hwmon: (adt7411) add MODULE_DEVICE_TABLE
[linux-2.6.git] / drivers / leds / ledtrig-heartbeat.c
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/slab.h>
18 #include <linux/timer.h>
19 #include <linux/sched.h>
20 #include <linux/leds.h>
21 #include "leds.h"
22
23 struct heartbeat_trig_data {
24         unsigned int phase;
25         unsigned int period;
26         struct timer_list timer;
27 };
28
29 static void led_heartbeat_function(unsigned long data)
30 {
31         struct led_classdev *led_cdev = (struct led_classdev *) data;
32         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
33         unsigned long brightness = LED_OFF;
34         unsigned long delay = 0;
35
36         /* acts like an actual heart beat -- ie thump-thump-pause... */
37         switch (heartbeat_data->phase) {
38         case 0:
39                 /*
40                  * The hyperbolic function below modifies the
41                  * heartbeat period length in dependency of the
42                  * current (1min) load. It goes through the points
43                  * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
44                  */
45                 heartbeat_data->period = 300 +
46                         (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
47                 heartbeat_data->period =
48                         msecs_to_jiffies(heartbeat_data->period);
49                 delay = msecs_to_jiffies(70);
50                 heartbeat_data->phase++;
51                 brightness = led_cdev->max_brightness;
52                 break;
53         case 1:
54                 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
55                 heartbeat_data->phase++;
56                 break;
57         case 2:
58                 delay = msecs_to_jiffies(70);
59                 heartbeat_data->phase++;
60                 brightness = led_cdev->max_brightness;
61                 break;
62         default:
63                 delay = heartbeat_data->period - heartbeat_data->period / 4 -
64                         msecs_to_jiffies(70);
65                 heartbeat_data->phase = 0;
66                 break;
67         }
68
69         led_set_brightness(led_cdev, brightness);
70         mod_timer(&heartbeat_data->timer, jiffies + delay);
71 }
72
73 static void heartbeat_trig_activate(struct led_classdev *led_cdev)
74 {
75         struct heartbeat_trig_data *heartbeat_data;
76
77         heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
78         if (!heartbeat_data)
79                 return;
80
81         led_cdev->trigger_data = heartbeat_data;
82         setup_timer(&heartbeat_data->timer,
83                     led_heartbeat_function, (unsigned long) led_cdev);
84         heartbeat_data->phase = 0;
85         led_heartbeat_function(heartbeat_data->timer.data);
86 }
87
88 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
89 {
90         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
91
92         if (heartbeat_data) {
93                 del_timer_sync(&heartbeat_data->timer);
94                 kfree(heartbeat_data);
95         }
96 }
97
98 static struct led_trigger heartbeat_led_trigger = {
99         .name     = "heartbeat",
100         .activate = heartbeat_trig_activate,
101         .deactivate = heartbeat_trig_deactivate,
102 };
103
104 static int __init heartbeat_trig_init(void)
105 {
106         return led_trigger_register(&heartbeat_led_trigger);
107 }
108
109 static void __exit heartbeat_trig_exit(void)
110 {
111         led_trigger_unregister(&heartbeat_led_trigger);
112 }
113
114 module_init(heartbeat_trig_init);
115 module_exit(heartbeat_trig_exit);
116
117 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
118 MODULE_DESCRIPTION("Heartbeat LED trigger");
119 MODULE_LICENSE("GPL");