[PATCH 10/13] leds: backlight trigger: Maintain global list of led backlight triggers

[Thomas Zimmermann]

Maintain a list of led backlight triggers. This will replace the
fbdev notifiers that all backlight triggers currently subscribe to.

Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
---
 drivers/leds/trigger/ledtrig-backlight.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/leds/trigger/ledtrig-backlight.c 
b/drivers/leds/trigger/ledtrig-backlight.c
index 487577d22cfc..c1c1aa60cf07 100644
--- a/drivers/leds/trigger/ledtrig-backlight.c
+++ b/drivers/leds/trigger/ledtrig-backlight.c
@@ -23,8 +23,13 @@ struct bl_trig_notifier {
        int old_status;
        struct notifier_block notifier;
        unsigned invert;
+
+       struct list_head entry;
 };
 
+static struct list_head ledtrig_backlight_list;
+static struct mutex ledtrig_backlight_list_mutex;
+
 static int fb_notifier_callback(struct notifier_block *p,
                                unsigned long event, void *data)
 {
@@ -118,6 +123,10 @@ static int bl_trig_activate(struct led_classdev *led)
        if (ret)
                dev_err(led->dev, "unable to register backlight trigger\n");
 
+       mutex_lock(&ledtrig_backlight_list_mutex);
+       list_add(&n->entry, &ledtrig_backlight_list);
+       mutex_unlock(&ledtrig_backlight_list_mutex);
+
        return 0;
 }
 
@@ -125,6 +134,10 @@ static void bl_trig_deactivate(struct led_classdev *led)
 {
        struct bl_trig_notifier *n = led_get_trigger_data(led);
 
+       mutex_lock(&ledtrig_backlight_list_mutex);
+       list_del(&n->entry);
+       mutex_unlock(&ledtrig_backlight_list_mutex);
+
        fb_unregister_client(&n->notifier);
        kfree(n);
 }
-- 
2.48.1