[cip-dev] [PATCH] spi: pxa2xx: Add support for GPIO descriptor chip selects

[cip-dev] [PATCH] spi: pxa2xx: Add support for GPIO descriptor chip selects

[Jan Kiszka]

From: Mika Westerberg <mika.westerberg@linux.intel.com>

commit 99f499cd650405bbe6a9b5386d4b11ee81514fb7 upstream.

The driver uses custom chip_info coming from platform data for chip selects
implemented as GPIOs. If the system lacks board files setting up the
platform data, it is not possible to use GPIOs as chip selects.

This adds support for GPIO descriptors so that regardless of the underlying
firmware interface (DT, ACPI or platform data) the driver can request GPIOs
used as chip selects and configure them accordingly.

The custom chip_info GPIO support is still left there to make sure the
existing systems keep working as expected.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

...and another one I missed as dependency for our IOT2000.

 drivers/spi/spi-pxa2xx.c | 57 +++++++++++++++++++++++++++++++++++++++++++++---
 drivers/spi/spi-pxa2xx.h |  3 +++
 2 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 3cac73e4c3e4..21339ca204d9 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -1122,9 +1122,26 @@ static int pxa2xx_spi_unprepare_transfer(struct spi_master *master)
 static int setup_cs(struct spi_device *spi, struct chip_data *chip,
 		    struct pxa2xx_spi_chip *chip_info)
 {
+	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
 	int err = 0;
 
-	if (chip == NULL || chip_info == NULL)
+	if (chip == NULL)
+		return 0;
+
+	if (drv_data->cs_gpiods) {
+		struct gpio_desc *gpiod;
+
+		gpiod = drv_data->cs_gpiods[spi->chip_select];
+		if (gpiod) {
+			chip->gpio_cs = desc_to_gpio(gpiod);
+			chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
+			gpiod_set_value(gpiod, chip->gpio_cs_inverted);
+		}
+
+		return 0;
+	}
+
+	if (chip_info == NULL)
 		return 0;
 
 	/* NOTE: setup() can be called multiple times, possibly with
@@ -1305,7 +1322,8 @@ static void cleanup(struct spi_device *spi)
 	if (!chip)
 		return;
 
-	if (drv_data->ssp_type != CE4100_SSP && gpio_is_valid(chip->gpio_cs))
+	if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
+	    gpio_is_valid(chip->gpio_cs))
 		gpio_free(chip->gpio_cs);
 
 	kfree(chip);
@@ -1453,7 +1471,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 	struct driver_data *drv_data;
 	struct ssp_device *ssp;
 	const struct lpss_config *config;
-	int status;
+	int status, count;
 	u32 tmp;
 
 	platform_info = dev_get_platdata(dev);
@@ -1590,6 +1608,39 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 	}
 	master->num_chipselect = platform_info->num_chipselect;
 
+	count = gpiod_count(&pdev->dev, "cs");
+	if (count > 0) {
+		int i;
+
+		master->num_chipselect = max_t(int, count,
+			master->num_chipselect);
+
+		drv_data->cs_gpiods = devm_kcalloc(&pdev->dev,
+			master->num_chipselect, sizeof(struct gpio_desc *),
+			GFP_KERNEL);
+		if (!drv_data->cs_gpiods) {
+			status = -ENOMEM;
+			goto out_error_clock_enabled;
+		}
+
+		for (i = 0; i < master->num_chipselect; i++) {
+			struct gpio_desc *gpiod;
+
+			gpiod = devm_gpiod_get_index(dev, "cs", i,
+						     GPIOD_OUT_HIGH);
+			if (IS_ERR(gpiod)) {
+				/* Means use native chip select */
+				if (PTR_ERR(gpiod) == -ENOENT)
+					continue;
+
+				status = (int)PTR_ERR(gpiod);
+				goto out_error_clock_enabled;
+			} else {
+				drv_data->cs_gpiods[i] = gpiod;
+			}
+		}
+	}
+
 	tasklet_init(&drv_data->pump_transfers, pump_transfers,
 		     (unsigned long)drv_data);
 
diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
index 58efa98313aa..1320538f8623 100644
--- a/drivers/spi/spi-pxa2xx.h
+++ b/drivers/spi/spi-pxa2xx.h
@@ -80,6 +80,9 @@ struct driver_data {
 	void (*cs_control)(u32 command);
 
 	void __iomem *lpss_base;
+
+	/* GPIOs for chip selects */
+	struct gpio_desc **cs_gpiods;
 };
 
 struct chip_data {

[cip-dev] [PATCH] spi: pxa2xx: Add support for GPIO descriptor chip selects

[Ben Hutchings]

On Fri, 2017-11-17 at 21:45 +0100, Jan Kiszka wrote:
> From: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> commit 99f499cd650405bbe6a9b5386d4b11ee81514fb7 upstream.
> 
> The driver uses custom chip_info coming from platform data for chip selects
> implemented as GPIOs. If the system lacks board files setting up the
> platform data, it is not possible to use GPIOs as chip selects.
> 
> This adds support for GPIO descriptors so that regardless of the underlying
> firmware interface (DT, ACPI or platform data) the driver can request GPIOs
> used as chip selects and configure them accordingly.
> 
> The custom chip_info GPIO support is still left there to make sure the
> existing systems keep working as expected.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> 
> ...and another one I missed as dependency for our IOT2000.
> 
> ?drivers/spi/spi-pxa2xx.c | 57 +++++++++++++++++++++++++++++++++++++++++++++---
> ?drivers/spi/spi-pxa2xx.h |??3 +++
> ?2 files changed, 57 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> index 3cac73e4c3e4..21339ca204d9 100644
> --- a/drivers/spi/spi-pxa2xx.c
> +++ b/drivers/spi/spi-pxa2xx.c
> @@ -1122,9 +1122,26 @@ static int pxa2xx_spi_unprepare_transfer(struct spi_master *master)
> ?static int setup_cs(struct spi_device *spi, struct chip_data *chip,
> ?		????struct pxa2xx_spi_chip *chip_info)
> ?{
> +	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
> ?	int err = 0;
> ?
> -	if (chip == NULL || chip_info == NULL)
> +	if (chip == NULL)
> +		return 0;
> +
> +	if (drv_data->cs_gpiods) {
> +		struct gpio_desc *gpiod;
> +
> +		gpiod = drv_data->cs_gpiods[spi->chip_select];
> +		if (gpiod) {
> +			chip->gpio_cs = desc_to_gpio(gpiod);
> +			chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;

This assigns a value of 0 or 4 to chip->gpio_cs_inverted, when it
surely should be 0 or 1.  With the current gpiolib implementation this
appears to work anyway, but I wouldn't want to assume that's true.

[...]
> @@ -1305,7 +1322,8 @@ static void cleanup(struct spi_device *spi)
> ????????if (!chip)
> ????????????????return;
> ?
> -???????if (drv_data->ssp_type != CE4100_SSP && gpio_is_valid(chip->gpio_cs))
> +???????if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
> +???????????gpio_is_valid(chip->gpio_cs))
> ????????????????gpio_free(chip->gpio_cs);
[...]

This is really weird; I think the driver should consistently use
managed or unmanaged allocation of GPIOs.

But I don't think these are blockers for backporting, so I've applied
this anyway.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

[cip-dev] [PATCH] spi: pxa2xx: Add support for GPIO descriptor chip selects

[Jan Kiszka]

On 2017-11-22 17:53, Ben Hutchings wrote:
> On Fri, 2017-11-17 at 21:45 +0100, Jan Kiszka wrote:
>> From: Mika Westerberg <mika.westerberg@linux.intel.com>
>>
>> commit 99f499cd650405bbe6a9b5386d4b11ee81514fb7 upstream.
>>
>> The driver uses custom chip_info coming from platform data for chip selects
>> implemented as GPIOs. If the system lacks board files setting up the
>> platform data, it is not possible to use GPIOs as chip selects.
>>
>> This adds support for GPIO descriptors so that regardless of the underlying
>> firmware interface (DT, ACPI or platform data) the driver can request GPIOs
>> used as chip selects and configure them accordingly.
>>
>> The custom chip_info GPIO support is still left there to make sure the
>> existing systems keep working as expected.
>>
>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>> Signed-off-by: Mark Brown <broonie@kernel.org>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>
>> ...and another one I missed as dependency for our IOT2000.
>>
>> ?drivers/spi/spi-pxa2xx.c | 57 +++++++++++++++++++++++++++++++++++++++++++++---
>> ?drivers/spi/spi-pxa2xx.h |??3 +++
>> ?2 files changed, 57 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
>> index 3cac73e4c3e4..21339ca204d9 100644
>> --- a/drivers/spi/spi-pxa2xx.c
>> +++ b/drivers/spi/spi-pxa2xx.c
>> @@ -1122,9 +1122,26 @@ static int pxa2xx_spi_unprepare_transfer(struct spi_master *master)
>> ?static int setup_cs(struct spi_device *spi, struct chip_data *chip,
>> ?		????struct pxa2xx_spi_chip *chip_info)
>> ?{
>> +	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
>> ?	int err = 0;
>> ?
>> -	if (chip == NULL || chip_info == NULL)
>> +	if (chip == NULL)
>> +		return 0;
>> +
>> +	if (drv_data->cs_gpiods) {
>> +		struct gpio_desc *gpiod;
>> +
>> +		gpiod = drv_data->cs_gpiods[spi->chip_select];
>> +		if (gpiod) {
>> +			chip->gpio_cs = desc_to_gpio(gpiod);
>> +			chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
> 
> This assigns a value of 0 or 4 to chip->gpio_cs_inverted, when it
> surely should be 0 or 1.  With the current gpiolib implementation this
> appears to work anyway, but I wouldn't want to assume that's true.

Indeed.

> 
> [...]
>> @@ -1305,7 +1322,8 @@ static void cleanup(struct spi_device *spi)
>> ????????if (!chip)
>> ????????????????return;
>> ?
>> -???????if (drv_data->ssp_type != CE4100_SSP && gpio_is_valid(chip->gpio_cs))
>> +???????if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
>> +???????????gpio_is_valid(chip->gpio_cs))
>> ????????????????gpio_free(chip->gpio_cs);
> [...]
> 
> This is really weird; I think the driver should consistently use
> managed or unmanaged allocation of GPIOs.

Yes, there is another patch in upstream to improve this:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c18d925fca20d33c3d04e5002a883f62d699543e

> 
> But I don't think these are blockers for backporting, so I've applied
> this anyway.
> 

Thanks (also for cross-checking),
Jan

[cip-dev] [PATCH] spi: pxa2xx: Add support for GPIO descriptor chip selects

[Ben Hutchings]

On Wed, 2017-11-22 at 18:01 +0100, Jan Kiszka wrote:
> On 2017-11-22 17:53, Ben Hutchings wrote:
> > On Fri, 2017-11-17 at 21:45 +0100, Jan Kiszka wrote:
> > > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > 
> > > commit 99f499cd650405bbe6a9b5386d4b11ee81514fb7 upstream.
> > > 
> > > The driver uses custom chip_info coming from platform data for chip selects
> > > implemented as GPIOs. If the system lacks board files setting up the
> > > platform data, it is not possible to use GPIOs as chip selects.
> > > 
> > > This adds support for GPIO descriptors so that regardless of the underlying
> > > firmware interface (DT, ACPI or platform data) the driver can request GPIOs
> > > used as chip selects and configure them accordingly.
> > > 
> > > The custom chip_info GPIO support is still left there to make sure the
> > > existing systems keep working as expected.
> > > 
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > Signed-off-by: Mark Brown <broonie@kernel.org>
> > > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> > > ---
> > > 
> > > ...and another one I missed as dependency for our IOT2000.
> > > 
> > > ?drivers/spi/spi-pxa2xx.c | 57 +++++++++++++++++++++++++++++++++++++++++++++---
> > > ?drivers/spi/spi-pxa2xx.h |??3 +++
> > > ?2 files changed, 57 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> > > index 3cac73e4c3e4..21339ca204d9 100644
> > > --- a/drivers/spi/spi-pxa2xx.c
> > > +++ b/drivers/spi/spi-pxa2xx.c
> > > @@ -1122,9 +1122,26 @@ static int pxa2xx_spi_unprepare_transfer(struct spi_master *master)
> > > ?static int setup_cs(struct spi_device *spi, struct chip_data *chip,
> > > > > > ?		????struct pxa2xx_spi_chip *chip_info)
> > > ?{
> > > > > > +	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
> > > > > > ?	int err = 0;
> > > ?
> > > > > > -	if (chip == NULL || chip_info == NULL)
> > > > > > +	if (chip == NULL)
> > > > > > +		return 0;
> > > +
> > > +	if (drv_data->cs_gpiods) {
> > > +		struct gpio_desc *gpiod;
> > > +
> > > +		gpiod = drv_data->cs_gpiods[spi->chip_select];
> > > +		if (gpiod) {
> > > +			chip->gpio_cs = desc_to_gpio(gpiod);
> > > +			chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
> > 
> > This assigns a value of 0 or 4 to chip->gpio_cs_inverted, when it
> > surely should be 0 or 1.??With the current gpiolib implementation this
> > appears to work anyway, but I wouldn't want to assume that's true.
> 
> Indeed.
> 
> > 
> > [...]
> > > @@ -1305,7 +1322,8 @@ static void cleanup(struct spi_device *spi)
> > > ????????if (!chip)
> > > ????????????????return;
> > > ?
> > > -???????if (drv_data->ssp_type != CE4100_SSP && gpio_is_valid(chip->gpio_cs))
> > > +???????if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
> > > +???????????gpio_is_valid(chip->gpio_cs))
> > > ????????????????gpio_free(chip->gpio_cs);
> > 
> > [...]
> > 
> > This is really weird; I think the driver should consistently use
> > managed or unmanaged allocation of GPIOs.
> 
> Yes, there is another patch in upstream to improve this:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c18d925fca20d33c3d04e5002a883f62d699543e

I'm talking about use of devm_gpio_get() (with automatic free) vs
gpio_request()/gpio_free().

Ben.

> > 
> > But I don't think these are blockers for backporting, so I've applied
> > this anyway.
> > 
> 
> Thanks (also for cross-checking),
> Jan
> 
-- 
Ben Hutchings
Software Developer, Codethink Ltd.