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/slab.h>
18 #include <linux/timer.h>
19 #include <linux/sched.h>
20 #include <linux/leds.h>
21 #include <linux/reboot.h>
24 struct heartbeat_trig_data
{
27 struct timer_list timer
;
30 static void led_heartbeat_function(unsigned long data
)
32 struct led_classdev
*led_cdev
= (struct led_classdev
*) data
;
33 struct heartbeat_trig_data
*heartbeat_data
= led_cdev
->trigger_data
;
34 unsigned long brightness
= LED_OFF
;
35 unsigned long delay
= 0;
37 /* acts like an actual heart beat -- ie thump-thump-pause... */
38 switch (heartbeat_data
->phase
) {
41 * The hyperbolic function below modifies the
42 * heartbeat period length in dependency of the
43 * current (1min) load. It goes through the points
44 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
46 heartbeat_data
->period
= 300 +
47 (6720 << FSHIFT
) / (5 * avenrun
[0] + (7 << FSHIFT
));
48 heartbeat_data
->period
=
49 msecs_to_jiffies(heartbeat_data
->period
);
50 delay
= msecs_to_jiffies(70);
51 heartbeat_data
->phase
++;
52 brightness
= led_cdev
->max_brightness
;
55 delay
= heartbeat_data
->period
/ 4 - msecs_to_jiffies(70);
56 heartbeat_data
->phase
++;
59 delay
= msecs_to_jiffies(70);
60 heartbeat_data
->phase
++;
61 brightness
= led_cdev
->max_brightness
;
64 delay
= heartbeat_data
->period
- heartbeat_data
->period
/ 4 -
66 heartbeat_data
->phase
= 0;
70 led_set_brightness(led_cdev
, brightness
);
71 mod_timer(&heartbeat_data
->timer
, jiffies
+ delay
);
74 static void heartbeat_trig_activate(struct led_classdev
*led_cdev
)
76 struct heartbeat_trig_data
*heartbeat_data
;
78 heartbeat_data
= kzalloc(sizeof(*heartbeat_data
), GFP_KERNEL
);
82 led_cdev
->trigger_data
= heartbeat_data
;
83 setup_timer(&heartbeat_data
->timer
,
84 led_heartbeat_function
, (unsigned long) led_cdev
);
85 heartbeat_data
->phase
= 0;
86 led_heartbeat_function(heartbeat_data
->timer
.data
);
87 led_cdev
->activated
= true;
90 static void heartbeat_trig_deactivate(struct led_classdev
*led_cdev
)
92 struct heartbeat_trig_data
*heartbeat_data
= led_cdev
->trigger_data
;
94 if (led_cdev
->activated
) {
95 del_timer_sync(&heartbeat_data
->timer
);
96 kfree(heartbeat_data
);
97 led_cdev
->activated
= false;
101 static struct led_trigger heartbeat_led_trigger
= {
103 .activate
= heartbeat_trig_activate
,
104 .deactivate
= heartbeat_trig_deactivate
,
107 static int heartbeat_reboot_notifier(struct notifier_block
*nb
,
108 unsigned long code
, void *unused
)
110 led_trigger_unregister(&heartbeat_led_trigger
);
114 static struct notifier_block heartbeat_reboot_nb
= {
115 .notifier_call
= heartbeat_reboot_notifier
,
118 static struct notifier_block heartbeat_panic_nb
= {
119 .notifier_call
= heartbeat_reboot_notifier
,
122 static int __init
heartbeat_trig_init(void)
124 int rc
= led_trigger_register(&heartbeat_led_trigger
);
127 atomic_notifier_chain_register(&panic_notifier_list
,
128 &heartbeat_panic_nb
);
129 register_reboot_notifier(&heartbeat_reboot_nb
);
134 static void __exit
heartbeat_trig_exit(void)
136 unregister_reboot_notifier(&heartbeat_reboot_nb
);
137 atomic_notifier_chain_unregister(&panic_notifier_list
,
138 &heartbeat_panic_nb
);
139 led_trigger_unregister(&heartbeat_led_trigger
);
142 module_init(heartbeat_trig_init
);
143 module_exit(heartbeat_trig_exit
);
145 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
146 MODULE_DESCRIPTION("Heartbeat LED trigger");
147 MODULE_LICENSE("GPL");