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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * LED Heartbeat Trigger4 *5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>6 *7 * Based on Richard Purdie's ledtrig-timer.c and some arch's8 * CONFIG_HEARTBEAT code.9 */10 11#include <linux/module.h>12#include <linux/kernel.h>13#include <linux/init.h>14#include <linux/panic_notifier.h>15#include <linux/slab.h>16#include <linux/timer.h>17#include <linux/sched.h>18#include <linux/sched/loadavg.h>19#include <linux/leds.h>20#include <linux/reboot.h>21#include "../leds.h"22 23static int panic_heartbeats;24 25struct heartbeat_trig_data {26 struct led_classdev *led_cdev;27 unsigned int phase;28 unsigned int period;29 struct timer_list timer;30 unsigned int invert;31};32 33static void led_heartbeat_function(struct timer_list *t)34{35 struct heartbeat_trig_data *heartbeat_data =36 from_timer(heartbeat_data, t, timer);37 struct led_classdev *led_cdev;38 unsigned long brightness = LED_OFF;39 unsigned long delay = 0;40 41 led_cdev = heartbeat_data->led_cdev;42 43 if (unlikely(panic_heartbeats)) {44 led_set_brightness_nosleep(led_cdev, LED_OFF);45 return;46 }47 48 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))49 led_cdev->blink_brightness = led_cdev->new_blink_brightness;50 51 /* acts like an actual heart beat -- ie thump-thump-pause... */52 switch (heartbeat_data->phase) {53 case 0:54 /*55 * The hyperbolic function below modifies the56 * heartbeat period length in dependency of the57 * current (1min) load. It goes through the points58 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.59 */60 heartbeat_data->period = 300 +61 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));62 heartbeat_data->period =63 msecs_to_jiffies(heartbeat_data->period);64 delay = msecs_to_jiffies(70);65 heartbeat_data->phase++;66 if (!heartbeat_data->invert)67 brightness = led_cdev->blink_brightness;68 break;69 case 1:70 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);71 heartbeat_data->phase++;72 if (heartbeat_data->invert)73 brightness = led_cdev->blink_brightness;74 break;75 case 2:76 delay = msecs_to_jiffies(70);77 heartbeat_data->phase++;78 if (!heartbeat_data->invert)79 brightness = led_cdev->blink_brightness;80 break;81 default:82 delay = heartbeat_data->period - heartbeat_data->period / 4 -83 msecs_to_jiffies(70);84 heartbeat_data->phase = 0;85 if (heartbeat_data->invert)86 brightness = led_cdev->blink_brightness;87 break;88 }89 90 led_set_brightness_nosleep(led_cdev, brightness);91 mod_timer(&heartbeat_data->timer, jiffies + delay);92}93 94static ssize_t led_invert_show(struct device *dev,95 struct device_attribute *attr, char *buf)96{97 struct heartbeat_trig_data *heartbeat_data =98 led_trigger_get_drvdata(dev);99 100 return sprintf(buf, "%u\n", heartbeat_data->invert);101}102 103static ssize_t led_invert_store(struct device *dev,104 struct device_attribute *attr, const char *buf, size_t size)105{106 struct heartbeat_trig_data *heartbeat_data =107 led_trigger_get_drvdata(dev);108 unsigned long state;109 int ret;110 111 ret = kstrtoul(buf, 0, &state);112 if (ret)113 return ret;114 115 heartbeat_data->invert = !!state;116 117 return size;118}119 120static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);121 122static struct attribute *heartbeat_trig_attrs[] = {123 &dev_attr_invert.attr,124 NULL125};126ATTRIBUTE_GROUPS(heartbeat_trig);127 128static int heartbeat_trig_activate(struct led_classdev *led_cdev)129{130 struct heartbeat_trig_data *heartbeat_data;131 132 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);133 if (!heartbeat_data)134 return -ENOMEM;135 136 led_set_trigger_data(led_cdev, heartbeat_data);137 heartbeat_data->led_cdev = led_cdev;138 139 timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);140 heartbeat_data->phase = 0;141 if (!led_cdev->blink_brightness)142 led_cdev->blink_brightness = led_cdev->max_brightness;143 led_heartbeat_function(&heartbeat_data->timer);144 set_bit(LED_BLINK_SW, &led_cdev->work_flags);145 146 return 0;147}148 149static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)150{151 struct heartbeat_trig_data *heartbeat_data =152 led_get_trigger_data(led_cdev);153 154 timer_shutdown_sync(&heartbeat_data->timer);155 kfree(heartbeat_data);156 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);157}158 159static struct led_trigger heartbeat_led_trigger = {160 .name = "heartbeat",161 .activate = heartbeat_trig_activate,162 .deactivate = heartbeat_trig_deactivate,163 .groups = heartbeat_trig_groups,164};165 166static int heartbeat_reboot_notifier(struct notifier_block *nb,167 unsigned long code, void *unused)168{169 led_trigger_unregister(&heartbeat_led_trigger);170 return NOTIFY_DONE;171}172 173static int heartbeat_panic_notifier(struct notifier_block *nb,174 unsigned long code, void *unused)175{176 panic_heartbeats = 1;177 return NOTIFY_DONE;178}179 180static struct notifier_block heartbeat_reboot_nb = {181 .notifier_call = heartbeat_reboot_notifier,182};183 184static struct notifier_block heartbeat_panic_nb = {185 .notifier_call = heartbeat_panic_notifier,186};187 188static int __init heartbeat_trig_init(void)189{190 int rc = led_trigger_register(&heartbeat_led_trigger);191 192 if (!rc) {193 atomic_notifier_chain_register(&panic_notifier_list,194 &heartbeat_panic_nb);195 register_reboot_notifier(&heartbeat_reboot_nb);196 }197 return rc;198}199 200static void __exit heartbeat_trig_exit(void)201{202 unregister_reboot_notifier(&heartbeat_reboot_nb);203 atomic_notifier_chain_unregister(&panic_notifier_list,204 &heartbeat_panic_nb);205 led_trigger_unregister(&heartbeat_led_trigger);206}207 208module_init(heartbeat_trig_init);209module_exit(heartbeat_trig_exit);210 211MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");212MODULE_DESCRIPTION("Heartbeat LED trigger");213MODULE_LICENSE("GPL v2");214