![Uwe Kleine-König](/assets/img/avatar_default.png)
Given that activating a trigger can fail, let the callback return an indication. This prevents to have a trigger active according to the "trigger" sysfs attribute but not functional. All users are changed accordingly to return 0 for now. There is no intended change in behaviour. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
219 lines
5.7 KiB
C
219 lines
5.7 KiB
C
/*
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* LED Heartbeat Trigger
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*
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* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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*
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* Based on Richard Purdie's ledtrig-timer.c and some arch's
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* CONFIG_HEARTBEAT code.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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#include <linux/sched.h>
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#include <linux/sched/loadavg.h>
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#include <linux/leds.h>
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#include <linux/reboot.h>
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#include "../leds.h"
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static int panic_heartbeats;
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struct heartbeat_trig_data {
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struct led_classdev *led_cdev;
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unsigned int phase;
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unsigned int period;
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struct timer_list timer;
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unsigned int invert;
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};
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static void led_heartbeat_function(struct timer_list *t)
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{
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struct heartbeat_trig_data *heartbeat_data =
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from_timer(heartbeat_data, t, timer);
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struct led_classdev *led_cdev;
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unsigned long brightness = LED_OFF;
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unsigned long delay = 0;
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led_cdev = heartbeat_data->led_cdev;
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if (unlikely(panic_heartbeats)) {
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led_set_brightness_nosleep(led_cdev, LED_OFF);
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return;
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}
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if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))
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led_cdev->blink_brightness = led_cdev->new_blink_brightness;
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/* acts like an actual heart beat -- ie thump-thump-pause... */
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switch (heartbeat_data->phase) {
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case 0:
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/*
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* The hyperbolic function below modifies the
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* heartbeat period length in dependency of the
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* current (1min) load. It goes through the points
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* f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
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*/
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heartbeat_data->period = 300 +
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(6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
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heartbeat_data->period =
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msecs_to_jiffies(heartbeat_data->period);
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delay = msecs_to_jiffies(70);
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heartbeat_data->phase++;
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if (!heartbeat_data->invert)
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brightness = led_cdev->blink_brightness;
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break;
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case 1:
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delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
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heartbeat_data->phase++;
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if (heartbeat_data->invert)
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brightness = led_cdev->blink_brightness;
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break;
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case 2:
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delay = msecs_to_jiffies(70);
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heartbeat_data->phase++;
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if (!heartbeat_data->invert)
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brightness = led_cdev->blink_brightness;
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break;
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default:
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delay = heartbeat_data->period - heartbeat_data->period / 4 -
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msecs_to_jiffies(70);
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heartbeat_data->phase = 0;
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if (heartbeat_data->invert)
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brightness = led_cdev->blink_brightness;
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break;
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}
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led_set_brightness_nosleep(led_cdev, brightness);
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mod_timer(&heartbeat_data->timer, jiffies + delay);
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}
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static ssize_t led_invert_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
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return sprintf(buf, "%u\n", heartbeat_data->invert);
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}
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static ssize_t led_invert_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
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unsigned long state;
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int ret;
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ret = kstrtoul(buf, 0, &state);
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if (ret)
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return ret;
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heartbeat_data->invert = !!state;
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return size;
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}
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static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
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static int heartbeat_trig_activate(struct led_classdev *led_cdev)
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{
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struct heartbeat_trig_data *heartbeat_data;
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int rc;
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heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
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if (!heartbeat_data)
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return 0;
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led_cdev->trigger_data = heartbeat_data;
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heartbeat_data->led_cdev = led_cdev;
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rc = device_create_file(led_cdev->dev, &dev_attr_invert);
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if (rc) {
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kfree(led_cdev->trigger_data);
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return 0;
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}
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timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);
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heartbeat_data->phase = 0;
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if (!led_cdev->blink_brightness)
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led_cdev->blink_brightness = led_cdev->max_brightness;
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led_heartbeat_function(&heartbeat_data->timer);
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set_bit(LED_BLINK_SW, &led_cdev->work_flags);
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led_cdev->activated = true;
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return 0;
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}
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static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
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{
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struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
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if (led_cdev->activated) {
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del_timer_sync(&heartbeat_data->timer);
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device_remove_file(led_cdev->dev, &dev_attr_invert);
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kfree(heartbeat_data);
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clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
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led_cdev->activated = false;
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}
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}
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static struct led_trigger heartbeat_led_trigger = {
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.name = "heartbeat",
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.activate = heartbeat_trig_activate,
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.deactivate = heartbeat_trig_deactivate,
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};
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static int heartbeat_reboot_notifier(struct notifier_block *nb,
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unsigned long code, void *unused)
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{
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led_trigger_unregister(&heartbeat_led_trigger);
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return NOTIFY_DONE;
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}
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static int heartbeat_panic_notifier(struct notifier_block *nb,
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unsigned long code, void *unused)
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{
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panic_heartbeats = 1;
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return NOTIFY_DONE;
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}
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static struct notifier_block heartbeat_reboot_nb = {
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.notifier_call = heartbeat_reboot_notifier,
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};
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static struct notifier_block heartbeat_panic_nb = {
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.notifier_call = heartbeat_panic_notifier,
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};
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static int __init heartbeat_trig_init(void)
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{
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int rc = led_trigger_register(&heartbeat_led_trigger);
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if (!rc) {
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atomic_notifier_chain_register(&panic_notifier_list,
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&heartbeat_panic_nb);
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register_reboot_notifier(&heartbeat_reboot_nb);
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}
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return rc;
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}
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static void __exit heartbeat_trig_exit(void)
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{
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unregister_reboot_notifier(&heartbeat_reboot_nb);
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atomic_notifier_chain_unregister(&panic_notifier_list,
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&heartbeat_panic_nb);
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led_trigger_unregister(&heartbeat_led_trigger);
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}
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module_init(heartbeat_trig_init);
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module_exit(heartbeat_trig_exit);
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MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
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MODULE_DESCRIPTION("Heartbeat LED trigger");
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MODULE_LICENSE("GPL v2");
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