This patch adds led_set_brightness_nosleep function. It guarantees setting
LED brightness in a non-blocking way.

Signed-off-by: Jacek Anaszewski <[email protected]>
Cc: Bryan Wu <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: Sakari Ailus <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Stas Sergeev <[email protected]>
---
 drivers/leds/leds.h  |   22 ++++++++++++++++++++++
 include/linux/leds.h |    2 +-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index f700400..308f60f 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -2,8 +2,10 @@
  * LED Core
  *
  * Copyright 2005 Openedhand Ltd.
+ * Copyright 2014, 2015 Samsung Electronics Co., Ltd.
  *
  * Author: Richard Purdie <[email protected]>
+ * Author: Jacek Anaszewski <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -39,6 +41,26 @@ static inline void led_set_brightness_async(struct 
led_classdev *led_cdev,
        schedule_work(&led_cdev->set_brightness_work);
 }
 
+static inline void led_set_brightness_nosleep(struct led_classdev *led_cdev,
+                                             enum led_brightness value)
+{
+       int ret;
+
+       /*
+        * Drivers that implement brightness_set_nonblocking op are guaranteed
+        * not to sleep while setting brightness.
+        */
+       if (led_cdev->brightness_set_nonblocking) {
+               ret = led_set_brightness_sync(led_cdev, value);
+               if (ret < 0)
+                       dev_err(led_cdev->dev,
+                               "cannot set led brightness %d\n", ret);
+               return;
+       }
+
+       led_set_brightness_async(led_cdev, value);
+}
+
 static inline int led_get_brightness(struct led_classdev *led_cdev)
 {
        return led_cdev->brightness;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index a004e84..9603a73 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -52,7 +52,7 @@ struct led_classdev {
 #define LED_BLINK_DISABLE      (1 << 25)
 
        /* Set LED brightness level */
-       /* Must not sleep, use a workqueue if needed */
+       /* Intended for drivers that may set brightness in a blocking way. */
        void            (*brightness_set)(struct led_classdev *led_cdev,
                                          enum led_brightness brightness);
        /* Intended for drivers that set brightness in a non-blocking way */
-- 
1.7.9.5

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