// 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){	if (led_cdev->trigger)		list_del(&led_cdev->trig_list);	list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs); 	/* Avoid the delayed blink path */	led_cdev->blink_delay_on = 0;	led_cdev->blink_delay_off = 0; 	led_cdev->trigger = trigger;} 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);