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891c668b AN |
1 | /* |
2 | * LED Heartbeat Trigger | |
3 | * | |
4 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
5 | * | |
6 | * Based on Richard Purdie's ledtrig-timer.c and some arch's | |
7 | * CONFIG_HEARTBEAT code. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | * | |
13 | */ | |
14 | #include <linux/module.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/timer.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/leds.h> | |
20 | #include "leds.h" | |
21 | ||
22 | struct heartbeat_trig_data { | |
23 | unsigned int phase; | |
24 | unsigned int period; | |
25 | struct timer_list timer; | |
26 | }; | |
27 | ||
28 | static void led_heartbeat_function(unsigned long data) | |
29 | { | |
30 | struct led_classdev *led_cdev = (struct led_classdev *) data; | |
31 | struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; | |
32 | unsigned long brightness = LED_OFF; | |
33 | unsigned long delay = 0; | |
34 | ||
35 | /* acts like an actual heart beat -- ie thump-thump-pause... */ | |
36 | switch (heartbeat_data->phase) { | |
37 | case 0: | |
38 | /* | |
39 | * The hyperbolic function below modifies the | |
40 | * heartbeat period length in dependency of the | |
41 | * current (1min) load. It goes through the points | |
42 | * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. | |
43 | */ | |
44 | heartbeat_data->period = 300 + | |
45 | (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); | |
46 | heartbeat_data->period = | |
47 | msecs_to_jiffies(heartbeat_data->period); | |
48 | delay = msecs_to_jiffies(70); | |
49 | heartbeat_data->phase++; | |
1bd465e6 | 50 | brightness = led_cdev->max_brightness; |
891c668b AN |
51 | break; |
52 | case 1: | |
53 | delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); | |
54 | heartbeat_data->phase++; | |
55 | break; | |
56 | case 2: | |
57 | delay = msecs_to_jiffies(70); | |
58 | heartbeat_data->phase++; | |
1bd465e6 | 59 | brightness = led_cdev->max_brightness; |
891c668b AN |
60 | break; |
61 | default: | |
62 | delay = heartbeat_data->period - heartbeat_data->period / 4 - | |
63 | msecs_to_jiffies(70); | |
64 | heartbeat_data->phase = 0; | |
65 | break; | |
66 | } | |
67 | ||
68 | led_set_brightness(led_cdev, brightness); | |
69 | mod_timer(&heartbeat_data->timer, jiffies + delay); | |
70 | } | |
71 | ||
72 | static void heartbeat_trig_activate(struct led_classdev *led_cdev) | |
73 | { | |
74 | struct heartbeat_trig_data *heartbeat_data; | |
75 | ||
76 | heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); | |
77 | if (!heartbeat_data) | |
78 | return; | |
79 | ||
80 | led_cdev->trigger_data = heartbeat_data; | |
81 | setup_timer(&heartbeat_data->timer, | |
82 | led_heartbeat_function, (unsigned long) led_cdev); | |
83 | heartbeat_data->phase = 0; | |
84 | led_heartbeat_function(heartbeat_data->timer.data); | |
85 | } | |
86 | ||
87 | static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) | |
88 | { | |
89 | struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; | |
90 | ||
91 | if (heartbeat_data) { | |
92 | del_timer_sync(&heartbeat_data->timer); | |
93 | kfree(heartbeat_data); | |
94 | } | |
95 | } | |
96 | ||
97 | static struct led_trigger heartbeat_led_trigger = { | |
98 | .name = "heartbeat", | |
99 | .activate = heartbeat_trig_activate, | |
100 | .deactivate = heartbeat_trig_deactivate, | |
101 | }; | |
102 | ||
103 | static int __init heartbeat_trig_init(void) | |
104 | { | |
105 | return led_trigger_register(&heartbeat_led_trigger); | |
106 | } | |
107 | ||
108 | static void __exit heartbeat_trig_exit(void) | |
109 | { | |
110 | led_trigger_unregister(&heartbeat_led_trigger); | |
111 | } | |
112 | ||
113 | module_init(heartbeat_trig_init); | |
114 | module_exit(heartbeat_trig_exit); | |
115 | ||
116 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); | |
117 | MODULE_DESCRIPTION("Heartbeat LED trigger"); | |
118 | MODULE_LICENSE("GPL"); |