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132e9306 RG |
1 | /* |
2 | * Backlight emulation LED trigger | |
3 | * | |
4 | * Copyright 2008 (C) Rodolfo Giometti <giometti@linux.it> | |
5 | * Copyright 2008 (C) Eurotech S.p.A. <info@eurotech.it> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/kernel.h> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
132e9306 RG |
16 | #include <linux/init.h> |
17 | #include <linux/fb.h> | |
18 | #include <linux/leds.h> | |
19 | #include "leds.h" | |
20 | ||
21 | #define BLANK 1 | |
22 | #define UNBLANK 0 | |
23 | ||
24 | struct bl_trig_notifier { | |
25 | struct led_classdev *led; | |
26 | int brightness; | |
27 | int old_status; | |
28 | struct notifier_block notifier; | |
29 | }; | |
30 | ||
31 | static int fb_notifier_callback(struct notifier_block *p, | |
32 | unsigned long event, void *data) | |
33 | { | |
34 | struct bl_trig_notifier *n = container_of(p, | |
35 | struct bl_trig_notifier, notifier); | |
36 | struct led_classdev *led = n->led; | |
37 | struct fb_event *fb_event = data; | |
38 | int *blank = fb_event->data; | |
39 | ||
40 | switch (event) { | |
41 | case FB_EVENT_BLANK : | |
42 | if (*blank && n->old_status == UNBLANK) { | |
43 | n->brightness = led->brightness; | |
44 | led_set_brightness(led, LED_OFF); | |
45 | n->old_status = BLANK; | |
46 | } else if (!*blank && n->old_status == BLANK) { | |
47 | led_set_brightness(led, n->brightness); | |
48 | n->old_status = UNBLANK; | |
49 | } | |
50 | break; | |
51 | } | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | static void bl_trig_activate(struct led_classdev *led) | |
57 | { | |
58 | int ret; | |
59 | ||
60 | struct bl_trig_notifier *n; | |
61 | ||
62 | n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL); | |
63 | led->trigger_data = n; | |
64 | if (!n) { | |
65 | dev_err(led->dev, "unable to allocate backlight trigger\n"); | |
66 | return; | |
67 | } | |
68 | ||
69 | n->led = led; | |
70 | n->brightness = led->brightness; | |
71 | n->old_status = UNBLANK; | |
72 | n->notifier.notifier_call = fb_notifier_callback; | |
73 | ||
74 | ret = fb_register_client(&n->notifier); | |
75 | if (ret) | |
76 | dev_err(led->dev, "unable to register backlight trigger\n"); | |
77 | } | |
78 | ||
79 | static void bl_trig_deactivate(struct led_classdev *led) | |
80 | { | |
81 | struct bl_trig_notifier *n = | |
82 | (struct bl_trig_notifier *) led->trigger_data; | |
83 | ||
84 | if (n) { | |
85 | fb_unregister_client(&n->notifier); | |
86 | kfree(n); | |
87 | } | |
88 | } | |
89 | ||
90 | static struct led_trigger bl_led_trigger = { | |
91 | .name = "backlight", | |
92 | .activate = bl_trig_activate, | |
93 | .deactivate = bl_trig_deactivate | |
94 | }; | |
95 | ||
96 | static int __init bl_trig_init(void) | |
97 | { | |
98 | return led_trigger_register(&bl_led_trigger); | |
99 | } | |
100 | ||
101 | static void __exit bl_trig_exit(void) | |
102 | { | |
103 | led_trigger_unregister(&bl_led_trigger); | |
104 | } | |
105 | ||
106 | module_init(bl_trig_init); | |
107 | module_exit(bl_trig_exit); | |
108 | ||
109 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
110 | MODULE_DESCRIPTION("Backlight emulation LED trigger"); | |
111 | MODULE_LICENSE("GPL v2"); |