leds: core: Use set_brightness_work for the blocking op

This patch makes LED core capable of setting brightness for drivers
that implement brightness_set_blocking op. It removes from LED class
drivers responsibility for using work queues on their own.

In order to achieve this set_brightness_delayed callback is being
modified to directly call one of available ops for brightness setting.

led_set_brightness_async() function didn't set brightness in an
asynchronous way in all cases. It was mistakenly assuming that all
LED subsystem drivers used work queue in their brightness_set op,
whereas only half of them did that. Since it has no users now,
it is being removed.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

drivers/leds/led-core.c

@@ -83,6 +83,7 @@ static void set_brightness_delayed(struct work_struct *ws)
 {
 	struct led_classdev *led_cdev =
 		container_of(ws, struct led_classdev, set_brightness_work);
+	int ret = 0;
 
 	if (led_cdev->flags & LED_BLINK_DISABLE) {
 		led_cdev->delayed_set_value = LED_OFF;
@@ -90,7 +91,16 @@ static void set_brightness_delayed(struct work_struct *ws)
 		led_cdev->flags &= ~LED_BLINK_DISABLE;
 	}
 
-	led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
+	if (led_cdev->brightness_set)
+		led_cdev->brightness_set(led_cdev, led_cdev->delayed_set_value);
+	else if (led_cdev->brightness_set_blocking)
+		ret = led_cdev->brightness_set_blocking(led_cdev,
+						led_cdev->delayed_set_value);
+	else
+		ret = -ENOTSUPP;
+	if (ret < 0)
+		dev_err(led_cdev->dev,
+			"Setting an LED's brightness failed (%d)\n", ret);
 }
 
 static void led_set_software_blink(struct led_classdev *led_cdev,

drivers/leds/leds.h

@@ -16,16 +16,6 @@
 #include <linux/rwsem.h>
 #include <linux/leds.h>
 
-static inline void led_set_brightness_async(struct led_classdev *led_cdev,
-					enum led_brightness value)
-{
-	value = min(value, led_cdev->max_brightness);
-	led_cdev->brightness = value;
-
-	if (!(led_cdev->flags & LED_SUSPENDED))
-		led_cdev->brightness_set(led_cdev, value);
-}
-
 static inline int led_set_brightness_sync(struct led_classdev *led_cdev,
 					enum led_brightness value)
 {

include/linux/leds.h

@@ -158,7 +158,7 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
  *
  * Set an LED's brightness, and, if necessary, cancel the
  * software blink timer that implements blinking when the
- * hardware doesn't.
+ * hardware doesn't. This function is guaranteed not to sleep.
  */
 extern void led_set_brightness(struct led_classdev *led_cdev,
 			       enum led_brightness brightness);