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Subject[PATCH] leds: trigger: timer: Optionally stop timer trigger on reboot
Date
This functionality is similar to heartbeat and activity triggers and
turns the timer-triggered LEDs off right before reboot. It's configurable
via new module parameter "reboot_off" to preserve original behaviour.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
---
drivers/leds/trigger/ledtrig-timer.c | 39 +++++++++++++++++++++++++++-
1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/trigger/ledtrig-timer.c b/drivers/leds/trigger/ledtrig-timer.c
index 7c14983781ee..3eadcb0a629a 100644
--- a/drivers/leds/trigger/ledtrig-timer.c
+++ b/drivers/leds/trigger/ledtrig-timer.c
@@ -16,6 +16,11 @@
#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/leds.h>
+#include <linux/reboot.h>
+
+static bool reboot_off;
+module_param(reboot_off, bool, 0444);
+MODULE_PARM_DESC(reboot_off, "Switch LED off on reboot");

static ssize_t led_delay_on_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -97,7 +102,39 @@ static struct led_trigger timer_led_trigger = {
.deactivate = timer_trig_deactivate,
.groups = timer_trig_groups,
};
-module_led_trigger(timer_led_trigger);
+
+static int timer_reboot_notifier(struct notifier_block *nb, unsigned long code,
+ void *unused)
+{
+ led_trigger_unregister(&timer_led_trigger);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block timer_reboot_nb = {
+ .notifier_call = timer_reboot_notifier,
+};
+
+static int __init timer_trig_init(void)
+{
+ int ret;
+
+ ret = led_trigger_register(&timer_led_trigger);
+ if (ret)
+ return ret;
+ if (reboot_off)
+ register_reboot_notifier(&timer_reboot_nb);
+ return 0;
+}
+
+static void __exit timer_trig_exit(void)
+{
+ /* Not afraid of -ENOENT */
+ unregister_reboot_notifier(&timer_reboot_nb);
+ led_trigger_unregister(&timer_led_trigger);
+}
+
+module_init(timer_trig_init);
+module_exit(timer_trig_exit);

MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("Timer LED trigger");
--
2.19.1
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