leds: delay led_set_brightness if stopping soft-blink

Delay execution of led_set_brightness() if need to stop soft-blink
timer.

This allows led_set_brightness to be called in hard-irq context even if
soft-blink was activated on that LED.

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>

4 files changed, 33 insertions, 4 deletions

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index c599095bc005..48cce18e9d6d 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -124,6 +124,16 @@ static void led_timer_function(unsigned long data)
         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 }
 
+static void set_brightness_delayed(struct work_struct *ws)
+{
+        struct led_classdev *led_cdev =
+                container_of(ws, struct led_classdev, set_brightness_work);
+
+        led_stop_software_blink(led_cdev);
+
+        __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
+}
+
 /**
  * led_classdev_suspend - suspend an led_classdev.
  * @led_cdev: the led_classdev to suspend.
@@ -191,6 +201,8 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 
         led_update_brightness(led_cdev);
 
+        INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
+
         init_timer(&led_cdev->blink_timer);
         led_cdev->blink_timer.function = led_timer_function;
         led_cdev->blink_timer.data = (unsigned long)led_cdev;
@@ -221,7 +233,10 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
         up_write(&led_cdev->trigger_lock);
 #endif
 
+        cancel_work_sync(&led_cdev->set_brightness_work);
+
         /* Stop blinking */
+        led_stop_software_blink(led_cdev);
         led_set_brightness(led_cdev, LED_OFF);
 
         device_unregister(led_cdev->dev);
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 2ab05af3de31..ce8921a753a3 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -103,13 +103,23 @@ void led_blink_set_oneshot(struct led_classdev *led_cdev,
 }
 EXPORT_SYMBOL(led_blink_set_oneshot);
 
-void led_set_brightness(struct led_classdev *led_cdev,
-                        enum led_brightness brightness)
+void led_stop_software_blink(struct led_classdev *led_cdev)
 {
-        /* stop and clear soft-blink timer */
         del_timer_sync(&led_cdev->blink_timer);
         led_cdev->blink_delay_on = 0;
         led_cdev->blink_delay_off = 0;
+}
+EXPORT_SYMBOL_GPL(led_stop_software_blink);
+
+void led_set_brightness(struct led_classdev *led_cdev,
+                        enum led_brightness brightness)
+{
+        /* delay brightness setting if need to stop soft-blink timer */
+        if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
+                led_cdev->delayed_set_value = brightness;
+                schedule_work(&led_cdev->set_brightness_work);
+                return;
+        }
 
         __led_set_brightness(led_cdev, brightness);
 }
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 363975b3c925..b53bf54023f6 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -109,6 +109,8 @@ void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
                 list_del(&led_cdev->trig_list);
                 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
                         flags);
+                cancel_work_sync(&led_cdev->set_brightness_work);
+                led_stop_software_blink(led_cdev);
                 if (led_cdev->trigger->deactivate)
                         led_cdev->trigger->deactivate(led_cdev);
                 led_cdev->trigger = NULL;
@@ -224,7 +226,7 @@ void led_trigger_event(struct led_trigger *trig,
                 struct led_classdev *led_cdev;
 
                 led_cdev = list_entry(entry, struct led_classdev, trig_list);
-                __led_set_brightness(led_cdev, brightness);
+                led_set_brightness(led_cdev, brightness);
         }
         read_unlock(&trig->leddev_list_lock);
 }
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index d02acd496126..4c50365344a9 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -32,6 +32,8 @@ static inline int led_get_brightness(struct led_classdev *led_cdev)
         return led_cdev->brightness;
 }
 
+void led_stop_software_blink(struct led_classdev *led_cdev);
+
 extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;