From: David Daney <[email protected]>
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
From: David Daney <[email protected]>
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 <[email protected]>
---
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
From: David Daney <[email protected]>
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 <[email protected]>
---
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
On Wed, Feb 12, 2014 at 4:49 AM, David Daney <[email protected]> wrote:
> From: David Daney <[email protected]>
>
> 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 <[email protected]>
Reviewed-by: Alexandre Courbot <[email protected]>
On Wed, Feb 12, 2014 at 4:50 AM, David Daney <[email protected]> wrote:
> From: David Daney <[email protected]>
>
> 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 <[email protected]>
> ---
> 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 <[email protected]>
Thanks for taking the time to do this!
On Tue, Feb 11, 2014 at 8:49 PM, David Daney <[email protected]> wrote:
> From: David Daney <[email protected]>
>
> 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
On Tue, Feb 11, 2014 at 8:49 PM, David Daney <[email protected]> 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