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leds: Add managed API to get a LED from a device driver 

If the LED is acquired by a consumer device with devm_led_get(), it is
automatically released when the device is detached.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
This commit is contained in:
Jean-Jacques Hiblot 2019-10-03 10:28:10 +02:00 committed by Pavel
parent 699a8c7c4b
commit e389240ad9
2 changed files with 51 additions and 0 deletions
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49
drivers/leds/led-class.c
View File

@ -258,6 +258,55 @@ void led_put(struct led_classdev *led_cdev)
}
EXPORT_SYMBOL_GPL(led_put);
static void devm_led_release(struct device *dev, void *res)
{
struct led_classdev **p = res;
led_put(*p);
}
/**
* devm_of_led_get - Resource-managed request of a LED device
* @dev: LED consumer
* @index: index of the LED to obtain in the consumer
*
* The device node of the device is parse to find the request LED device.
* The LED device returned from this function is automatically released
* on driver detach.
*
* @return a pointer to a LED device or ERR_PTR(errno) on failure.
*/
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index)
{
struct led_classdev *led;
struct led_classdev **dr;
if (!dev)
return ERR_PTR(-EINVAL);
/* Not using device tree? */
if (!IS_ENABLED(CONFIG_OF) || !dev->of_node)
return ERR_PTR(-ENOTSUPP);
led = of_led_get(dev->of_node, index);
if (IS_ERR(led))
return led;
dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
GFP_KERNEL);
if (!dr) {
led_put(led);
return ERR_PTR(-ENOMEM);
}
*dr = led;
devres_add(dev, dr);
return led;
}
EXPORT_SYMBOL_GPL(devm_of_led_get);
static int led_classdev_next_name(const char *init_name, char *name,
size_t len)
{

2
include/linux/leds.h
View File

@ -199,6 +199,8 @@ void led_classdev_resume(struct led_classdev *led_cdev);
extern struct led_classdev *of_led_get(struct device_node *np, int index);
extern void led_put(struct led_classdev *led_cdev);
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index);
/**
* led_blink_set - set blinking with software fallback