Hello!
Any comment on this?
Thanks!
On Thu, Dec 17, 2015 at 5:48 PM, Ricardo Ribalda Delgado
<ricardo.riba...@gmail.com> wrote:
> On named GPIOs there is currently no find out their numerical id.
>
> Because of this, a GPIO pin named like:
> /sys/class/gpio/PROG_B
>
> cannot be unexported by an application different than the one that
> exported it.
>
> This patch adds a new parameter to the GPIO line called id, that
> shows the numerical id of a given GPIO. E.g.:
>
> $ cat /sys/class/gpio/PROG_B/id
> 496
> $ echo 496 > unexport
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.riba...@gmail.com>
> ---
> Documentation/ABI/testing/sysfs-gpio | 1 +
> Documentation/gpio/sysfs.txt | 3 +++
> drivers/gpio/gpiolib-sysfs.c | 10 ++++++++++
> 3 files changed, 14 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-gpio
> b/Documentation/ABI/testing/sysfs-gpio
> index 55ffa2df1c10..53d78abef4f3 100644
> --- a/Documentation/ABI/testing/sysfs-gpio
> +++ b/Documentation/ABI/testing/sysfs-gpio
> @@ -21,6 +21,7 @@ Description:
> /value ... always readable, writes fail for input GPIOs
> /direction ... r/w as: in, out (default low); write: high, low
> /edge ... r/w as: none, falling, rising, both
> + /id ... r only, GPIO number
> /gpiochipN ... for each gpiochip; #N is its first GPIO
> /base ... (r/o) same as N
> /label ... (r/o) descriptive, not necessarily unique
> diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt
> index aeab01aa4d00..68e1b16e747b 100644
> --- a/Documentation/gpio/sysfs.txt
> +++ b/Documentation/gpio/sysfs.txt
> @@ -96,6 +96,9 @@ and have the following read/write attributes:
> for "rising" and "falling" edges will follow this
> setting.
>
> + "id" ... ID used for export/unxexport the GPIO. This value may
> + be used by named GPIOs, to find out their numerical id.
> +
> GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the
> controller implementing GPIOs starting at #42) and have the following
> read-only attributes:
> diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
> index b57ed8e55ab5..3fc5c7231aae 100644
> --- a/drivers/gpio/gpiolib-sysfs.c
> +++ b/drivers/gpio/gpiolib-sysfs.c
> @@ -350,6 +350,15 @@ static ssize_t active_low_store(struct device *dev,
> }
> static DEVICE_ATTR_RW(active_low);
>
> +static ssize_t id_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct gpiod_data *data = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%d\n", desc_to_gpio(data->desc));
> +}
> +static DEVICE_ATTR_RO(id);
> +
> static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
> int n)
> {
> @@ -377,6 +386,7 @@ static struct attribute *gpio_attrs[] = {
> &dev_attr_edge.attr,
> &dev_attr_value.attr,
> &dev_attr_active_low.attr,
> + &dev_attr_id.attr,
> NULL,
> };
>
> --
> 2.6.4
>
--
Ricardo Ribalda
