leds: core: Add led_set_brightness_nosleep{nopm} functions

This patch adds led_set_brightness_nosleep() and led_set_brightness_nopm()
functions, that guarantee setting LED brightness in a non-blocking way.
The latter is used from pm_ops context and doesn't modify the brightness
cached in the struct led_classdev. Its execution always ends up with
a call to brightness setting op - either directly or through
a set_brightness_work, regardless of LED_SUSPENDED flag state.

The patch also replaces led_set_brightness_async() with
led_set_brightness_nosleep() in all places where the most vital was setting
brightness in a non sleeping way but not necessarily asynchronously, which
is not needed for non-blocking drivers.
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

drivers/leds/led-class.c

@@ -109,7 +109,7 @@ static const struct attribute_group *led_groups[] = {
 void led_classdev_suspend(struct led_classdev *led_cdev)
 {
 	led_cdev->flags |= LED_SUSPENDED;
-	led_cdev->brightness_set(led_cdev, 0);
+	led_set_brightness_nopm(led_cdev, 0);
 }
 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 
@@ -119,7 +119,7 @@ EXPORT_SYMBOL_GPL(led_classdev_suspend);
  */
 void led_classdev_resume(struct led_classdev *led_cdev)
 {
-	led_cdev->brightness_set(led_cdev, led_cdev->brightness);
+	led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 
 	if (led_cdev->flash_resume)
 		led_cdev->flash_resume(led_cdev);

drivers/leds/led-core.c

@@ -32,7 +32,7 @@ static void led_timer_function(unsigned long data)
 	unsigned long delay;
 
 	if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
-		led_set_brightness_async(led_cdev, LED_OFF);
+		led_set_brightness_nosleep(led_cdev, LED_OFF);
 		return;
 	}
 
@@ -60,7 +60,7 @@ static void led_timer_function(unsigned long data)
 		delay = led_cdev->blink_delay_off;
 	}
 
-	led_set_brightness_async(led_cdev, brightness);
+	led_set_brightness_nosleep(led_cdev, brightness);
 
 	/* Return in next iteration if led is in one-shot mode and we are in
 	 * the final blink state so that the led is toggled each delay_on +
@@ -110,13 +110,14 @@ static void led_set_software_blink(struct led_classdev *led_cdev,
 
 	/* never on - just set to off */
 	if (!delay_on) {
-		led_set_brightness_async(led_cdev, LED_OFF);
+		led_set_brightness_nosleep(led_cdev, LED_OFF);
 		return;
 	}
 
 	/* never off - just set to brightness */
 	if (!delay_off) {
-		led_set_brightness_async(led_cdev, led_cdev->blink_brightness);
+		led_set_brightness_nosleep(led_cdev,
+					   led_cdev->blink_brightness);
 		return;
 	}
 
@@ -217,7 +218,7 @@ void led_set_brightness(struct led_classdev *led_cdev,
 	}
 
 	if (led_cdev->flags & SET_BRIGHTNESS_ASYNC) {
-		led_set_brightness_async(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);
@@ -230,6 +231,33 @@ void led_set_brightness(struct led_classdev *led_cdev,
 }
 EXPORT_SYMBOL_GPL(led_set_brightness);
 
+void led_set_brightness_nopm(struct led_classdev *led_cdev,
+			      enum led_brightness value)
+{
+	/* Use brightness_set op if available, it is guaranteed not to sleep */
+	if (led_cdev->brightness_set) {
+		led_cdev->brightness_set(led_cdev, value);
+		return;
+	}
+
+	/* If brightness setting can sleep, delegate it to a work queue task */
+	led_cdev->delayed_set_value = value;
+	schedule_work(&led_cdev->set_brightness_work);
+}
+EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
+
+void led_set_brightness_nosleep(struct led_classdev *led_cdev,
+				enum led_brightness value)
+{
+	led_cdev->brightness = min(value, led_cdev->max_brightness);
+
+	if (led_cdev->flags & LED_SUSPENDED)
+		return;
+
+	led_set_brightness_nopm(led_cdev, led_cdev->brightness);
+}
+EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
+
 int led_update_brightness(struct led_classdev *led_cdev)
 {
 	int ret = 0;

drivers/leds/leds.h

@@ -46,6 +46,10 @@ static inline int led_get_brightness(struct led_classdev *led_cdev)
 
 void led_init_core(struct led_classdev *led_cdev);
 void led_stop_software_blink(struct led_classdev *led_cdev);
+void led_set_brightness_nopm(struct led_classdev *led_cdev,
+				enum led_brightness value);
+void led_set_brightness_nosleep(struct led_classdev *led_cdev,
+				enum led_brightness value);
 
 extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;

drivers/leds/trigger/ledtrig-backlight.c

@@ -51,9 +51,9 @@ static int fb_notifier_callback(struct notifier_block *p,
 
 	if ((n->old_status == UNBLANK) ^ n->invert) {
 		n->brightness = led->brightness;
-		led_set_brightness_async(led, LED_OFF);
+		led_set_brightness_nosleep(led, LED_OFF);
 	} else {
-		led_set_brightness_async(led, n->brightness);
+		led_set_brightness_nosleep(led, n->brightness);
 	}
 
 	n->old_status = new_status;
@@ -89,9 +89,9 @@ static ssize_t bl_trig_invert_store(struct device *dev,
 
 	/* After inverting, we need to update the LED. */
 	if ((n->old_status == BLANK) ^ n->invert)
-		led_set_brightness_async(led, LED_OFF);
+		led_set_brightness_nosleep(led, LED_OFF);
 	else
-		led_set_brightness_async(led, n->brightness);
+		led_set_brightness_nosleep(led, n->brightness);
 
 	return num;
 }

drivers/leds/trigger/ledtrig-default-on.c

@@ -19,7 +19,7 @@
 
 static void defon_trig_activate(struct led_classdev *led_cdev)
 {
-	led_set_brightness_async(led_cdev, led_cdev->max_brightness);
+	led_set_brightness_nosleep(led_cdev, led_cdev->max_brightness);
 }
 
 static struct led_trigger defon_led_trigger = {

drivers/leds/trigger/ledtrig-gpio.c

@@ -54,12 +54,12 @@ static void gpio_trig_work(struct work_struct *work)
 
 	if (tmp) {
 		if (gpio_data->desired_brightness)
-			led_set_brightness_async(gpio_data->led,
+			led_set_brightness_nosleep(gpio_data->led,
 					   gpio_data->desired_brightness);
 		else
-			led_set_brightness_async(gpio_data->led, LED_FULL);
+			led_set_brightness_nosleep(gpio_data->led, LED_FULL);
 	} else {
-		led_set_brightness_async(gpio_data->led, LED_OFF);
+		led_set_brightness_nosleep(gpio_data->led, LED_OFF);
 	}
 }
 

drivers/leds/trigger/ledtrig-heartbeat.c

@@ -38,7 +38,7 @@ static void led_heartbeat_function(unsigned long data)
 	unsigned long delay = 0;
 
 	if (unlikely(panic_heartbeats)) {
-		led_set_brightness(led_cdev, LED_OFF);
+		led_set_brightness_nosleep(led_cdev, LED_OFF);
 		return;
 	}
 
@@ -81,7 +81,7 @@ static void led_heartbeat_function(unsigned long data)
 		break;
 	}
 
-	led_set_brightness_async(led_cdev, brightness);
+	led_set_brightness_nosleep(led_cdev, brightness);
 	mod_timer(&heartbeat_data->timer, jiffies + delay);
 }
 

drivers/leds/trigger/ledtrig-oneshot.c

@@ -63,9 +63,9 @@ static ssize_t led_invert_store(struct device *dev,
 	oneshot_data->invert = !!state;
 
 	if (oneshot_data->invert)
-		led_set_brightness_async(led_cdev, LED_FULL);
+		led_set_brightness_nosleep(led_cdev, LED_FULL);
 	else
-		led_set_brightness_async(led_cdev, LED_OFF);
+		led_set_brightness_nosleep(led_cdev, LED_OFF);
 
 	return size;
 }

drivers/leds/trigger/ledtrig-transient.c

@@ -41,7 +41,7 @@ static void transient_timer_function(unsigned long data)
 	struct transient_trig_data *transient_data = led_cdev->trigger_data;
 
 	transient_data->activate = 0;
-	led_set_brightness_async(led_cdev, transient_data->restore_state);
+	led_set_brightness_nosleep(led_cdev, transient_data->restore_state);
 }
 
 static ssize_t transient_activate_show(struct device *dev,
@@ -72,7 +72,7 @@ static ssize_t transient_activate_store(struct device *dev,
 	if (state == 0 && transient_data->activate == 1) {
 		del_timer(&transient_data->timer);
 		transient_data->activate = state;
-		led_set_brightness_async(led_cdev,
+		led_set_brightness_nosleep(led_cdev,
 					transient_data->restore_state);
 		return size;
 	}
@@ -81,7 +81,7 @@ static ssize_t transient_activate_store(struct device *dev,
 	if (state == 1 && transient_data->activate == 0 &&
 	    transient_data->duration != 0) {
 		transient_data->activate = state;
-		led_set_brightness_async(led_cdev, transient_data->state);
+		led_set_brightness_nosleep(led_cdev, transient_data->state);
 		transient_data->restore_state =
 		    (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
 		mod_timer(&transient_data->timer,
@@ -204,7 +204,7 @@ static void transient_trig_deactivate(struct led_classdev *led_cdev)
 
 	if (led_cdev->activated) {
 		del_timer_sync(&transient_data->timer);
-		led_set_brightness_async(led_cdev,
+		led_set_brightness_nosleep(led_cdev,
 					transient_data->restore_state);
 		device_remove_file(led_cdev->dev, &dev_attr_activate);
 		device_remove_file(led_cdev->dev, &dev_attr_duration);