2 * LED Heartbeat Trigger
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 * Based on Richard Purdie's ledtrig-timer.c and some arch's
7 * CONFIG_HEARTBEAT code.
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.
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>
22 struct heartbeat_trig_data
{
25 struct timer_list timer
;
28 static void led_heartbeat_function(unsigned long data
)
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;
35 /* acts like an actual heart beat -- ie thump-thump-pause... */
36 switch (heartbeat_data
->phase
) {
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.
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
++;
50 brightness
= led_cdev
->max_brightness
;
53 delay
= heartbeat_data
->period
/ 4 - msecs_to_jiffies(70);
54 heartbeat_data
->phase
++;
57 delay
= msecs_to_jiffies(70);
58 heartbeat_data
->phase
++;
59 brightness
= led_cdev
->max_brightness
;
62 delay
= heartbeat_data
->period
- heartbeat_data
->period
/ 4 -
64 heartbeat_data
->phase
= 0;
68 led_set_brightness(led_cdev
, brightness
);
69 mod_timer(&heartbeat_data
->timer
, jiffies
+ delay
);
72 static void heartbeat_trig_activate(struct led_classdev
*led_cdev
)
74 struct heartbeat_trig_data
*heartbeat_data
;
76 heartbeat_data
= kzalloc(sizeof(*heartbeat_data
), GFP_KERNEL
);
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
);
87 static void heartbeat_trig_deactivate(struct led_classdev
*led_cdev
)
89 struct heartbeat_trig_data
*heartbeat_data
= led_cdev
->trigger_data
;
92 del_timer_sync(&heartbeat_data
->timer
);
93 kfree(heartbeat_data
);
97 static struct led_trigger heartbeat_led_trigger
= {
99 .activate
= heartbeat_trig_activate
,
100 .deactivate
= heartbeat_trig_deactivate
,
103 static int __init
heartbeat_trig_init(void)
105 return led_trigger_register(&heartbeat_led_trigger
);
108 static void __exit
heartbeat_trig_exit(void)
110 led_trigger_unregister(&heartbeat_led_trigger
);
113 module_init(heartbeat_trig_init
);
114 module_exit(heartbeat_trig_exit
);
116 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
117 MODULE_DESCRIPTION("Heartbeat LED trigger");
118 MODULE_LICENSE("GPL");