwnode:
+	fwnode_handle_put(rxport->remote_fwnode);
+err_free_rxport:
+	priv->rxports[nport] = NULL;
+	kfree(rxport);
+	return ret;
+}
+
+static struct fwnode_handle *
+ub960_fwnode_get_link_by_regs(struct fwnode_handle *links_fwnode,
+			      unsigned int nport)
+{
+	struct fwnode_handle *link_fwnode;
+	int ret;
+
+	fwnode_for_each_child_node(links_fwnode, link_fwnode) {
+		u32 link_num;
+
+		if (strncmp(fwnode_get_name(link_fwnode), "link@", 5) != 0)
+			continue;
+
+		ret = fwnode_property_read_u32(link_fwnode, "reg", &link_num);
+		if (ret)
+			return NULL;
+
+		if (nport == link_num) {
+			fwnode_handle_put(link_fwnode);
+			return link_fwnode;
+		}
+	}
+
+	return NULL;
+}
+
+static int ub960_parse_dt_rxports(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	struct fwnode_handle *links_fwnode;
+	unsigned int nport;
+	int ret;
+
+	links_fwnode = fwnode_get_named_child_node(dev_fwnode(dev), "links");
+	if (!links_fwnode) {
+		dev_err(dev, "'links' node missing\n");
+		return -ENODEV;
+	}
+
+	/* Defaults, recommended by TI */
+	priv->strobe.min = 2;
+	priv->strobe.max = 3;
+
+	priv->strobe.manual = fwnode_property_read_bool(links_fwnode, "ti,manual-strobe");
+
+	for (nport = 0; nport < priv->hw_data->num_rxports; ++nport) {
+		struct fwnode_handle *link_fwnode;
+		struct fwnode_handle *ep_fwnode;
+
+		link_fwnode = ub960_fwnode_get_link_by_regs(links_fwnode, nport);
+		if (!link_fwnode)
+			continue;
+
+		ep_fwnode = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev),
+							    nport, 0, 0);
+		if (!ep_fwnode) {
+			fwnode_handle_put(link_fwnode);
+			continue;
+		}
+
+		ret = ub960_parse_dt_rxport(priv, nport, link_fwnode,
+					    ep_fwnode);
+
+		fwnode_handle_put(link_fwnode);
+		fwnode_handle_put(ep_fwnode);
+
+		if (ret) {
+			dev_err(dev, "rx%u: failed to parse RX port\n", nport);
+			goto err_put_links;
+		}
+	}
+
+	fwnode_handle_put(links_fwnode);
+
+	return 0;
+
+err_put_links:
+	fwnode_handle_put(links_fwnode);
+
+	return ret;
+}
+
+static int ub960_parse_dt_txports(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	u32 nport;
+	int ret;
+
+	for (nport = 0; nport < priv->hw_data->num_txports; ++nport) {
+		struct fwnode_handle *ep_fwnode;
+
+		ep_fwnode = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev),
+			nport + priv->hw_data->num_rxports, 0, 0);
+		if (!ep_fwnode)
+			continue;
+
+		ret = ub960_parse_dt_txport(priv, ep_fwnode, nport);
+
+		fwnode_handle_put(ep_fwnode);
+
+		if (ret)
+			break;
+	}
+
+	return 0;
+}
+
+static int ub960_parse_dt(struct ub960_data *priv)
+{
+	int ret;
+
+	ret = ub960_parse_dt_base(priv);
+	if (ret)
+		return ret;
+
+	ret = ub960_parse_dt_rxports(priv);
+	if (ret)
+		return ret;
+
+	ret = ub960_parse_dt_txports(priv);
+	if (ret)
+		goto err_free_rxports;
+
+	return 0;
+
+err_free_rxports:
+	ub960_rxport_free_ports(priv);
+
+	return ret;
+}
+
+static int ub960_notify_bound(struct v4l2_async_notifier *notifier,
+			      struct v4l2_subdev *subdev,
+			      struct v4l2_async_subdev *asd)
+{
+	struct ub960_data *priv = sd_to_ub960(notifier->sd);
+	struct ub960_rxport *rxport = to_ub960_asd(asd)->rxport;
+	struct device *dev = &priv->client->dev;
+	u8 nport = rxport->nport;
+	unsigned int i;
+	int ret;
+
+	ret = media_entity_get_fwnode_pad(&subdev->entity,
+					  rxport->source_ep_fwnode,
+					  MEDIA_PAD_FL_SOURCE);
+	if (ret < 0) {
+		dev_err(dev, "Failed to find pad for %s\n", subdev->name);
+		return ret;
+	}
+
+	rxport->source_sd = subdev;
+	rxport->source_sd_pad = ret;
+
+	ret = media_create_pad_link(&rxport->source_sd->entity,
+				    rxport->source_sd_pad, &priv->sd.entity,
+				    nport,
+				    MEDIA_LNK_FL_ENABLED |
+					    MEDIA_LNK_FL_IMMUTABLE);
+	if (ret) {
+		dev_err(dev, "Unable to link %s:%u -> %s:%u\n",
+			rxport->source_sd->name, rxport->source_sd_pad,
+			priv->sd.name, nport);
+		return ret;
+	}
+
+	dev_dbg(dev, "Bound %s pad: %u on index %u\n", subdev->name,
+		rxport->source_sd_pad, nport);
+
+	for (i = 0; i < priv->hw_data->num_rxports; ++i) {
+		if (priv->rxports[i] && !priv->rxports[i]->source_sd) {
+			dev_dbg(dev, "Waiting for more subdevs to be bound\n");
+			return 0;
+		}
+	}
+
+	dev_dbg(dev, "All subdevs bound\n");
+
+	return 0;
+}
+
+static void ub960_notify_unbind(struct v4l2_async_notifier *notifier,
+				struct v4l2_subdev *subdev,
+				struct v4l2_async_subdev *asd)
+{
+	struct ub960_rxport *rxport = to_ub960_asd(asd)->rxport;
+
+	rxport->source_sd = NULL;
+}
+
+static const struct v4l2_async_notifier_operations ub960_notify_ops = {
+	.bound = ub960_notify_bound,
+	.unbind = ub960_notify_unbind,
+};
+
+static int ub960_v4l2_notifier_register(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int i;
+	int ret;
+
+	v4l2_async_nf_init(&priv->notifier);
+
+	for (i = 0; i < priv->hw_data->num_rxports; ++i) {
+		struct ub960_rxport *rxport = priv->rxports[i];
+		struct ub960_asd *asd;
+
+		if (!rxport)
+			continue;
+
+		asd = v4l2_async_nf_add_fwnode(&priv->notifier,
+					       rxport->source_ep_fwnode,
+					       struct ub960_asd);
+		if (IS_ERR(asd)) {
+			dev_err(dev, "Failed to add subdev for source %u: %ld",
+				i, PTR_ERR(asd));
+			v4l2_async_nf_cleanup(&priv->notifier);
+			return PTR_ERR(asd);
+		}
+
+		asd->rxport = rxport;
+	}
+
+	priv->notifier.ops = &ub960_notify_ops;
+
+	ret = v4l2_async_subdev_nf_register(&priv->sd, &priv->notifier);
+	if (ret) {
+		dev_err(dev, "Failed to register subdev_notifier");
+		v4l2_async_nf_cleanup(&priv->notifier);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ub960_v4l2_notifier_unregister(struct ub960_data *priv)
+{
+	v4l2_async_nf_unregister(&priv->notifier);
+	v4l2_async_nf_cleanup(&priv->notifier);
+}
+
+static int ub960_create_subdev(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int i;
+	int ret;
+
+	v4l2_i2c_subdev_init(&priv->sd, priv->client, &ub960_subdev_ops);
+	v4l2_ctrl_handler_init(&priv->ctrl_handler,
+			       ARRAY_SIZE(ub960_tpg_qmenu) - 1);
+	priv->sd.ctrl_handler = &priv->ctrl_handler;
+
+	v4l2_ctrl_new_std_menu_items(&priv->ctrl_handler, &ub960_ctrl_ops,
+				     V4L2_CID_TEST_PATTERN,
+				     ARRAY_SIZE(ub960_tpg_qmenu) - 1, 0, 0,
+				     ub960_tpg_qmenu);
+
+	v4l2_ctrl_new_int_menu(&priv->ctrl_handler, NULL, V4L2_CID_LINK_FREQ,
+			       ARRAY_SIZE(priv->tx_link_freq) - 1, 0,
+			       priv->tx_link_freq);
+
+	if (priv->ctrl_handler.error) {
+		ret = priv->ctrl_handler.error;
+		goto err_free_ctrl;
+	}
+
+	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
+			  V4L2_SUBDEV_FL_HAS_EVENTS | V4L2_SUBDEV_FL_STREAMS;
+	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+	priv->sd.entity.ops = &ub960_entity_ops;
+
+	for (i = 0; i < priv->hw_data->num_rxports + priv->hw_data->num_txports; i++) {
+		priv->pads[i].flags = ub960_pad_is_sink(priv, i) ?
+					      MEDIA_PAD_FL_SINK :
+					      MEDIA_PAD_FL_SOURCE;
+	}
+
+	ret = media_entity_pads_init(&priv->sd.entity,
+				     priv->hw_data->num_rxports +
+					     priv->hw_data->num_txports,
+				     priv->pads);
+	if (ret)
+		goto err_free_ctrl;
+
+	priv->sd.state_lock = priv->sd.ctrl_handler->lock;
+
+	ret = v4l2_subdev_init_finalize(&priv->sd);
+	if (ret)
+		goto err_entity_cleanup;
+
+	ret = ub960_v4l2_notifier_register(priv);
+	if (ret) {
+		dev_err(dev, "v4l2 subdev notifier register failed: %d\n", ret);
+		goto err_free_state;
+	}
+
+	ret = v4l2_async_register_subdev(&priv->sd);
+	if (ret) {
+		dev_err(dev, "v4l2_async_register_subdev error: %d\n", ret);
+		goto err_unreg_notif;
+	}
+
+	return 0;
+
+err_unreg_notif:
+	ub960_v4l2_notifier_unregister(priv);
+err_free_state:
+	v4l2_subdev_cleanup(&priv->sd);
+err_entity_cleanup:
+	media_entity_cleanup(&priv->sd.entity);
+err_free_ctrl:
+	v4l2_ctrl_handler_free(&priv->ctrl_handler);
+
+	return ret;
+}
+
+static void ub960_destroy_subdev(struct ub960_data *priv)
+{
+	ub960_v4l2_notifier_unregister(priv);
+	v4l2_async_unregister_subdev(&priv->sd);
+
+	v4l2_subdev_cleanup(&priv->sd);
+
+	media_entity_cleanup(&priv->sd.entity);
+	v4l2_ctrl_handler_free(&priv->ctrl_handler);
+}
+
+static const struct regmap_config ub960_regmap_config = {
+	.name = "ds90ub960",
+
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = 0xff,
+
+	/*
+	 * We do locking in the driver to cover the TX/RX port selection and the
+	 * indirect register access.
+	 */
+	.disable_locking = true,
+};
+
+static void ub960_reset(struct ub960_data *priv, bool reset_regs)
+{
+	struct device *dev = &priv->client->dev;
+	unsigned int v;
+	int ret;
+	u8 bit;
+
+	bit = reset_regs ? UB960_SR_RESET_DIGITAL_RESET1 :
+			   UB960_SR_RESET_DIGITAL_RESET0;
+
+	ub960_write(priv, UB960_SR_RESET, bit);
+
+	mutex_lock(&priv->reg_lock);
+
+	ret = regmap_read_poll_timeout(priv->regmap, UB960_SR_RESET, v,
+				       (v & bit) == 0, 2000, 100000);
+
+	mutex_unlock(&priv->reg_lock);
+
+	if (ret)
+		dev_err(dev, "reset failed: %d\n", ret);
+}
+
+static int ub960_get_hw_resources(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+
+	priv->regmap = devm_regmap_init_i2c(priv->client, &ub960_regmap_config);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	priv->vddio = devm_regulator_get(dev, "vddio");
+	if (IS_ERR(priv->vddio))
+		return dev_err_probe(dev, PTR_ERR(priv->vddio),
+				     "cannot get VDDIO regulator\n");
+
+	/* get power-down pin from DT */
+	priv->pd_gpio =
+		devm_gpiod_get_optional(dev, "powerdown", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->pd_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->pd_gpio),
+				     "Cannot get powerdown GPIO\n");
+
+	priv->refclk = devm_clk_get(dev, "refclk");
+	if (IS_ERR(priv->refclk))
+		return dev_err_probe(dev, PTR_ERR(priv->refclk),
+				     "Cannot get REFCLK\n");
+
+	return 0;
+}
+
+static int ub960_enable_core_hw(struct ub960_data *priv)
+{
+	struct device *dev = &priv->client->dev;
+	u8 rev_mask;
+	int ret;
+	u8 dev_sts;
+	u8 refclk_freq;
+
+	ret = regulator_enable(priv->vddio);
+	if (ret) {
+		dev_err(dev, "failed to enable VDDIO regulator\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->refclk);
+	if (ret) {
+		dev_err(dev, "Failed to enable refclk: %d\n", ret);
+		goto err_disable_vddio;
+	}
+
+	if (priv->pd_gpio) {
+		gpiod_set_value_cansleep(priv->pd_gpio, 1);
+		/* wait min 2 ms for reset to complete */
+		usleep_range(2000, 5000);
+		gpiod_set_value_cansleep(priv->pd_gpio, 0);
+		/* wait min 2 ms for power up to finish */
+		usleep_range(2000, 5000);
+	}
+
+	ub960_reset(priv, true);
+
+	/* Runtime check register accessibility */
+	ret = ub960_read(priv, UB960_SR_REV_MASK, &rev_mask);
+	if (ret) {
+		dev_err(dev, "Cannot read first register (%d), abort\n", ret);
+		goto err_pd_gpio;
+	}
+
+	dev_dbg(dev, "Found %s (rev/mask %#04x)\n", priv->hw_data->model,
+		rev_mask);
+
+	ret = ub960_read(priv, UB960_SR_DEVICE_STS, &dev_sts);
+	if (ret)
+		goto err_pd_gpio;
+
+	ret = ub960_read(priv, UB960_XR_REFCLK_FREQ, &refclk_freq);
+	if (ret)
+		goto err_pd_gpio;
+
+	dev_dbg(dev, "refclk valid %u freq %u MHz (clk fw freq %lu MHz)\n",
+		!!(dev_sts & BIT(4)), refclk_freq,
+		clk_get_rate(priv->refclk) / 1000000);
+
+	/* Disable all RX ports by default */
+	ub960_write(priv, UB960_SR_RX_PORT_CTL, 0);
+
+	return 0;
+
+err_pd_gpio:
+	if (priv->pd_gpio)
+		gpiod_set_value_cansleep(priv->pd_gpio, 1);
+
+	clk_disable_unprepare(priv->refclk);
+err_disable_vddio:
+	regulator_disable(priv->vddio);
+
+	return ret;
+}
+
+static void ub960_disable_core_hw(struct ub960_data *priv)
+{
+	if (priv->pd_gpio)
+		gpiod_set_value_cansleep(priv->pd_gpio, 1);
+
+	clk_disable_unprepare(priv->refclk);
+
+	regulator_disable(priv->vddio);
+}
+
+static int ub960_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct ub960_data *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+
+	priv->hw_data = of_device_get_match_data(dev);
+	if (!priv->hw_data)
+		return -ENODEV;
+
+	mutex_init(&priv->reg_lock);
+	mutex_init(&priv->atr_alias_table.lock);
+
+	INIT_DELAYED_WORK(&priv->poll_work, ub960_handler_work);
+
+	/*
+	 * Initialize these to invalid values so that the first reg writes will
+	 * configure the target.
+	 */
+	priv->current_indirect_target = 0xff;
+	priv->current_read_rxport = 0xff;
+	priv->current_write_rxport_mask = 0xff;
+	priv->current_read_csiport = 0xff;
+	priv->current_write_csiport_mask = 0xff;
+
+	ret = ub960_get_hw_resources(priv);
+	if (ret)
+		goto err_mutex_destroy;
+
+	ret = ub960_enable_core_hw(priv);
+	if (ret)
+		goto err_mutex_destroy;
+
+	/* release GPIO lock */
+	if (priv->hw_data->is_ub9702)
+		ub960_update_bits(priv, UB960_SR_RESET,
+				  UB960_SR_RESET_GPIO_LOCK_RELEASE,
+				  UB960_SR_RESET_GPIO_LOCK_RELEASE);
+
+	ret = ub960_parse_dt(priv);
+	if (ret)
+		goto err_disable_core_hw;
+
+	ret = ub960_init_tx_ports(priv);
+	if (ret)
+		goto err_free_ports;
+
+	ret = ub960_rxport_enable_vpocs(priv);
+	if (ret)
+		goto err_free_ports;
+
+	ret = ub960_init_rx_ports(priv);
+	if (ret)
+		goto err_disable_vpocs;
+
+	ub960_reset(priv, false);
+
+	ub960_rxport_wait_locks(priv, 0xf, NULL);
+
+	/*
+	 * Clear any errors caused by switching the RX port settings while
+	 * probing.
+	 */
+	ub960_clear_rx_errors(priv);
+
+	ret = ub960_init_atr(priv);
+	if (ret)
+		goto err_disable_vpocs;
+
+	ret = ub960_rxport_add_serializers(priv);
+	if (ret)
+		goto err_uninit_atr;
+
+	ret = ub960_create_subdev(priv);
+	if (ret)
+		goto err_free_sers;
+
+	if (client->irq)
+		dev_warn(dev, "irq support not implemented, using polling\n");
+
+	schedule_delayed_work(&priv->poll_work,
+			      msecs_to_jiffies(UB960_POLL_TIME_MS));
+
+	return 0;
+
+err_free_sers:
+	ub960_rxport_remove_serializers(priv);
+err_uninit_atr:
+	ub960_uninit_atr(priv);
+err_disable_vpocs:
+	ub960_rxport_disable_vpocs(priv);
+err_free_ports:
+	ub960_rxport_free_ports(priv);
+	ub960_txport_free_ports(priv);
+err_disable_core_hw:
+	ub960_disable_core_hw(priv);
+err_mutex_destroy:
+	mutex_destroy(&priv->atr_alias_table.lock);
+	mutex_destroy(&priv->reg_lock);
+	return ret;
+}
+
+static void ub960_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ub960_data *priv = sd_to_ub960(sd);
+
+	cancel_delayed_work_sync(&priv->poll_work);
+
+	ub960_destroy_subdev(priv);
+	ub960_rxport_remove_serializers(priv);
+	ub960_uninit_atr(priv);
+	ub960_rxport_disable_vpocs(priv);
+	ub960_rxport_free_ports(priv);
+	ub960_txport_free_ports(priv);
+	ub960_disable_core_hw(priv);
+	mutex_destroy(&priv->atr_alias_table.lock);
+	mutex_destroy(&priv->reg_lock);
+}
+
+static const struct ub960_hw_data ds90ub960_hw = {
+	.model = "ub960",
+	.num_rxports = 4,
+	.num_txports = 2,
+};
+
+static const struct ub960_hw_data ds90ub9702_hw = {
+	.model = "ub9702",
+	.num_rxports = 4,
+	.num_txports = 2,
+	.is_ub9702 = true,
+	.is_fpdlink4 = true,
+};
+
+static const struct i2c_device_id ub960_id[] = {
+	{ "ds90ub960-q1", 0 },
+	{ "ds90ub9702-q1", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ub960_id);
+
+static const struct of_device_id ub960_dt_ids[] = {
+	{ .compatible = "ti,ds90ub960-q1", .data = &ds90ub960_hw },
+	{ .compatible = "ti,ds90ub9702-q1", .data = &ds90ub9702_hw },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ub960_dt_ids);
+
+static struct i2c_driver ds90ub960_driver = {
+	.probe_new	= ub960_probe,
+	.remove		= ub960_remove,
+	.id_table	= ub960_id,
+	.driver = {
+		.name	= "ds90ub960",
+		.owner = THIS_MODULE,
+		.of_match_table = ub960_dt_ids,
+	},
+};
+module_i2c_driver(ds90ub960_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Texas Instruments FPD-Link III/IV Deserializers Driver");
+MODULE_AUTHOR("Luca Ceresoli <luca@lucaceresoli.net>");
+MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>");
+MODULE_IMPORT_NS(I2C_ATR);
diff --git a/include/media/i2c/ds90ub9xx.h b/include/media/i2c/ds90ub9xx.h
new file mode 100644
index 000000000000..42d47d732c03
--- /dev/null
+++ b/include/media/i2c/ds90ub9xx.h
@@ -0,0 +1,16 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __MEDIA_I2C_DS90UB9XX_H__
+#define __MEDIA_I2C_DS90UB9XX_H__
+
+#include <linux/types.h>
+
+struct i2c_atr;
+
+struct ds90ub9xx_platform_data {
+	u32 port;
+	struct i2c_atr *atr;
+	unsigned long bc_rate;
+};
+
+#endif /* __MEDIA_I2C_DS90UB9XX_H__ */