1 /* 2 * LED Heartbeat Trigger 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * 6 * Based on Richard Purdie's ledtrig-timer.c and some arch's 7 * CONFIG_HEARTBEAT code. 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/slab.h> 18 #include <linux/timer.h> 19 #include <linux/sched.h> 20 #include <linux/sched/loadavg.h> 21 #include <linux/leds.h> 22 #include <linux/reboot.h> 23 #include "../leds.h" 24 25 static int panic_heartbeats; 26 27 struct heartbeat_trig_data { 28 struct led_classdev *led_cdev; 29 unsigned int phase; 30 unsigned int period; 31 struct timer_list timer; 32 unsigned int invert; 33 }; 34 35 static void led_heartbeat_function(struct timer_list *t) 36 { 37 struct heartbeat_trig_data *heartbeat_data = 38 from_timer(heartbeat_data, t, timer); 39 struct led_classdev *led_cdev; 40 unsigned long brightness = LED_OFF; 41 unsigned long delay = 0; 42 43 led_cdev = heartbeat_data->led_cdev; 44 45 if (unlikely(panic_heartbeats)) { 46 led_set_brightness_nosleep(led_cdev, LED_OFF); 47 return; 48 } 49 50 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags)) 51 led_cdev->blink_brightness = led_cdev->new_blink_brightness; 52 53 /* acts like an actual heart beat -- ie thump-thump-pause... */ 54 switch (heartbeat_data->phase) { 55 case 0: 56 /* 57 * The hyperbolic function below modifies the 58 * heartbeat period length in dependency of the 59 * current (1min) load. It goes through the points 60 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 61 */ 62 heartbeat_data->period = 300 + 63 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 64 heartbeat_data->period = 65 msecs_to_jiffies(heartbeat_data->period); 66 delay = msecs_to_jiffies(70); 67 heartbeat_data->phase++; 68 if (!heartbeat_data->invert) 69 brightness = led_cdev->blink_brightness; 70 break; 71 case 1: 72 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 73 heartbeat_data->phase++; 74 if (heartbeat_data->invert) 75 brightness = led_cdev->blink_brightness; 76 break; 77 case 2: 78 delay = msecs_to_jiffies(70); 79 heartbeat_data->phase++; 80 if (!heartbeat_data->invert) 81 brightness = led_cdev->blink_brightness; 82 break; 83 default: 84 delay = heartbeat_data->period - heartbeat_data->period / 4 - 85 msecs_to_jiffies(70); 86 heartbeat_data->phase = 0; 87 if (heartbeat_data->invert) 88 brightness = led_cdev->blink_brightness; 89 break; 90 } 91 92 led_set_brightness_nosleep(led_cdev, brightness); 93 mod_timer(&heartbeat_data->timer, jiffies + delay); 94 } 95 96 static ssize_t led_invert_show(struct device *dev, 97 struct device_attribute *attr, char *buf) 98 { 99 struct heartbeat_trig_data *heartbeat_data = 100 led_trigger_get_drvdata(dev); 101 102 return sprintf(buf, "%u\n", heartbeat_data->invert); 103 } 104 105 static ssize_t led_invert_store(struct device *dev, 106 struct device_attribute *attr, const char *buf, size_t size) 107 { 108 struct heartbeat_trig_data *heartbeat_data = 109 led_trigger_get_drvdata(dev); 110 unsigned long state; 111 int ret; 112 113 ret = kstrtoul(buf, 0, &state); 114 if (ret) 115 return ret; 116 117 heartbeat_data->invert = !!state; 118 119 return size; 120 } 121 122 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 123 124 static struct attribute *heartbeat_trig_attrs[] = { 125 &dev_attr_invert.attr, 126 NULL 127 }; 128 ATTRIBUTE_GROUPS(heartbeat_trig); 129 130 static int heartbeat_trig_activate(struct led_classdev *led_cdev) 131 { 132 struct heartbeat_trig_data *heartbeat_data; 133 134 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 135 if (!heartbeat_data) 136 return -ENOMEM; 137 138 led_set_trigger_data(led_cdev, heartbeat_data); 139 heartbeat_data->led_cdev = led_cdev; 140 141 timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0); 142 heartbeat_data->phase = 0; 143 if (!led_cdev->blink_brightness) 144 led_cdev->blink_brightness = led_cdev->max_brightness; 145 led_heartbeat_function(&heartbeat_data->timer); 146 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 147 148 return 0; 149 } 150 151 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 152 { 153 struct heartbeat_trig_data *heartbeat_data = 154 led_get_trigger_data(led_cdev); 155 156 del_timer_sync(&heartbeat_data->timer); 157 kfree(heartbeat_data); 158 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 159 } 160 161 static struct led_trigger heartbeat_led_trigger = { 162 .name = "heartbeat", 163 .activate = heartbeat_trig_activate, 164 .deactivate = heartbeat_trig_deactivate, 165 .groups = heartbeat_trig_groups, 166 }; 167 168 static int heartbeat_reboot_notifier(struct notifier_block *nb, 169 unsigned long code, void *unused) 170 { 171 led_trigger_unregister(&heartbeat_led_trigger); 172 return NOTIFY_DONE; 173 } 174 175 static int heartbeat_panic_notifier(struct notifier_block *nb, 176 unsigned long code, void *unused) 177 { 178 panic_heartbeats = 1; 179 return NOTIFY_DONE; 180 } 181 182 static struct notifier_block heartbeat_reboot_nb = { 183 .notifier_call = heartbeat_reboot_notifier, 184 }; 185 186 static struct notifier_block heartbeat_panic_nb = { 187 .notifier_call = heartbeat_panic_notifier, 188 }; 189 190 static int __init heartbeat_trig_init(void) 191 { 192 int rc = led_trigger_register(&heartbeat_led_trigger); 193 194 if (!rc) { 195 atomic_notifier_chain_register(&panic_notifier_list, 196 &heartbeat_panic_nb); 197 register_reboot_notifier(&heartbeat_reboot_nb); 198 } 199 return rc; 200 } 201 202 static void __exit heartbeat_trig_exit(void) 203 { 204 unregister_reboot_notifier(&heartbeat_reboot_nb); 205 atomic_notifier_chain_unregister(&panic_notifier_list, 206 &heartbeat_panic_nb); 207 led_trigger_unregister(&heartbeat_led_trigger); 208 } 209 210 module_init(heartbeat_trig_init); 211 module_exit(heartbeat_trig_exit); 212 213 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 214 MODULE_DESCRIPTION("Heartbeat LED trigger"); 215 MODULE_LICENSE("GPL v2"); 216