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[v5,0/5] Microchip TCB Capture driver

Message ID 20200519083716.938384-1-kamel.bouhara@bootlin.com
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Series Microchip TCB Capture driver | expand

Message

Kamel Bouhara May 19, 2020, 8:37 a.m. UTC
Hello,

Here is a new counter driver to support Microchip TCB capture devices.

Each SoC has two TCB blocks, each one including three independent
channels.The following series adds support for two counter modes:
increase and quadrature decoder.

As for the atmel clocksource and pwm, the counter driver needs to fill
some tcb capabilities in order to operate with the right configuration.
This is achieved in first patch of this series.

Please feel free to comment.

Cheers,

Changes in v5:
 - Fix duplicate keys errors in yaml dt-schema

Changes in v4:
 - Use existing binding to document capture mode of the Microchip TCBs.

Changes in v3:
 - Updated the brand name: s/atmel/microchip/.
 - Added missing kernel doc for new elements introduced in structure
   atmel_tcb_config.
 - Removed useless blank line
 - Added an explicit clock removing path using devm_add_action_or_reset

Changes in v2:
 - Fixed first patch not applying on mainline
 - Updated return code to -EINVAL when user is requesting qdec mode on
   a counter device not supporting it.
 - Added an error case returning -EINVAL when action edge is performed
   in
   qdec mode.
 - Removed no need to explicity setting ops to NULL from static struct
   as
   it is the default value.
 - Changed confusing code by using snprintf for the sake of clarity.
 - Changed code to use ARRAY_SIZE so that future reviewers will know
   that num_counts matches what's in the atmel_tc_count array without
   having to check so themselves.
 - Fixed errors reported by dt_binding_check

Alexandre Belloni (2):
  dt-bindings: atmel-tcb: convert bindings to json-schema
  dt-bindings: microchip: atmel,at91rm9200-tcb: add sama5d2 compatible

Kamel Bouhara (3):
  ARM: at91: add atmel tcb capabilities
  dt-bindings: counter: microchip-tcb-capture counter
  counter: Add microchip TCB capture counter

 .../devicetree/bindings/mfd/atmel-tcb.txt     |  56 ---
 .../soc/microchip/atmel,at91rm9200-tcb.yaml   | 176 ++++++++
 drivers/counter/Kconfig                       |  11 +
 drivers/counter/Makefile                      |   1 +
 drivers/counter/microchip-tcb-capture.c       | 397 ++++++++++++++++++
 include/soc/at91/atmel_tcb.h                  |   5 +
 6 files changed, 590 insertions(+), 56 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/mfd/atmel-tcb.txt
 create mode 100644 Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
 create mode 100644 drivers/counter/microchip-tcb-capture.c

--
2.25.0

Comments

Jonathan Cameron May 24, 2020, 3:16 p.m. UTC | #1
On Tue, 19 May 2020 10:37:16 +0200
Kamel Bouhara <kamel.bouhara@bootlin.com> wrote:

> This drivers allows to use the capture mode of the Timer Counter Block
> hardware block available in Microchip SoCs through the counter subsystem.
> 
> Two functions of the counter are supported for the moment: period
> capture and quadrature decoder. The latter is only supported by the
> SAMA5 series of SoCs.
> 
> For the period capture mode a basic setup has been chosen that will
> reset the counter each time the period is actually reached. Of course
> the device offers much more possibilities.
> 
> For quadrature mode, both channel 0 and 1 must be configured even if we
> only capture the position (no revolution/rotation).
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>

Looks good to me.  After reviews from William, DT and maybe
something from SoC side if intent is I'm taking this.

Jonathan

> ---
>  drivers/counter/Kconfig                 |  11 +
>  drivers/counter/Makefile                |   1 +
>  drivers/counter/microchip-tcb-capture.c | 397 ++++++++++++++++++++++++
>  3 files changed, 409 insertions(+)
>  create mode 100644 drivers/counter/microchip-tcb-capture.c
> 
> diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> index c80fa76bb531..2de53ab0dd25 100644
> --- a/drivers/counter/Kconfig
> +++ b/drivers/counter/Kconfig
> @@ -70,4 +70,15 @@ config FTM_QUADDEC
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ftm-quaddec.
>  
> +config MICROCHIP_TCB_CAPTURE
> +	tristate "Microchip Timer Counter Capture driver"
> +	depends on HAS_IOMEM && OF
> +	select REGMAP_MMIO
> +	help
> +	  Select this option to enable the Microchip Timer Counter Block
> +	  capture driver.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called microchip-tcb-capture.
> +
>  endif # COUNTER
> diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> index 55142d1f4c43..0a393f71e481 100644
> --- a/drivers/counter/Makefile
> +++ b/drivers/counter/Makefile
> @@ -10,3 +10,4 @@ obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
>  obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
>  obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
>  obj-$(CONFIG_FTM_QUADDEC)	+= ftm-quaddec.o
> +obj-$(CONFIG_MICROCHIP_TCB_CAPTURE)	+= microchip-tcb-capture.o
> diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
> new file mode 100644
> index 000000000000..f7b7743ddb94
> --- /dev/null
> +++ b/drivers/counter/microchip-tcb-capture.c
> @@ -0,0 +1,397 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/**
> + * Copyright (C) 2020 Microchip
> + *
> + * Author: Kamel Bouhara <kamel.bouhara@bootlin.com>
> + */
> +#include <linux/clk.h>
> +#include <linux/counter.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <soc/at91/atmel_tcb.h>
> +
> +#define ATMEL_TC_CMR_MASK	(ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \
> +				 ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
> +				 ATMEL_TC_LDBSTOP)
> +
> +#define ATMEL_TC_QDEN			BIT(8)
> +#define ATMEL_TC_POSEN			BIT(9)
> +
> +struct mchp_tc_data {
> +	const struct atmel_tcb_config *tc_cfg;
> +	struct counter_device counter;
> +	struct regmap *regmap;
> +	int qdec_mode;
> +	int num_channels;
> +	int channel[2];
> +	bool trig_inverted;
> +};
> +
> +enum mchp_tc_count_function {
> +	MCHP_TC_FUNCTION_INCREASE,
> +	MCHP_TC_FUNCTION_QUADRATURE,
> +};
> +
> +static enum counter_count_function mchp_tc_count_functions[] = {
> +	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
> +	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +};
> +
> +enum mchp_tc_synapse_action {
> +	MCHP_TC_SYNAPSE_ACTION_NONE = 0,
> +	MCHP_TC_SYNAPSE_ACTION_RISING_EDGE,
> +	MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE,
> +	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
> +};
> +
> +static enum counter_synapse_action mchp_tc_synapse_actions[] = {
> +	[MCHP_TC_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
> +	[MCHP_TC_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> +	[MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
> +	[MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
> +};
> +
> +static struct counter_signal mchp_tc_count_signals[] = {
> +	{
> +		.id = 0,
> +		.name = "Channel A",
> +	},
> +	{
> +		.id = 1,
> +		.name = "Channel B",
> +	}
> +};
> +
> +static struct counter_synapse mchp_tc_count_synapses[] = {
> +	{
> +		.actions_list = mchp_tc_synapse_actions,
> +		.num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
> +		.signal = &mchp_tc_count_signals[0]
> +	},
> +	{
> +		.actions_list = mchp_tc_synapse_actions,
> +		.num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
> +		.signal = &mchp_tc_count_signals[1]
> +	}
> +};
> +
> +static int mchp_tc_count_function_get(struct counter_device *counter,
> +				      struct counter_count *count,
> +				      size_t *function)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +
> +	if (priv->qdec_mode)
> +		*function = MCHP_TC_FUNCTION_QUADRATURE;
> +	else
> +		*function = MCHP_TC_FUNCTION_INCREASE;
> +
> +	return 0;
> +}
> +
> +static int mchp_tc_count_function_set(struct counter_device *counter,
> +				      struct counter_count *count,
> +				      size_t function)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +	u32 bmr, cmr;
> +
> +	regmap_read(priv->regmap, ATMEL_TC_BMR, &bmr);
> +	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
> +
> +	/* Set capture mode */
> +	cmr &= ~ATMEL_TC_WAVE;
> +
> +	switch (function) {
> +	case MCHP_TC_FUNCTION_INCREASE:
> +		priv->qdec_mode = 0;
> +		/* Set highest rate based on whether soc has gclk or not */
> +		bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
> +		if (priv->tc_cfg->has_gclk)
> +			cmr |= ATMEL_TC_TIMER_CLOCK2;
> +		else
> +			cmr |= ATMEL_TC_TIMER_CLOCK1;
> +		/* Setup the period capture mode */
> +		cmr |=  ATMEL_TC_CMR_MASK;
> +		cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
> +		break;
> +	case MCHP_TC_FUNCTION_QUADRATURE:
> +		if (!priv->tc_cfg->has_qdec)
> +			return -EINVAL;
> +		/* In QDEC mode settings both channels 0 and 1 are required */
> +		if (priv->num_channels < 2 || priv->channel[0] != 0 ||
> +		    priv->channel[1] != 1) {
> +			pr_err("Invalid channels number or id for quadrature mode\n");
> +			return -EINVAL;
> +		}
> +		priv->qdec_mode = 1;
> +		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
> +		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
> +		break;
> +	}
> +
> +	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
> +	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), cmr);
> +
> +	/* Enable clock and trigger counter */
> +	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CCR),
> +		     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
> +
> +	if (priv->qdec_mode) {
> +		regmap_write(priv->regmap,
> +			     ATMEL_TC_REG(priv->channel[1], CMR), cmr);
> +		regmap_write(priv->regmap,
> +			     ATMEL_TC_REG(priv->channel[1], CCR),
> +			     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mchp_tc_count_signal_read(struct counter_device *counter,
> +				     struct counter_signal *signal,
> +				     enum counter_signal_value *val)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +	bool sigstatus;
> +	u32 sr;
> +
> +	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
> +
> +	if (priv->trig_inverted)
> +		sigstatus = (sr & ATMEL_TC_MTIOB);
> +	else
> +		sigstatus = (sr & ATMEL_TC_MTIOA);
> +
> +	*val = sigstatus ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
> +
> +	return 0;
> +}
> +
> +static int mchp_tc_count_action_get(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    struct counter_synapse *synapse,
> +				    size_t *action)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +	u32 cmr;
> +
> +	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
> +
> +	*action = MCHP_TC_SYNAPSE_ACTION_NONE;
> +
> +	if (cmr & ATMEL_TC_ETRGEDG_NONE)
> +		*action = MCHP_TC_SYNAPSE_ACTION_NONE;
> +	else if (cmr & ATMEL_TC_ETRGEDG_RISING)
> +		*action = MCHP_TC_SYNAPSE_ACTION_RISING_EDGE;
> +	else if (cmr & ATMEL_TC_ETRGEDG_FALLING)
> +		*action = MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE;
> +	else if (cmr & ATMEL_TC_ETRGEDG_BOTH)
> +		*action = MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE;
> +
> +	return 0;
> +}
> +
> +static int mchp_tc_count_action_set(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    struct counter_synapse *synapse,
> +				    size_t action)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +	u32 edge = ATMEL_TC_ETRGEDG_NONE;
> +
> +	/* QDEC mode is rising edge only */
> +	if (priv->qdec_mode)
> +		return -EINVAL;
> +
> +	switch (action) {
> +	case MCHP_TC_SYNAPSE_ACTION_NONE:
> +		edge = ATMEL_TC_ETRGEDG_NONE;
> +		break;
> +	case MCHP_TC_SYNAPSE_ACTION_RISING_EDGE:
> +		edge = ATMEL_TC_ETRGEDG_RISING;
> +		break;
> +	case MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE:
> +		edge = ATMEL_TC_ETRGEDG_FALLING;
> +		break;
> +	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
> +		edge = ATMEL_TC_ETRGEDG_BOTH;
> +		break;
> +	}
> +
> +	return regmap_write_bits(priv->regmap,
> +				ATMEL_TC_REG(priv->channel[0], CMR),
> +				ATMEL_TC_ETRGEDG, edge);
> +}
> +
> +static int mchp_tc_count_read(struct counter_device *counter,
> +			      struct counter_count *count,
> +			      unsigned long *val)
> +{
> +	struct mchp_tc_data *const priv = counter->priv;
> +	u32 cnt;
> +
> +	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CV), &cnt);
> +	*val = cnt;
> +
> +	return 0;
> +}
> +
> +static struct counter_count mchp_tc_counts[] = {
> +	{
> +		.id = 0,
> +		.name = "Timer Counter",
> +		.functions_list = mchp_tc_count_functions,
> +		.num_functions = ARRAY_SIZE(mchp_tc_count_functions),
> +		.synapses = mchp_tc_count_synapses,
> +		.num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
> +	},
> +};
> +
> +static struct counter_ops mchp_tc_ops = {
> +	.signal_read  = mchp_tc_count_signal_read,
> +	.count_read   = mchp_tc_count_read,
> +	.function_get = mchp_tc_count_function_get,
> +	.function_set = mchp_tc_count_function_set,
> +	.action_get   = mchp_tc_count_action_get,
> +	.action_set   = mchp_tc_count_action_set
> +};
> +
> +static const struct atmel_tcb_config tcb_rm9200_config = {
> +		.counter_width = 16,
> +};
> +
> +static const struct atmel_tcb_config tcb_sam9x5_config = {
> +		.counter_width = 32,
> +};
> +
> +static const struct atmel_tcb_config tcb_sama5d2_config = {
> +		.counter_width = 32,
> +		.has_gclk = true,
> +		.has_qdec = true,
> +};
> +
> +static const struct atmel_tcb_config tcb_sama5d3_config = {
> +		.counter_width = 32,
> +		.has_qdec = true,
> +};
> +
> +static const struct of_device_id atmel_tc_of_match[] = {
> +	{ .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
> +	{ .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
> +	{ .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
> +	{ .compatible = "atmel,sama5d3-tcb", .data = &tcb_sama5d3_config, },
> +	{ /* sentinel */ }
> +};
> +
> +static void mchp_tc_clk_remove(void *ptr)
> +{
> +	clk_disable_unprepare((struct clk *)ptr);
> +}
> +
> +static int mchp_tc_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	const struct atmel_tcb_config *tcb_config;
> +	const struct of_device_id *match;
> +	struct mchp_tc_data *priv;
> +	char clk_name[7];
> +	struct regmap *regmap;
> +	struct clk *clk[3];
> +	int channel;
> +	int ret, i;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	match = of_match_node(atmel_tc_of_match, np->parent);
> +	tcb_config = match->data;
> +	if (!tcb_config) {
> +		dev_err(&pdev->dev, "No matching parent node found\n");
> +		return -ENODEV;
> +	}
> +
> +	regmap = syscon_node_to_regmap(np->parent);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
> +
> +	/* max. channels number is 2 when in QDEC mode */
> +	priv->num_channels = of_property_count_u32_elems(np, "reg");
> +	if (priv->num_channels < 0) {
> +		dev_err(&pdev->dev, "Invalid or missing channel\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Register channels and initialize clocks */
> +	for (i = 0; i < priv->num_channels; i++) {
> +		ret = of_property_read_u32_index(np, "reg", i, &channel);
> +		if (ret < 0 || channel > 2)
> +			return -ENODEV;
> +
> +		priv->channel[i] = channel;
> +
> +		snprintf(clk_name, sizeof(clk_name), "t%d_clk", channel);
> +
> +		clk[i] = of_clk_get_by_name(np->parent, clk_name);
> +		if (IS_ERR(clk[i])) {
> +			/* Fallback to t0_clk */
> +			clk[i] = of_clk_get_by_name(np->parent, "t0_clk");
> +			if (IS_ERR(clk[i]))
> +				return PTR_ERR(clk[i]);
> +		}
> +
> +		ret = clk_prepare_enable(clk[i]);
> +		if (ret)
> +			return ret;
> +
> +		ret = devm_add_action_or_reset(&pdev->dev,
> +					       mchp_tc_clk_remove,
> +					       clk[i]);
> +		if (ret)
> +			return ret;
> +
> +		dev_dbg(&pdev->dev,
> +			"Initialized capture mode on channel %d\n",
> +			channel);
> +	}
> +
> +	priv->tc_cfg = tcb_config;
> +	priv->regmap = regmap;
> +	priv->counter.name = dev_name(&pdev->dev);
> +	priv->counter.parent = &pdev->dev;
> +	priv->counter.ops = &mchp_tc_ops;
> +	priv->counter.num_counts = ARRAY_SIZE(mchp_tc_counts);
> +	priv->counter.counts = mchp_tc_counts;
> +	priv->counter.num_signals = ARRAY_SIZE(mchp_tc_count_signals);
> +	priv->counter.signals = mchp_tc_count_signals;
> +	priv->counter.priv = priv;
> +
> +	return devm_counter_register(&pdev->dev, &priv->counter);
> +}
> +
> +static const struct of_device_id mchp_tc_dt_ids[] = {
> +	{ .compatible = "microchip,tcb-capture", },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, mchp_tc_dt_ids);
> +
> +static struct platform_driver mchp_tc_driver = {
> +	.probe = mchp_tc_probe,
> +	.driver = {
> +		.name = "microchip-tcb-capture",
> +		.of_match_table = mchp_tc_dt_ids,
> +	},
> +};
> +module_platform_driver(mchp_tc_driver);
> +
> +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
> +MODULE_DESCRIPTION("Microchip TCB Capture driver");
> +MODULE_LICENSE("GPL v2");
William Breathitt Gray May 24, 2020, 3:35 p.m. UTC | #2
On Sun, May 24, 2020 at 04:16:24PM +0100, Jonathan Cameron wrote:
> On Tue, 19 May 2020 10:37:16 +0200
> Kamel Bouhara <kamel.bouhara@bootlin.com> wrote:
> 
> > This drivers allows to use the capture mode of the Timer Counter Block
> > hardware block available in Microchip SoCs through the counter subsystem.
> > 
> > Two functions of the counter are supported for the moment: period
> > capture and quadrature decoder. The latter is only supported by the
> > SAMA5 series of SoCs.
> > 
> > For the period capture mode a basic setup has been chosen that will
> > reset the counter each time the period is actually reached. Of course
> > the device offers much more possibilities.
> > 
> > For quadrature mode, both channel 0 and 1 must be configured even if we
> > only capture the position (no revolution/rotation).
> > 
> > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> Looks good to me.  After reviews from William, DT and maybe
> something from SoC side if intent is I'm taking this.
> 
> Jonathan

I'll defer to the DT maintainers for the dt-binding changes. Regarding
this counter driver, I believe there have been no changes since I
signed-off for it in the v3 patchset thread. If that's true, I haven't
changed my mind -- I'm still statisfied with this particular version and
have no objections if it's merged. ;-)

William Breathitt Gray