Rodolfo Giometti | 132e930 | 2008-10-13 09:25:24 +0100 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 15 | #include <linux/slab.h> |
Rodolfo Giometti | 132e930 | 2008-10-13 09:25:24 +0100 | [diff] [blame] | 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"); |