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gpiolib: acpi: Introduce acpi_get_and_request_gpiod() helper

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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.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Daniel Scally 2021-06-03 23:40:04 +01:00 committed by Andy Shevchenko
parent 2b71b66ac0
commit 43582f29b1
2 changed files with 30 additions and 0 deletions
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28
drivers/gpio/gpiolib-acpi.c
View File

@ -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;

2
include/linux/gpio/consumer.h
View File

@ -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;