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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/panic_notifier.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/sched.h>
#include <linux/sched/loadavg.h>
#include <linux/leds.h>
#include <linux/reboot.h>
#include "../leds.h"
static int panic_heartbeats;
struct heartbeat_trig_data {
struct led_classdev *led_cdev;
unsigned int phase;
unsigned int period;
struct timer_list timer;
unsigned int invert;
};
static void led_heartbeat_function(struct timer_list *t)
{
struct heartbeat_trig_data *heartbeat_data =
from_timer(heartbeat_data, t, timer);
struct led_classdev *led_cdev;
unsigned long brightness = LED_OFF;
unsigned long delay = 0;
led_cdev = heartbeat_data->led_cdev;
if (unlikely(panic_heartbeats)) {
led_set_brightness_nosleep(led_cdev, LED_OFF);
return;
}
if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))
led_cdev->blink_brightness = led_cdev->new_blink_brightness;
/* 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++;
if (!heartbeat_data->invert)
brightness = led_cdev->blink_brightness;
break;
case 1:
delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
heartbeat_data->phase++;
if (heartbeat_data->invert)
brightness = led_cdev->blink_brightness;
break;
case 2:
delay = msecs_to_jiffies(70);
heartbeat_data->phase++;
if (!heartbeat_data->invert)
brightness = led_cdev->blink_brightness;
break;
default:
delay = heartbeat_data->period - heartbeat_data->period / 4 -
msecs_to_jiffies(70);
heartbeat_data->phase = 0;
if (heartbeat_data->invert)
brightness = led_cdev->blink_brightness;
break;
}
led_set_brightness_nosleep(led_cdev, brightness);
mod_timer(&heartbeat_data->timer, jiffies + delay);
}
static ssize_t led_invert_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct heartbeat_trig_data *heartbeat_data =
led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n", heartbeat_data->invert);
}
static ssize_t led_invert_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size)
{
struct heartbeat_trig_data *heartbeat_data =
led_trigger_get_drvdata(dev);
unsigned long state;
int ret;
ret = kstrtoul(buf, 0, &state);
if (ret)
return ret;
heartbeat_data->invert = !!state;
return size;
}
static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
static struct attribute *heartbeat_trig_attrs[] = {
&dev_attr_invert.attr,
NULL
};
ATTRIBUTE_GROUPS(heartbeat_trig);
static int 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 -ENOMEM;
led_set_trigger_data(led_cdev, heartbeat_data);
heartbeat_data->led_cdev = led_cdev;
timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);
heartbeat_data->phase = 0;
if (!led_cdev->blink_brightness)
led_cdev->blink_brightness = led_cdev->max_brightness;
led_heartbeat_function(&heartbeat_data->timer);
set_bit(LED_BLINK_SW, &led_cdev->work_flags);
return 0;
}
static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
{
struct heartbeat_trig_data *heartbeat_data =
led_get_trigger_data(led_cdev);
timer_shutdown_sync(&heartbeat_data->timer);
kfree(heartbeat_data);
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
}
static struct led_trigger heartbeat_led_trigger = {
.name = "heartbeat",
.activate = heartbeat_trig_activate,
.deactivate = heartbeat_trig_deactivate,
.groups = heartbeat_trig_groups,
};
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 v2");
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