1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Kernel Panic LED Trigger
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright 2016 Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/kernel.h>
9*4882a593Smuzhiyun #include <linux/init.h>
10*4882a593Smuzhiyun #include <linux/notifier.h>
11*4882a593Smuzhiyun #include <linux/leds.h>
12*4882a593Smuzhiyun #include "../leds.h"
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun static struct led_trigger *trigger;
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun * This is called in a special context by the atomic panic
18*4882a593Smuzhiyun * notifier. This means the trigger can be changed without
19*4882a593Smuzhiyun * worrying about locking.
20*4882a593Smuzhiyun */
led_trigger_set_panic(struct led_classdev * led_cdev)21*4882a593Smuzhiyun static void led_trigger_set_panic(struct led_classdev *led_cdev)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun struct led_trigger *trig;
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun list_for_each_entry(trig, &trigger_list, next_trig) {
26*4882a593Smuzhiyun if (strcmp("panic", trig->name))
27*4882a593Smuzhiyun continue;
28*4882a593Smuzhiyun if (led_cdev->trigger)
29*4882a593Smuzhiyun list_del(&led_cdev->trig_list);
30*4882a593Smuzhiyun list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun /* Avoid the delayed blink path */
33*4882a593Smuzhiyun led_cdev->blink_delay_on = 0;
34*4882a593Smuzhiyun led_cdev->blink_delay_off = 0;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun led_cdev->trigger = trig;
37*4882a593Smuzhiyun if (trig->activate)
38*4882a593Smuzhiyun trig->activate(led_cdev);
39*4882a593Smuzhiyun break;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
led_trigger_panic_notifier(struct notifier_block * nb,unsigned long code,void * unused)43*4882a593Smuzhiyun static int led_trigger_panic_notifier(struct notifier_block *nb,
44*4882a593Smuzhiyun unsigned long code, void *unused)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun struct led_classdev *led_cdev;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun list_for_each_entry(led_cdev, &leds_list, node)
49*4882a593Smuzhiyun if (led_cdev->flags & LED_PANIC_INDICATOR)
50*4882a593Smuzhiyun led_trigger_set_panic(led_cdev);
51*4882a593Smuzhiyun return NOTIFY_DONE;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun static struct notifier_block led_trigger_panic_nb = {
55*4882a593Smuzhiyun .notifier_call = led_trigger_panic_notifier,
56*4882a593Smuzhiyun };
57*4882a593Smuzhiyun
led_panic_blink(int state)58*4882a593Smuzhiyun static long led_panic_blink(int state)
59*4882a593Smuzhiyun {
60*4882a593Smuzhiyun led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
61*4882a593Smuzhiyun return 0;
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
ledtrig_panic_init(void)64*4882a593Smuzhiyun static int __init ledtrig_panic_init(void)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun atomic_notifier_chain_register(&panic_notifier_list,
67*4882a593Smuzhiyun &led_trigger_panic_nb);
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun led_trigger_register_simple("panic", &trigger);
70*4882a593Smuzhiyun panic_blink = led_panic_blink;
71*4882a593Smuzhiyun return 0;
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun device_initcall(ledtrig_panic_init);
74