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Subject[PATCH v7 3/5] leds: Add managed API to get a LED from a device driver
Date
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>
---
drivers/leds/led-class.c | 51 ++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 2 ++
2 files changed, 53 insertions(+)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 2b8f20f94128..e11177d77b4c 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -264,6 +264,57 @@ 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_led_get - Resource-managed request of a LED device
+ * @dev: LED consumer
+ * @idx: 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.
+ *
+ * NOTE: At the moment, it supports only device-tree based LED lookup
+ *
+ * @return a pointer to a LED device or ERR_PTR(errno) on failure.
+ */
+struct led_classdev *__must_check devm_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_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 6f7371bc7757..88bf2ceaabe6 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -199,6 +199,8 @@ extern 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_led_get(struct device *dev,
+ int index);

/**
* led_blink_set - set blinking with software fallback
--
2.17.1
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