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>

9 files changed, 55 insertions, 23 deletions

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 7385f98dd54b..83a1dc725864 100644
--- a/drivers/leds/led-class.c
+++ b/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);
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 7cf59243e0ef..3d168592db65 100644
--- a/drivers/leds/led-core.c
+++ b/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;
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index cf6d44886bcb..8e252a2f8662 100644
--- a/drivers/leds/leds.h
+++ b/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;
diff --git a/drivers/leds/trigger/ledtrig-backlight.c b/drivers/leds/trigger/ledtrig-backlight.c
index 59eca17d9661..1ca1f1608f76 100644
--- a/drivers/leds/trigger/ledtrig-backlight.c
+++ b/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;
 }
diff --git a/drivers/leds/trigger/ledtrig-default-on.c b/drivers/leds/trigger/ledtrig-default-on.c
index 6f38f883aaf1..ff455cb46680 100644
--- a/drivers/leds/trigger/ledtrig-default-on.c
+++ b/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 = {
diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c
index 4cc7040746c6..51288a45fbcb 100644
--- a/drivers/leds/trigger/ledtrig-gpio.c
+++ b/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);
         }
 }
 
diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c
index 8622ce651ae2..410c39c62dc7 100644
--- a/drivers/leds/trigger/ledtrig-heartbeat.c
+++ b/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);
 }
 
diff --git a/drivers/leds/trigger/ledtrig-oneshot.c b/drivers/leds/trigger/ledtrig-oneshot.c
index fbd02cdc3ad7..67293177a07b 100644
--- a/drivers/leds/trigger/ledtrig-oneshot.c
+++ b/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;
 }
diff --git a/drivers/leds/trigger/ledtrig-transient.c b/drivers/leds/trigger/ledtrig-transient.c
index 3c34de404d18..1dddd8f63e2a 100644
--- a/drivers/leds/trigger/ledtrig-transient.c
+++ b/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);