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916fe619 EG |
1 | /* |
2 | * Kernel Panic LED Trigger | |
3 | * | |
4 | * Copyright 2016 Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/init.h> | |
ba93cdce | 14 | #include <linux/notifier.h> |
916fe619 | 15 | #include <linux/leds.h> |
ba93cdce | 16 | #include "../leds.h" |
916fe619 EG |
17 | |
18 | static struct led_trigger *trigger; | |
19 | ||
ba93cdce EG |
20 | /* |
21 | * This is called in a special context by the atomic panic | |
22 | * notifier. This means the trigger can be changed without | |
23 | * worrying about locking. | |
24 | */ | |
25 | static void led_trigger_set_panic(struct led_classdev *led_cdev) | |
26 | { | |
27 | struct led_trigger *trig; | |
28 | ||
29 | list_for_each_entry(trig, &trigger_list, next_trig) { | |
30 | if (strcmp("panic", trig->name)) | |
31 | continue; | |
32 | if (led_cdev->trigger) | |
33 | list_del(&led_cdev->trig_list); | |
34 | list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); | |
35 | ||
36 | /* Avoid the delayed blink path */ | |
37 | led_cdev->blink_delay_on = 0; | |
38 | led_cdev->blink_delay_off = 0; | |
39 | ||
40 | led_cdev->trigger = trig; | |
41 | if (trig->activate) | |
42 | trig->activate(led_cdev); | |
43 | break; | |
44 | } | |
45 | } | |
46 | ||
47 | static int led_trigger_panic_notifier(struct notifier_block *nb, | |
48 | unsigned long code, void *unused) | |
49 | { | |
50 | struct led_classdev *led_cdev; | |
51 | ||
52 | list_for_each_entry(led_cdev, &leds_list, node) | |
53 | if (led_cdev->flags & LED_PANIC_INDICATOR) | |
54 | led_trigger_set_panic(led_cdev); | |
55 | return NOTIFY_DONE; | |
56 | } | |
57 | ||
58 | static struct notifier_block led_trigger_panic_nb = { | |
59 | .notifier_call = led_trigger_panic_notifier, | |
60 | }; | |
61 | ||
916fe619 EG |
62 | static long led_panic_blink(int state) |
63 | { | |
64 | led_trigger_event(trigger, state ? LED_FULL : LED_OFF); | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static int __init ledtrig_panic_init(void) | |
69 | { | |
ba93cdce EG |
70 | atomic_notifier_chain_register(&panic_notifier_list, |
71 | &led_trigger_panic_nb); | |
72 | ||
916fe619 EG |
73 | led_trigger_register_simple("panic", &trigger); |
74 | panic_blink = led_panic_blink; | |
75 | return 0; | |
76 | } | |
77 | device_initcall(ledtrig_panic_init); |