[PATCH] pca953x: Add optional reset gpio control

[PATCH] pca953x: Add optional reset gpio control

[Steve Longerbeam]

Add optional reset-gpios pin control. If present, de-assert the
specified reset gpio pin to bring the chip out of reset.


Steve Longerbeam (1):
  gpio: pca953x: Add optional reset gpio control

 Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
 drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
 2 files changed, 15 insertions(+)

-- 
2.7.4

[PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

Add optional reset-gpios pin control. If present, de-assert the
specified reset gpio pin to bring the chip out of reset.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: linux-gpio@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
 drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
index 08dd15f..da54f4c 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
@@ -29,6 +29,10 @@ Required properties:
 	onsemi,pca9654
 	exar,xra1202
 
+Optional properties:
+ - reset-gpios: GPIO specification for the RESET input
+
+
 Example:
 
 
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index d5d72d8..ca2ddea 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -22,6 +22,7 @@
 #include <linux/of_platform.h>
 #include <linux/acpi.h>
 #include <linux/regulator/consumer.h>
+#include <linux/gpio/consumer.h>
 
 #define PCA953X_INPUT		0
 #define PCA953X_OUTPUT		1
@@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
 		invert = pdata->invert;
 		chip->names = pdata->names;
 	} else {
+		struct gpio_desc *reset_gpio;
+
 		chip->gpio_start = -1;
 		irq_base = 0;
+
+		/* see if we need to de-assert a reset pin */
+		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						     GPIOD_OUT_LOW);
+		if (IS_ERR(reset_gpio)) {
+			dev_err(&client->dev, "request for reset pin failed\n");
+			return PTR_ERR(reset_gpio);
+		}
 	}
 
 	chip->client = client;
-- 
2.7.4

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Andy Shevchenko]

On Mon, Jan 2, 2017 at 11:07 PM, Steve Longerbeam <slongerbeam@gmail.com> wrote:
> Add optional reset-gpios pin control. If present, de-assert the
> specified reset gpio pin to bring the chip out of reset.

> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -22,6 +22,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/acpi.h>
>  #include <linux/regulator/consumer.h>

> +#include <linux/gpio/consumer.h>

Please, try to put it somehow alphabetically ordered (yes, I see it's
not in general, but try to squeeze it into longest part which is
ordered).

>
>  #define PCA953X_INPUT          0
>  #define PCA953X_OUTPUT         1
> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>                 invert = pdata->invert;
>                 chip->names = pdata->names;
>         } else {
> +               struct gpio_desc *reset_gpio;
> +
>                 chip->gpio_start = -1;
>                 irq_base = 0;
> +
> +               /* see if we need to de-assert a reset pin */

see -> See

> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> +                                                    GPIOD_OUT_LOW);

Shouldn't be _optional_exclusive?
See this recent discussion https://patchwork.ozlabs.org/patch/706002/

> +               if (IS_ERR(reset_gpio)) {
> +                       dev_err(&client->dev, "request for reset pin failed\n");
> +                       return PTR_ERR(reset_gpio);
> +               }
>         }

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Vladimir Zapolskiy]

On 01/04/2017 01:37 AM, Andy Shevchenko wrote:
> On Mon, Jan 2, 2017 at 11:07 PM, Steve Longerbeam <slongerbeam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Add optional reset-gpios pin control. If present, de-assert the
>> specified reset gpio pin to bring the chip out of reset.
> 
>> --- a/drivers/gpio/gpio-pca953x.c
>> +++ b/drivers/gpio/gpio-pca953x.c
>> @@ -22,6 +22,7 @@
>>  #include <linux/of_platform.h>
>>  #include <linux/acpi.h>
>>  #include <linux/regulator/consumer.h>
> 
>> +#include <linux/gpio/consumer.h>
> 
> Please, try to put it somehow alphabetically ordered (yes, I see it's
> not in general, but try to squeeze it into longest part which is
> ordered).
> 
>>
>>  #define PCA953X_INPUT          0
>>  #define PCA953X_OUTPUT         1
>> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>>                 invert = pdata->invert;
>>                 chip->names = pdata->names;
>>         } else {
>> +               struct gpio_desc *reset_gpio;
>> +
>>                 chip->gpio_start = -1;
>>                 irq_base = 0;
>> +
>> +               /* see if we need to de-assert a reset pin */
> 
> see -> See
> 
>> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
>> +                                                    GPIOD_OUT_LOW);
> 
> Shouldn't be _optional_exclusive?
> See this recent discussion https://patchwork.ozlabs.org/patch/706002/

There is no devm_gpiod_get_optional_exclusive(), probably you confuse
the function with devm_reset_control_get_optional_exclusive().

>> +               if (IS_ERR(reset_gpio)) {
>> +                       dev_err(&client->dev, "request for reset pin failed\n");
>> +                       return PTR_ERR(reset_gpio);
>> +               }
>>         }
> 

--
With best wishes,
Vladimir
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Andy Shevchenko]

On Wed, Jan 4, 2017 at 12:20 PM, Vladimir Zapolskiy
<vladimir_zapolskiy-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org> wrote:
> On 01/04/2017 01:37 AM, Andy Shevchenko wrote:
>> On Mon, Jan 2, 2017 at 11:07 PM, Steve Longerbeam <slongerbeam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>> Add optional reset-gpios pin control. If present, de-assert the
>>> specified reset gpio pin to bring the chip out of reset.
>>
>>> --- a/drivers/gpio/gpio-pca953x.c
>>> +++ b/drivers/gpio/gpio-pca953x.c
>>> @@ -22,6 +22,7 @@
>>>  #include <linux/of_platform.h>
>>>  #include <linux/acpi.h>
>>>  #include <linux/regulator/consumer.h>
>>
>>> +#include <linux/gpio/consumer.h>
>>
>> Please, try to put it somehow alphabetically ordered (yes, I see it's
>> not in general, but try to squeeze it into longest part which is
>> ordered).
>>
>>>
>>>  #define PCA953X_INPUT          0
>>>  #define PCA953X_OUTPUT         1
>>> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>>>                 invert = pdata->invert;
>>>                 chip->names = pdata->names;
>>>         } else {
>>> +               struct gpio_desc *reset_gpio;
>>> +
>>>                 chip->gpio_start = -1;
>>>                 irq_base = 0;
>>> +
>>> +               /* see if we need to de-assert a reset pin */
>>
>> see -> See
>>
>>> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
>>> +                                                    GPIOD_OUT_LOW);
>>
>> Shouldn't be _optional_exclusive?
>> See this recent discussion https://patchwork.ozlabs.org/patch/706002/
>
> There is no devm_gpiod_get_optional_exclusive(), probably you confuse
> the function with devm_reset_control_get_optional_exclusive().

Perhaps it's time to add
drivers/reset/reset-gpio.c ?

>
>>> +               if (IS_ERR(reset_gpio)) {
>>> +                       dev_err(&client->dev, "request for reset pin failed\n");
>>> +                       return PTR_ERR(reset_gpio);
>>> +               }
>>>         }
>>
>
> --
> With best wishes,
> Vladimir



-- 
With Best Regards,
Andy Shevchenko
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

On 01/04/2017 02:31 AM, Andy Shevchenko wrote:
>
>>>> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
>>>> +                                                    GPIOD_OUT_LOW);
>>> Shouldn't be _optional_exclusive?
>>> See this recent discussion https://patchwork.ozlabs.org/patch/706002/
>> There is no devm_gpiod_get_optional_exclusive(), probably you confuse
>> the function with devm_reset_control_get_optional_exclusive().
> Perhaps it's time to add
> drivers/reset/reset-gpio.c ?

Yeah, looks like a GPIO based reset controller driver would need to be
implemented in order to go this route. The max7310 nodes in
imx6qdl-sabreauto.dtsi could then refer to that reset controller by the
'resets' phandle.

There are many many devices that would benefit from a GPIO reset
controller, I count 143 nodes under arch/arm/boot/dts that specify a
'reset-gpios' property.

But I don't have the time to write such a driver. So I would propose just
keeping the devm_gpiod_get_optional() call here. When such a gpio reset
controller is written, the work can begin to convert all the gpio reset 
users
to make use of it.

Steve

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

On 01/03/2017 03:37 PM, Andy Shevchenko wrote:
> On Mon, Jan 2, 2017 at 11:07 PM, Steve Longerbeam <slongerbeam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Add optional reset-gpios pin control. If present, de-assert the
>> specified reset gpio pin to bring the chip out of reset.
>> --- a/drivers/gpio/gpio-pca953x.c
>> +++ b/drivers/gpio/gpio-pca953x.c
>> @@ -22,6 +22,7 @@
>>   #include <linux/of_platform.h>
>>   #include <linux/acpi.h>
>>   #include <linux/regulator/consumer.h>
>> +#include <linux/gpio/consumer.h>
> Please, try to put it somehow alphabetically ordered (yes, I see it's
> not in general, but try to squeeze it into longest part which is
> ordered).

done.

>
>>   #define PCA953X_INPUT          0
>>   #define PCA953X_OUTPUT         1
>> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>>                  invert = pdata->invert;
>>                  chip->names = pdata->names;
>>          } else {
>> +               struct gpio_desc *reset_gpio;
>> +
>>                  chip->gpio_start = -1;
>>                  irq_base = 0;
>> +
>> +               /* see if we need to de-assert a reset pin */
> see -> See

done.


Steve

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Vladimir Zapolskiy]

Hi Steve,

On 01/02/2017 11:07 PM, Steve Longerbeam wrote:
> Add optional reset-gpios pin control. If present, de-assert the
> specified reset gpio pin to bring the chip out of reset.
> 
> Signed-off-by: Steve Longerbeam <steve_longerbeam-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>
> Cc: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> Cc: Alexandre Courbot <gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Cc: linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
>  drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> index 08dd15f..da54f4c 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> @@ -29,6 +29,10 @@ Required properties:
>  	onsemi,pca9654
>  	exar,xra1202
>  
> +Optional properties:
> + - reset-gpios: GPIO specification for the RESET input
> +
> +

Drop the surplus empty line above.

>  Example:
>  
>  
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index d5d72d8..ca2ddea 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -22,6 +22,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/acpi.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/gpio/consumer.h>
>  
>  #define PCA953X_INPUT		0
>  #define PCA953X_OUTPUT		1
> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>  		invert = pdata->invert;
>  		chip->names = pdata->names;
>  	} else {
> +		struct gpio_desc *reset_gpio;
> +
>  		chip->gpio_start = -1;
>  		irq_base = 0;
> +
> +		/* see if we need to de-assert a reset pin */
> +		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> +						     GPIOD_OUT_LOW);
> +		if (IS_ERR(reset_gpio)) {
> +			dev_err(&client->dev, "request for reset pin failed\n");

I'm not confident that the error message is wanted here, you may consider either
to remove it or at least print it out if (PTR_ERR(reset_gpio) != -EPROBE_DEFER).

> +			return PTR_ERR(reset_gpio);
> +		}
>  	}
>  
>  	chip->client = client;
> 

Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>

--
With best wishes,
Vladimir
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

On 01/04/2017 02:25 AM, Vladimir Zapolskiy wrote:
> Hi Steve,
>
> On 01/02/2017 11:07 PM, Steve Longerbeam wrote:
>> Add optional reset-gpios pin control. If present, de-assert the
>> specified reset gpio pin to bring the chip out of reset.
>>
>> Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
>> Cc: Linus Walleij <linus.walleij@linaro.org>
>> Cc: Alexandre Courbot <gnurou@gmail.com>
>> Cc: linux-gpio@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>>   Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
>>   drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
>>   2 files changed, 15 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> index 08dd15f..da54f4c 100644
>> --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> @@ -29,6 +29,10 @@ Required properties:
>>   	onsemi,pca9654
>>   	exar,xra1202
>>   
>> +Optional properties:
>> + - reset-gpios: GPIO specification for the RESET input
>> +
>> +
> Drop the surplus empty line above.

done.

>
>>   Example:
>>   
>>   
>> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
>> index d5d72d8..ca2ddea 100644
>> --- a/drivers/gpio/gpio-pca953x.c
>> +++ b/drivers/gpio/gpio-pca953x.c
>> @@ -22,6 +22,7 @@
>>   #include <linux/of_platform.h>
>>   #include <linux/acpi.h>
>>   #include <linux/regulator/consumer.h>
>> +#include <linux/gpio/consumer.h>
>>   
>>   #define PCA953X_INPUT		0
>>   #define PCA953X_OUTPUT		1
>> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>>   		invert = pdata->invert;
>>   		chip->names = pdata->names;
>>   	} else {
>> +		struct gpio_desc *reset_gpio;
>> +
>>   		chip->gpio_start = -1;
>>   		irq_base = 0;
>> +
>> +		/* see if we need to de-assert a reset pin */
>> +		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
>> +						     GPIOD_OUT_LOW);
>> +		if (IS_ERR(reset_gpio)) {
>> +			dev_err(&client->dev, "request for reset pin failed\n");
> I'm not confident that the error message is wanted here, you may consider either
> to remove it or at least print it out if (PTR_ERR(reset_gpio) != -EPROBE_DEFER).

no problem, I just removed it.


Steve

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Rob Herring]

On Mon, Jan 02, 2017 at 01:07:51PM -0800, Steve Longerbeam wrote:
> Add optional reset-gpios pin control. If present, de-assert the
> specified reset gpio pin to bring the chip out of reset.
> 
> Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: linux-gpio@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
>  drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> index 08dd15f..da54f4c 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> @@ -29,6 +29,10 @@ Required properties:
>  	onsemi,pca9654
>  	exar,xra1202
>  
> +Optional properties:
> + - reset-gpios: GPIO specification for the RESET input

Need to specify active high or low.

> +
> +
>  Example:
>  
>  

Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

On 01/04/2017 05:22 AM, Rob Herring wrote:
> On Mon, Jan 02, 2017 at 01:07:51PM -0800, Steve Longerbeam wrote:
>> Add optional reset-gpios pin control. If present, de-assert the
>> specified reset gpio pin to bring the chip out of reset.
>>
>> Signed-off-by: Steve Longerbeam <steve_longerbeam-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>
>> Cc: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> Cc: Alexandre Courbot <gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> ---
>>   Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
>>   drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
>>   2 files changed, 15 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> index 08dd15f..da54f4c 100644
>> --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
>> @@ -29,6 +29,10 @@ Required properties:
>>   	onsemi,pca9654
>>   	exar,xra1202
>>   
>> +Optional properties:
>> + - reset-gpios: GPIO specification for the RESET input
> Need to specify active high or low.

done (it's an active low signal).

Steve

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html