leds: convert blink timer to workqueue

This patch converts the blink timer from led-core to workqueue which is more
suitable for this kind of non-priority operations. Moreover, timer may lead to
errors when a LED setting function use a scheduling function such as pinctrl
which is using mutex.

Signed-off-by: Vincent Donnefort <vdonnefort@gmail.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

2 files changed, 13 insertions, 12 deletions

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index aa29198fca3e..129729d35478 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -15,10 +15,10 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/device.h>
-#include <linux/timer.h>
 #include <linux/err.h>
 #include <linux/ctype.h>
 #include <linux/leds.h>
+#include <linux/workqueue.h>
 #include "leds.h"
 
 static struct class *leds_class;
@@ -97,9 +97,10 @@ static const struct attribute_group *led_groups[] = {
         NULL,
 };
 
-static void led_timer_function(unsigned long data)
+static void led_work_function(struct work_struct *ws)
 {
-        struct led_classdev *led_cdev = (void *)data;
+        struct led_classdev *led_cdev =
+                container_of(ws, struct led_classdev, blink_work.work);
         unsigned long brightness;
         unsigned long delay;
 
@@ -143,7 +144,8 @@ static void led_timer_function(unsigned long data)
                 }
         }
 
-        mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
+        queue_delayed_work(system_wq, &led_cdev->blink_work,
+                           msecs_to_jiffies(delay));
 }
 
 static void set_brightness_delayed(struct work_struct *ws)
@@ -231,9 +233,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *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;
+        INIT_DELAYED_WORK(&led_cdev->blink_work, led_work_function);
 
 #ifdef CONFIG_LEDS_TRIGGERS
         led_trigger_set_default(led_cdev);
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 71b40d3bf776..4bb116867b88 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/rwsem.h>
 #include <linux/leds.h>
+#include <linux/workqueue.h>
 #include "leds.h"
 
 DECLARE_RWSEM(leds_list_lock);
@@ -51,7 +52,7 @@ static void led_set_software_blink(struct led_classdev *led_cdev,
                 return;
         }
 
-        mod_timer(&led_cdev->blink_timer, jiffies + 1);
+        queue_delayed_work(system_wq, &led_cdev->blink_work, 1);
 }
 
 
@@ -75,7 +76,7 @@ void led_blink_set(struct led_classdev *led_cdev,
                    unsigned long *delay_on,
                    unsigned long *delay_off)
 {
-        del_timer_sync(&led_cdev->blink_timer);
+        cancel_delayed_work_sync(&led_cdev->blink_work);
 
         led_cdev->flags &= ~LED_BLINK_ONESHOT;
         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
@@ -90,7 +91,7 @@ void led_blink_set_oneshot(struct led_classdev *led_cdev,
                            int invert)
 {
         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
-             timer_pending(&led_cdev->blink_timer))
+             delayed_work_pending(&led_cdev->blink_work))
                 return;
 
         led_cdev->flags |= LED_BLINK_ONESHOT;
@@ -107,7 +108,7 @@ EXPORT_SYMBOL(led_blink_set_oneshot);
 
 void led_stop_software_blink(struct led_classdev *led_cdev)
 {
-        del_timer_sync(&led_cdev->blink_timer);
+        cancel_delayed_work_sync(&led_cdev->blink_work);
         led_cdev->blink_delay_on = 0;
         led_cdev->blink_delay_off = 0;
 }
@@ -116,7 +117,7 @@ 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 */
+        /* delay brightness setting if need to stop soft-blink work */
         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
                 led_cdev->delayed_set_value = brightness;
                 schedule_work(&led_cdev->set_brightness_work);