diff mbox series

[v3,5/9] i2c: at91: add support for digital filtering

Message ID 1562678049-17581-6-git-send-email-eugen.hristev@microchip.com
State Superseded
Headers show
Series i2c: add support for filters | expand

Commit Message

Eugen Hristev July 9, 2019, 1:19 p.m. UTC 
From: Eugen Hristev <eugen.hristev@microchip.com>

Add new platform data support for digital filtering for i2c.
The sama5d4, sama5d2 and sam9x60 support this feature.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
 drivers/i2c/busses/i2c-at91-core.c   | 9 +++++++++
 drivers/i2c/busses/i2c-at91-master.c | 9 +++++++++
 drivers/i2c/busses/i2c-at91.h        | 5 +++++
 3 files changed, 23 insertions(+)

Comments

Wolfram Sang Aug. 31, 2019, 12:13 p.m. UTC | #1 
> diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
> index a663a7a..62610af 100644
> --- a/drivers/i2c/busses/i2c-at91-core.c
> +++ b/drivers/i2c/busses/i2c-at91-core.c
> @@ -68,6 +68,7 @@ static struct at91_twi_pdata at91rm9200_config = {
>  	.has_unre_flag = true,
>  	.has_alt_cmd = false,
>  	.has_hold_field = false,
> +	.has_dig_filtr = false,

Hmm, 'false' is the default. Maybe not for this series, but it might
make sense to clean up the driver afterwards removing the superfluous
'false'. The precedence will make adding new properties much simpler.


> +	dev->enable_dig_filt = of_property_read_bool(pdev->dev.of_node,
> +						     "i2c-dig-filter");
> +

What do you think of the idea to introduce 'flags' to struct i2c_timings
and parse the bindings in the core, too? Then you'd have sth like:

	if (t->flags & I2C_TIMINGS_ANALOG_FILTER)

Would that be useful for you?
Wolfram Sang Aug. 31, 2019, 12:17 p.m. UTC | #2 
> > +	dev->enable_dig_filt = of_property_read_bool(pdev->dev.of_node,
> > +						     "i2c-dig-filter");
> > +
> 
> What do you think of the idea to introduce 'flags' to struct i2c_timings
> and parse the bindings in the core, too? Then you'd have sth like:
> 
> 	if (t->flags & I2C_TIMINGS_ANALOG_FILTER)
> 
> Would that be useful for you?

Forgot to say, we can also implement this incrementally to make sure
your patches land in 5.4 in case you are currently busy with sth else.
Eugen Hristev Sept. 2, 2019, 8:54 a.m. UTC | #3 
On 31.08.2019 15:17, Wolfram Sang wrote:
> 
>>> +	dev->enable_dig_filt = of_property_read_bool(pdev->dev.of_node,
>>> +						     "i2c-dig-filter");
>>> +
>>
>> What do you think of the idea to introduce 'flags' to struct i2c_timings
>> and parse the bindings in the core, too? Then you'd have sth like:
>>
>> 	if (t->flags & I2C_TIMINGS_ANALOG_FILTER)
>>
>> Would that be useful for you?
> 
> Forgot to say, we can also implement this incrementally to make sure
> your patches land in 5.4 in case you are currently busy with sth else.
> 

Hi Wolfram,

Your idea looks good but I would prefer to have it as a separate 
enhancement patch, after this series gets in.
As things are now, this series/patches do just the filtering part. We 
can then move all the optional 'flags' as another change.
So yes, we can do this incrementally.

Thanks !
Eugen

> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index a663a7a..62610af 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -68,6 +68,7 @@  static struct at91_twi_pdata at91rm9200_config = {
 	.has_unre_flag = true,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static struct at91_twi_pdata at91sam9261_config = {
@@ -76,6 +77,7 @@  static struct at91_twi_pdata at91sam9261_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static struct at91_twi_pdata at91sam9260_config = {
@@ -84,6 +86,7 @@  static struct at91_twi_pdata at91sam9260_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static struct at91_twi_pdata at91sam9g20_config = {
@@ -92,6 +95,7 @@  static struct at91_twi_pdata at91sam9g20_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static struct at91_twi_pdata at91sam9g10_config = {
@@ -100,6 +104,7 @@  static struct at91_twi_pdata at91sam9g10_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static const struct platform_device_id at91_twi_devtypes[] = {
@@ -130,6 +135,7 @@  static struct at91_twi_pdata at91sam9x5_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_dig_filtr = false,
 };
 
 static struct at91_twi_pdata sama5d4_config = {
@@ -138,6 +144,7 @@  static struct at91_twi_pdata sama5d4_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = true,
+	.has_dig_filtr = true,
 };
 
 static struct at91_twi_pdata sama5d2_config = {
@@ -146,6 +153,7 @@  static struct at91_twi_pdata sama5d2_config = {
 	.has_unre_flag = true,
 	.has_alt_cmd = true,
 	.has_hold_field = true,
+	.has_dig_filtr = true,
 };
 
 static struct at91_twi_pdata sam9x60_config = {
@@ -154,6 +162,7 @@  static struct at91_twi_pdata sam9x60_config = {
 	.has_unre_flag = true,
 	.has_alt_cmd = true,
 	.has_hold_field = true,
+	.has_dig_filtr = true,
 };
 
 static const struct of_device_id atmel_twi_dt_ids[] = {
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index e87232f..099161a 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -31,12 +31,18 @@ 
 
 void at91_init_twi_bus_master(struct at91_twi_dev *dev)
 {
+	struct at91_twi_pdata *pdata = dev->pdata;
+
 	/* FIFO should be enabled immediately after the software reset */
 	if (dev->fifo_size)
 		at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
 	at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
 	at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
 	at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
+
+	/* enable digital filter */
+	if (pdata->has_dig_filtr && dev->enable_dig_filt)
+		at91_twi_write(dev, AT91_TWI_FILTR, AT91_TWI_FILTR_FILT);
 }
 
 /*
@@ -792,6 +798,9 @@  int at91_twi_probe_master(struct platform_device *pdev,
 		dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
 	}
 
+	dev->enable_dig_filt = of_property_read_bool(pdev->dev.of_node,
+						     "i2c-dig-filter");
+
 	at91_calc_twi_clock(dev);
 
 	dev->adapter.algo = &at91_twi_algorithm;
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 499b506..c75447e 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -84,6 +84,9 @@ 
 #define	AT91_TWI_ACR_DATAL(len)	((len) & 0xff)
 #define	AT91_TWI_ACR_DIR	BIT(8)
 
+#define AT91_TWI_FILTR		0x0044
+#define AT91_TWI_FILTR_FILT	BIT(0)
+
 #define	AT91_TWI_FMR		0x0050	/* FIFO Mode Register */
 #define	AT91_TWI_FMR_TXRDYM(mode)	(((mode) & 0x3) << 0)
 #define	AT91_TWI_FMR_TXRDYM_MASK	(0x3 << 0)
@@ -108,6 +111,7 @@  struct at91_twi_pdata {
 	bool has_unre_flag;
 	bool has_alt_cmd;
 	bool has_hold_field;
+	bool has_dig_filtr;
 	struct at_dma_slave dma_slave;
 };
 
@@ -145,6 +149,7 @@  struct at91_twi_dev {
 	unsigned smr;
 	struct i2c_client *slave;
 #endif
+	bool enable_dig_filt;
 };
 
 unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);