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