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// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel Panic LED Trigger
*
* Copyright 2016 Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/panic_notifier.h>
#include <linux/leds.h>
#include "../leds.h"
static struct led_trigger *trigger;
/*
* This is called in a special context by the atomic panic
* notifier. This means the trigger can be changed without
* worrying about locking.
*/
static void led_trigger_set_panic(struct led_classdev *led_cdev)
{
struct led_trigger *trig;
list_for_each_entry(trig, &trigger_list, next_trig) {
if (strcmp("panic", trig->name))
continue;
if (led_cdev->trigger)
list_del(&led_cdev->trig_list);
list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
/* Avoid the delayed blink path */
led_cdev->blink_delay_on = 0;
led_cdev->blink_delay_off = 0;
led_cdev->trigger = trig;
if (trig->activate)
trig->activate(led_cdev);
break;
}
}
static int led_trigger_panic_notifier(struct notifier_block *nb,
unsigned long code, void *unused)
{
struct led_classdev *led_cdev;
list_for_each_entry(led_cdev, &leds_list, node)
if (led_cdev->flags & LED_PANIC_INDICATOR)
led_trigger_set_panic(led_cdev);
return NOTIFY_DONE;
}
static struct notifier_block led_trigger_panic_nb = {
.notifier_call = led_trigger_panic_notifier,
};
static long led_panic_blink(int state)
{
led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
return 0;
}
static int __init ledtrig_panic_init(void)
{
led_trigger_register_simple("panic", &trigger);
if (!trigger)
return -ENOMEM;
atomic_notifier_chain_register(&panic_notifier_list,
&led_trigger_panic_nb);
panic_blink = led_panic_blink;
return 0;
}
device_initcall(ledtrig_panic_init);
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