1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LED Heartbeat Trigger 4 * 5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 6 * 7 * Based on Richard Purdie's ledtrig-timer.c and some arch's 8 * CONFIG_HEARTBEAT code. 9 */ 10 11 #include <linux/module.h> 12 #include <linux/kernel.h> 13 #include <linux/init.h> 14 #include <linux/slab.h> 15 #include <linux/timer.h> 16 #include <linux/sched.h> 17 #include <linux/sched/loadavg.h> 18 #include <linux/leds.h> 19 #include <linux/reboot.h> 20 #include "../leds.h" 21 22 static int panic_heartbeats; 23 24 struct heartbeat_trig_data { 25 struct led_classdev *led_cdev; 26 unsigned int phase; 27 unsigned int period; 28 struct timer_list timer; 29 unsigned int invert; 30 }; 31 32 static void led_heartbeat_function(struct timer_list *t) 33 { 34 struct heartbeat_trig_data *heartbeat_data = 35 from_timer(heartbeat_data, t, timer); 36 struct led_classdev *led_cdev; 37 unsigned long brightness = LED_OFF; 38 unsigned long delay = 0; 39 40 led_cdev = heartbeat_data->led_cdev; 41 42 if (unlikely(panic_heartbeats)) { 43 led_set_brightness_nosleep(led_cdev, LED_OFF); 44 return; 45 } 46 47 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags)) 48 led_cdev->blink_brightness = led_cdev->new_blink_brightness; 49 50 /* acts like an actual heart beat -- ie thump-thump-pause... */ 51 switch (heartbeat_data->phase) { 52 case 0: 53 /* 54 * The hyperbolic function below modifies the 55 * heartbeat period length in dependency of the 56 * current (1min) load. It goes through the points 57 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 58 */ 59 heartbeat_data->period = 300 + 60 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 61 heartbeat_data->period = 62 msecs_to_jiffies(heartbeat_data->period); 63 delay = msecs_to_jiffies(70); 64 heartbeat_data->phase++; 65 if (!heartbeat_data->invert) 66 brightness = led_cdev->blink_brightness; 67 break; 68 case 1: 69 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 70 heartbeat_data->phase++; 71 if (heartbeat_data->invert) 72 brightness = led_cdev->blink_brightness; 73 break; 74 case 2: 75 delay = msecs_to_jiffies(70); 76 heartbeat_data->phase++; 77 if (!heartbeat_data->invert) 78 brightness = led_cdev->blink_brightness; 79 break; 80 default: 81 delay = heartbeat_data->period - heartbeat_data->period / 4 - 82 msecs_to_jiffies(70); 83 heartbeat_data->phase = 0; 84 if (heartbeat_data->invert) 85 brightness = led_cdev->blink_brightness; 86 break; 87 } 88 89 led_set_brightness_nosleep(led_cdev, brightness); 90 mod_timer(&heartbeat_data->timer, jiffies + delay); 91 } 92 93 static ssize_t led_invert_show(struct device *dev, 94 struct device_attribute *attr, char *buf) 95 { 96 struct heartbeat_trig_data *heartbeat_data = 97 led_trigger_get_drvdata(dev); 98 99 return sprintf(buf, "%u\n", heartbeat_data->invert); 100 } 101 102 static ssize_t led_invert_store(struct device *dev, 103 struct device_attribute *attr, const char *buf, size_t size) 104 { 105 struct heartbeat_trig_data *heartbeat_data = 106 led_trigger_get_drvdata(dev); 107 unsigned long state; 108 int ret; 109 110 ret = kstrtoul(buf, 0, &state); 111 if (ret) 112 return ret; 113 114 heartbeat_data->invert = !!state; 115 116 return size; 117 } 118 119 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 120 121 static struct attribute *heartbeat_trig_attrs[] = { 122 &dev_attr_invert.attr, 123 NULL 124 }; 125 ATTRIBUTE_GROUPS(heartbeat_trig); 126 127 static int heartbeat_trig_activate(struct led_classdev *led_cdev) 128 { 129 struct heartbeat_trig_data *heartbeat_data; 130 131 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 132 if (!heartbeat_data) 133 return -ENOMEM; 134 135 led_set_trigger_data(led_cdev, heartbeat_data); 136 heartbeat_data->led_cdev = led_cdev; 137 138 timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0); 139 heartbeat_data->phase = 0; 140 if (!led_cdev->blink_brightness) 141 led_cdev->blink_brightness = led_cdev->max_brightness; 142 led_heartbeat_function(&heartbeat_data->timer); 143 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 144 145 return 0; 146 } 147 148 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 149 { 150 struct heartbeat_trig_data *heartbeat_data = 151 led_get_trigger_data(led_cdev); 152 153 del_timer_sync(&heartbeat_data->timer); 154 kfree(heartbeat_data); 155 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 156 } 157 158 static struct led_trigger heartbeat_led_trigger = { 159 .name = "heartbeat", 160 .activate = heartbeat_trig_activate, 161 .deactivate = heartbeat_trig_deactivate, 162 .groups = heartbeat_trig_groups, 163 }; 164 165 static int heartbeat_reboot_notifier(struct notifier_block *nb, 166 unsigned long code, void *unused) 167 { 168 led_trigger_unregister(&heartbeat_led_trigger); 169 return NOTIFY_DONE; 170 } 171 172 static int heartbeat_panic_notifier(struct notifier_block *nb, 173 unsigned long code, void *unused) 174 { 175 panic_heartbeats = 1; 176 return NOTIFY_DONE; 177 } 178 179 static struct notifier_block heartbeat_reboot_nb = { 180 .notifier_call = heartbeat_reboot_notifier, 181 }; 182 183 static struct notifier_block heartbeat_panic_nb = { 184 .notifier_call = heartbeat_panic_notifier, 185 }; 186 187 static int __init heartbeat_trig_init(void) 188 { 189 int rc = led_trigger_register(&heartbeat_led_trigger); 190 191 if (!rc) { 192 atomic_notifier_chain_register(&panic_notifier_list, 193 &heartbeat_panic_nb); 194 register_reboot_notifier(&heartbeat_reboot_nb); 195 } 196 return rc; 197 } 198 199 static void __exit heartbeat_trig_exit(void) 200 { 201 unregister_reboot_notifier(&heartbeat_reboot_nb); 202 atomic_notifier_chain_unregister(&panic_notifier_list, 203 &heartbeat_panic_nb); 204 led_trigger_unregister(&heartbeat_led_trigger); 205 } 206 207 module_init(heartbeat_trig_init); 208 module_exit(heartbeat_trig_exit); 209 210 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 211 MODULE_DESCRIPTION("Heartbeat LED trigger"); 212 MODULE_LICENSE("GPL v2"); 213