[PATCH v2 0/2] of/gpio: Automatic handling of devicetree open-drain GPIO specifications.

[PATCH v2 0/2] of/gpio: Automatic handling of devicetree open-drain GPIO specifications.

[David Daney]

From: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>

Add two new flags for open-drain and open-source GPIOs and the
corresponding handling in gpiod_get() to automatically set the
corresponding flags in the GPIO system.

Changes from v1 (suggested by Alexandre Courbot):

  o Add OF_GPIO_OPEN_SOURCE
  o Add automatic propagation of the flags in gpiod_get() et al.

David Daney (2):
  of/gpio: Define OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags.
  of/gpio: Automatically decode OF_GPIO_OPEN_DRAIN and
    OF_GPIO_OPEN_SOURCE flags in gpiolib.

 drivers/gpio/gpiolib.c  | 6 ++++++
 include/linux/of_gpio.h | 2 ++
 2 files changed, 8 insertions(+)

-- 
1.7.11.7

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[PATCH v2 1/2] of/gpio: Define OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags.

[David Daney]

From: David Daney <david.daney@cavium.com>

When we have a GPIO pin connected to an open-drain network, we want a
standard way of specifying this in the device tree.  So we choose bit
1 of the flag field to indicate open drain.

A typical use case would be something like:

	enum of_gpio_flags f;
	.
	.
	.
	reset_gpio = of_get_named_gpio_flags(node, "reset", 0, &f);
	.
	.
	.
	ret = gpio_request_one(reset_gpio,
		(f & OF_GPIO_OPEN_DRAIN) ? GPIOF_OPEN_DRAIN : 0,
		 "reset");
	.
	.
	.
	gpio_direction_output(reset_gpio, 1);
	gpio_set_value(reset_gpio, 0);
	msleep(20);
	gpio_set_value(reset_gpio, 1);
	.
	.
	.

Since the same arguments hold for open-source configurations, add a
definition for OF_GPIO_OPEN_SOURCE as well.

Signed-off-by: David Daney <david.daney@cavium.com>
---
 include/linux/of_gpio.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index f14123a..cfacf5875 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -30,6 +30,8 @@ struct device_node;
  */
 enum of_gpio_flags {
 	OF_GPIO_ACTIVE_LOW = 0x1,
+	OF_GPIO_OPEN_DRAIN = 0x2,
+	OF_GPIO_OPEN_SOURCE = 0x4,
 };
 
 #ifdef CONFIG_OF_GPIO
-- 
1.7.11.7

Re: [PATCH v2 1/2] of/gpio: Define OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags.

[Alexandre Courbot]

On Wed, Feb 12, 2014 at 4:49 AM, David Daney <ddaney.cavm@gmail.com> wrote:
> From: David Daney <david.daney@cavium.com>
>
> When we have a GPIO pin connected to an open-drain network, we want a
> standard way of specifying this in the device tree.  So we choose bit
> 1 of the flag field to indicate open drain.
>
> A typical use case would be something like:
>
>         enum of_gpio_flags f;
>         .
>         .
>         .
>         reset_gpio = of_get_named_gpio_flags(node, "reset", 0, &f);
>         .
>         .
>         .
>         ret = gpio_request_one(reset_gpio,
>                 (f & OF_GPIO_OPEN_DRAIN) ? GPIOF_OPEN_DRAIN : 0,
>                  "reset");
>         .
>         .
>         .
>         gpio_direction_output(reset_gpio, 1);
>         gpio_set_value(reset_gpio, 0);
>         msleep(20);
>         gpio_set_value(reset_gpio, 1);
>         .
>         .
>         .
>
> Since the same arguments hold for open-source configurations, add a
> definition for OF_GPIO_OPEN_SOURCE as well.
>
> Signed-off-by: David Daney <david.daney@cavium.com>

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>

Re: [PATCH v2 1/2] of/gpio: Define OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags.

[Linus Walleij]

On Tue, Feb 11, 2014 at 8:49 PM, David Daney <ddaney.cavm@gmail.com> wrote:

> From: David Daney <david.daney@cavium.com>
>
> When we have a GPIO pin connected to an open-drain network, we want a
> standard way of specifying this in the device tree.  So we choose bit
> 1 of the flag field to indicate open drain.

Same comments as for v1...

Yours,
Linus Walleij

Re: [PATCH v2 1/2] of/gpio: Define OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags.

[Linus Walleij]

On Tue, Feb 11, 2014 at 8:49 PM, David Daney <ddaney.cavm@gmail.com> wrote:

>  enum of_gpio_flags {
>         OF_GPIO_ACTIVE_LOW = 0x1,
> +       OF_GPIO_OPEN_DRAIN = 0x2,
> +       OF_GPIO_OPEN_SOURCE = 0x4,
>  };

BTW I think this enum shall be deleted and replaced by
#include <dt-bindings/gpio/gpio.h> and use the definition from
there.

Yours,
Linus Walleij

[PATCH v2 2/2] of/gpio: Automatically decode OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags in gpiolib.

[David Daney]

From: David Daney <david.daney@cavium.com>

Just as gpiod_get() automatically interprets the OF_GPIO_ACTIVE_LOW
flag from the device tree, add handling for OF_GPIO_OPEN_DRAIN and
OF_GPIO_OPEN_SOURCE.

This keeps the details of handling open-drain GPIOs in the core GPIO
code, and out of the individual drivers.

Signed-off-by: David Daney <david.daney@cavium.com>
---
 drivers/gpio/gpiolib.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 50c4922..7f596d0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2307,6 +2307,12 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
 	if (of_flags & OF_GPIO_ACTIVE_LOW)
 		*flags |= GPIO_ACTIVE_LOW;
 
+	if (of_flags & OF_GPIO_OPEN_DRAIN)
+		*flags |= GPIO_OPEN_DRAIN;
+
+	if (of_flags & OF_GPIO_OPEN_SOURCE)
+		*flags |= GPIO_OPEN_SOURCE;
+
 	return desc;
 }
 #else
-- 
1.7.11.7

Re: [PATCH v2 2/2] of/gpio: Automatically decode OF_GPIO_OPEN_DRAIN and OF_GPIO_OPEN_SOURCE flags in gpiolib.

[Alexandre Courbot]

On Wed, Feb 12, 2014 at 4:50 AM, David Daney <ddaney.cavm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> From: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
>
> Just as gpiod_get() automatically interprets the OF_GPIO_ACTIVE_LOW
> flag from the device tree, add handling for OF_GPIO_OPEN_DRAIN and
> OF_GPIO_OPEN_SOURCE.
>
> This keeps the details of handling open-drain GPIOs in the core GPIO
> code, and out of the individual drivers.
>
> Signed-off-by: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/gpio/gpiolib.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 50c4922..7f596d0 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -2307,6 +2307,12 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
>         if (of_flags & OF_GPIO_ACTIVE_LOW)
>                 *flags |= GPIO_ACTIVE_LOW;
>
> +       if (of_flags & OF_GPIO_OPEN_DRAIN)
> +               *flags |= GPIO_OPEN_DRAIN;
> +
> +       if (of_flags & OF_GPIO_OPEN_SOURCE)
> +               *flags |= GPIO_OPEN_SOURCE;
> +
>         return desc;
>  }

Reviewed-by: Alexandre Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Thanks for taking the time to do this!
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