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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> |
15 | #include <linux/slab.h> |
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"); |
112 |
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Tags:
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od-2011-09-18
v2.6.34-rc5
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