leds: Add of_led_get() and led_put()

This patch adds basic support for a kernel driver to get a LED device.
This will be used by the led-backlight driver.

Only OF version is implemented for now, and the behavior is similar to
PWM's of_pwm_get() and pwm_put().

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
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 438774315e6c480622b648b4ca437e8b10cb5a91..03ce74a2e6a9a7c0a70f1dd0fdf295458b41c4f0 100644 (file)
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -19,6 +19,7 @@
 #include <linux/spinlock.h>
 #include <linux/timer.h>
 #include <uapi/linux/uleds.h>
+#include <linux/of.h>
 #include "leds.h"
 
 static struct class *leds_class;
@@ -214,6 +215,49 @@ static int led_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ * @index: the index of the LED
+ *
+ * Returns the LED device parsed from the phandle specified in the "leds"
+ * property of a device tree node or a negative error-code on failure.
+ */
+struct led_classdev *of_led_get(struct device_node *np, int index)
+{
+       struct device *led_dev;
+       struct led_classdev *led_cdev;
+       struct device_node *led_node;
+
+       led_node = of_parse_phandle(np, "leds", index);
+       if (!led_node)
+               return ERR_PTR(-ENOENT);
+
+       led_dev = class_find_device_by_of_node(leds_class, led_node);
+       of_node_put(led_node);
+
+       if (!led_dev)
+               return ERR_PTR(-EPROBE_DEFER);
+
+       led_cdev = dev_get_drvdata(led_dev);
+
+       if (!try_module_get(led_cdev->dev->parent->driver->owner))
+               return ERR_PTR(-ENODEV);
+
+       return led_cdev;
+}
+EXPORT_SYMBOL_GPL(of_led_get);
+
+/**
+ * led_put() - release a LED device
+ * @led_cdev: LED device
+ */
+void led_put(struct led_classdev *led_cdev)
+{
+       module_put(led_cdev->dev->parent->driver->owner);
+}
+EXPORT_SYMBOL_GPL(led_put);
+
 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 242258f7d837b9184dd41883b0da5b2423b16960..dcfb6a3258662211a545b8baf2d011f4ea625f8d 100644 (file)
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -20,6 +20,7 @@
 
 struct device;
 struct led_pattern;
+struct device_node;
 /*
  * LED Core
  */
@@ -196,6 +197,9 @@ void devm_led_classdev_unregister(struct device *parent,
 void led_classdev_suspend(struct led_classdev *led_cdev);
 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);
+
 /**
  * led_blink_set - set blinking with software fallback
  * @led_cdev: the LED to start blinking