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>

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 03ce74a..0868f84 100644 (file)
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -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)
 {

diff --git a/include/linux/leds.h b/include/linux/leds.h
index dcfb6a3..75353e5 100644 (file)
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -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