[PATCH v4] leds: heartbeat: stop on shutdown, reboot or panic

[Alexander Holler <holler@ahsoftware.de>]

A halted kernel should not show a heartbeat.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
---
 drivers/leds/ledtrig-heartbeat.c |   27 ++++++++++++++++++++++++++-
 1 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
index 759c0bb..31c234c 100644
--- a/drivers/leds/ledtrig-heartbeat.c
+++ b/drivers/leds/ledtrig-heartbeat.c
@@ -18,6 +18,7 @@
 #include <linux/timer.h>
 #include <linux/sched.h>
 #include <linux/leds.h>
+#include <linux/reboot.h>
 #include "leds.h"
 
 struct heartbeat_trig_data {
@@ -101,13 +102,37 @@ static struct led_trigger heartbeat_led_trigger = {
 	.deactivate = heartbeat_trig_deactivate,
 };
 
+static int heartbeat_reboot_notifier(struct notifier_block *nb,
+				     unsigned long code, void *unused)
+{
+	led_trigger_unregister(&heartbeat_led_trigger);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block heartbeat_reboot_nb = {
+	.notifier_call = heartbeat_reboot_notifier,
+};
+
+static struct notifier_block heartbeat_panic_nb = {
+	.notifier_call = heartbeat_reboot_notifier,
+};
+
 static int __init heartbeat_trig_init(void)
 {
-	return led_trigger_register(&heartbeat_led_trigger);
+	int rc = led_trigger_register(&heartbeat_led_trigger);
+	if (!rc) {
+		atomic_notifier_chain_register(&panic_notifier_list,
+					       &heartbeat_panic_nb);
+		register_reboot_notifier(&heartbeat_reboot_nb);
+	}
+	return rc;
 }
 
 static void __exit heartbeat_trig_exit(void)
 {
+	unregister_reboot_notifier(&heartbeat_reboot_nb);
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &heartbeat_panic_nb);
 	led_trigger_unregister(&heartbeat_led_trigger);
 }
 
-- 
1.7.6.5