On Thu, Jun 03, 2021 at 11:40:04PM +0100, Daniel Scally wrote:
> We need to be able to translate GPIO resources in an ACPI device's _CRS
> into GPIO descriptor array. Those are represented in _CRS as a pathname
> to a GPIO device plus the pin's index number: the acpi_get_gpiod()
> function is perfect for that purpose.
>
> As it's currently only used internally within the GPIO layer, provide and
> export a wrapper function that additionally holds a reference to the GPIO
> device.
The subject is wrong, it should be "Introduce acpi_get_and_request_gpiod()
helper" or so. I can fix when applying.
Btw, do I understand correctly that I may push GPIO ACPI patches independently
(of the ACPI changes)?
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
> ---
> Changes since v4:
> - None
>
> drivers/gpio/gpiolib-acpi.c | 28 ++++++++++++++++++++++++++++
> include/linux/gpio/consumer.h | 2 ++
> 2 files changed, 30 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index 5b4111e4be3f..684ddb35d83b 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -128,6 +128,34 @@ static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
> return gpiochip_get_desc(chip, pin);
> }
>
> +/**
> + * acpi_get_and_request_gpiod() - Translate ACPI GPIO pin to GPIO descriptor
> + * and hold a refcount to the GPIO device.
> + * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
> + * @pin: ACPI GPIO pin number (0-based, controller-relative)
> + * @label: Label to pass to gpiod_request()
> + *
> + * This function is a simple pass-through to acpi_get_gpiod(), except that
> + * as it is intended for use outside of the GPIO layer (in a similar fashion to
> + * gpiod_get_index() for example) it also holds a reference to the GPIO device.
> + */
> +struct gpio_desc *acpi_get_and_request_gpiod(char *path, int pin, char *label)
> +{
> + struct gpio_desc *gpio;
> + int ret;
> +
> + gpio = acpi_get_gpiod(path, pin);
> + if (IS_ERR(gpio))
> + return gpio;
> +
> + ret = gpiod_request(gpio, label);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return gpio;
> +}
> +EXPORT_SYMBOL_GPL(acpi_get_and_request_gpiod);
> +
> static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
> {
> struct acpi_gpio_event *event = data;
> diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
> index c73b25bc9213..566feb56601f 100644
> --- a/include/linux/gpio/consumer.h
> +++ b/include/linux/gpio/consumer.h
> @@ -692,6 +692,8 @@ int devm_acpi_dev_add_driver_gpios(struct device *dev,
> const struct acpi_gpio_mapping *gpios);
> void devm_acpi_dev_remove_driver_gpios(struct device *dev);
>
> +struct gpio_desc *acpi_get_and_request_gpiod(char *path, int pin, char *label);
> +
> #else /* CONFIG_GPIOLIB && CONFIG_ACPI */
>
> struct acpi_device;
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
