diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-heartbeat.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-heartbeat.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c new file mode 100644 index 000000000..fea6871d2 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-heartbeat.c @@ -0,0 +1,161 @@ +/* + * LED Heartbeat Trigger + * + * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> + * + * Based on Richard Purdie's ledtrig-timer.c and some arch's + * CONFIG_HEARTBEAT code. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/timer.h> +#include <linux/sched.h> +#include <linux/leds.h> +#include <linux/reboot.h> +#include "../leds.h" + +static int panic_heartbeats; + +struct heartbeat_trig_data { + unsigned int phase; + unsigned int period; + struct timer_list timer; +}; + +static void led_heartbeat_function(unsigned long data) +{ + struct led_classdev *led_cdev = (struct led_classdev *) data; + struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; + unsigned long brightness = LED_OFF; + unsigned long delay = 0; + + if (unlikely(panic_heartbeats)) { + led_set_brightness(led_cdev, LED_OFF); + return; + } + + /* acts like an actual heart beat -- ie thump-thump-pause... */ + switch (heartbeat_data->phase) { + case 0: + /* + * The hyperbolic function below modifies the + * heartbeat period length in dependency of the + * current (1min) load. It goes through the points + * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. + */ + heartbeat_data->period = 300 + + (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); + heartbeat_data->period = + msecs_to_jiffies(heartbeat_data->period); + delay = msecs_to_jiffies(70); + heartbeat_data->phase++; + brightness = led_cdev->max_brightness; + break; + case 1: + delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); + heartbeat_data->phase++; + break; + case 2: + delay = msecs_to_jiffies(70); + heartbeat_data->phase++; + brightness = led_cdev->max_brightness; + break; + default: + delay = heartbeat_data->period - heartbeat_data->period / 4 - + msecs_to_jiffies(70); + heartbeat_data->phase = 0; + break; + } + + led_set_brightness_async(led_cdev, brightness); + mod_timer(&heartbeat_data->timer, jiffies + delay); +} + +static void heartbeat_trig_activate(struct led_classdev *led_cdev) +{ + struct heartbeat_trig_data *heartbeat_data; + + heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); + if (!heartbeat_data) + return; + + led_cdev->trigger_data = heartbeat_data; + setup_timer(&heartbeat_data->timer, + led_heartbeat_function, (unsigned long) led_cdev); + heartbeat_data->phase = 0; + led_heartbeat_function(heartbeat_data->timer.data); + led_cdev->activated = true; +} + +static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) +{ + struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; + + if (led_cdev->activated) { + del_timer_sync(&heartbeat_data->timer); + kfree(heartbeat_data); + led_cdev->activated = false; + } +} + +static struct led_trigger heartbeat_led_trigger = { + .name = "heartbeat", + .activate = heartbeat_trig_activate, + .deactivate = heartbeat_trig_deactivate, +}; + +static int heartbeat_reboot_notifier(struct notifier_block *nb, + unsigned long code, void *unused) +{ + led_trigger_unregister(&heartbeat_led_trigger); + return NOTIFY_DONE; +} + +static int heartbeat_panic_notifier(struct notifier_block *nb, + unsigned long code, void *unused) +{ + panic_heartbeats = 1; + return NOTIFY_DONE; +} + +static struct notifier_block heartbeat_reboot_nb = { + .notifier_call = heartbeat_reboot_notifier, +}; + +static struct notifier_block heartbeat_panic_nb = { + .notifier_call = heartbeat_panic_notifier, +}; + +static int __init heartbeat_trig_init(void) +{ + int rc = led_trigger_register(&heartbeat_led_trigger); + + if (!rc) { + atomic_notifier_chain_register(&panic_notifier_list, + &heartbeat_panic_nb); + register_reboot_notifier(&heartbeat_reboot_nb); + } + return rc; +} + +static void __exit heartbeat_trig_exit(void) +{ + unregister_reboot_notifier(&heartbeat_reboot_nb); + atomic_notifier_chain_unregister(&panic_notifier_list, + &heartbeat_panic_nb); + led_trigger_unregister(&heartbeat_led_trigger); +} + +module_init(heartbeat_trig_init); +module_exit(heartbeat_trig_exit); + +MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); +MODULE_DESCRIPTION("Heartbeat LED trigger"); +MODULE_LICENSE("GPL"); |