leds: core: Drivers shouldn't enforce SYNC/ASYNC brightness setting

This patch removes SET_BRIGHTNESS_ASYNC and SET_BRIGHTNESS_SYNC flags.
led_set_brightness() now calls led_set_brightness_nosleep() instead of
choosing between sync and async op basing on the flags defined by the
driver.

From now on, if a user wants to make sure that brightness will be set
synchronously, they have to use led_set_brightness_sync() API. It is now
being made publicly available since it has become apparent that it is
a caller who should decide whether brightness is to be set in
a synchronous or an asynchronous way.

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

drivers/leds/led-class-flash.c

@@ -316,10 +316,6 @@ int led_classdev_flash_register(struct device *parent,
 	if (ret < 0)
 		return ret;
 
-	/* Setting a torch brightness needs to have immediate effect */
-	led_cdev->flags &= ~SET_BRIGHTNESS_ASYNC;
-	led_cdev->flags |= SET_BRIGHTNESS_SYNC;
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(led_classdev_flash_register);

drivers/leds/led-class.c

@@ -215,8 +215,6 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 	if (!led_cdev->max_brightness)
 		led_cdev->max_brightness = LED_FULL;
 
-	led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
-
 	led_update_brightness(led_cdev);
 
 	led_init_core(led_cdev);

drivers/leds/led-core.c

@@ -205,8 +205,6 @@ EXPORT_SYMBOL_GPL(led_stop_software_blink);
 void led_set_brightness(struct led_classdev *led_cdev,
 			enum led_brightness brightness)
 {
-	int ret = 0;
-
 	/*
 	 * In case blinking is on delay brightness setting
 	 * until the next timer tick.
@@ -227,17 +225,7 @@ void led_set_brightness(struct led_classdev *led_cdev,
 		return;
 	}
 
-	if (led_cdev->flags & SET_BRIGHTNESS_ASYNC) {
+	led_set_brightness_nosleep(led_cdev, brightness);
-		led_set_brightness_nosleep(led_cdev, brightness);
-		return;
-	} else if (led_cdev->flags & SET_BRIGHTNESS_SYNC)
-		ret = led_set_brightness_sync(led_cdev, brightness);
-	else
-		ret = -EINVAL;
-
-	if (ret < 0)
-		dev_dbg(led_cdev->dev, "Setting LED brightness failed (%d)\n",
-			ret);
 }
 EXPORT_SYMBOL_GPL(led_set_brightness);
 
@@ -268,6 +256,24 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 }
 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 
+int led_set_brightness_sync(struct led_classdev *led_cdev,
+			    enum led_brightness value)
+{
+	if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
+		return -EBUSY;
+
+	led_cdev->brightness = min(value, led_cdev->max_brightness);
+
+	if (led_cdev->flags & LED_SUSPENDED)
+		return 0;
+
+	if (led_cdev->brightness_set_blocking)
+		return led_cdev->brightness_set_blocking(led_cdev,
+							 led_cdev->brightness);
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL_GPL(led_set_brightness_sync);
+
 int led_update_brightness(struct led_classdev *led_cdev)
 {
 	int ret = 0;

drivers/leds/leds.h

@@ -16,19 +16,6 @@
 #include <linux/rwsem.h>
 #include <linux/leds.h>
 
-static inline int led_set_brightness_sync(struct led_classdev *led_cdev,
-					enum led_brightness value)
-{
-	int ret = 0;
-
-	led_cdev->brightness = min(value, led_cdev->max_brightness);
-
-	if (!(led_cdev->flags & LED_SUSPENDED))
-		ret = led_cdev->brightness_set_blocking(led_cdev,
-						led_cdev->brightness);
-	return ret;
-}
-
 static inline int led_get_brightness(struct led_classdev *led_cdev)
 {
 	return led_cdev->brightness;

include/linux/leds.h

@@ -47,9 +47,7 @@ struct led_classdev {
 #define LED_BLINK_BRIGHTNESS_CHANGE (1 << 20)
 #define LED_BLINK_DISABLE	(1 << 21)
 #define LED_SYSFS_DISABLE	(1 << 22)
-#define SET_BRIGHTNESS_ASYNC	(1 << 23)
+#define LED_DEV_CAP_FLASH	(1 << 23)
-#define SET_BRIGHTNESS_SYNC	(1 << 24)
-#define LED_DEV_CAP_FLASH	(1 << 25)
 
 	/* Set LED brightness level */
 	/* Must not sleep, use a workqueue if needed */
@@ -162,6 +160,21 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
  */
 extern void led_set_brightness(struct led_classdev *led_cdev,
 			       enum led_brightness brightness);
+
+/**
+ * led_set_brightness_sync - set LED brightness synchronously
+ * @led_cdev: the LED to set
+ * @brightness: the brightness to set it to
+ *
+ * Set an LED's brightness immediately. This function will block
+ * the caller for the time required for accessing device registers,
+ * and it can sleep.
+ *
+ * Returns: 0 on success or negative error value on failure
+ */
+extern int led_set_brightness_sync(struct led_classdev *led_cdev,
+				   enum led_brightness value);
+
 /**
  * led_update_brightness - update LED brightness
  * @led_cdev: the LED to query