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 unsigned int phase; 29 unsigned int period; 30 struct timer_list timer; 31 unsigned int invert; 32 }; 33 34 static void led_heartbeat_function(unsigned long data) 35 { 36 struct led_classdev *led_cdev = (struct led_classdev *) data; 37 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 38 unsigned long brightness = LED_OFF; 39 unsigned long delay = 0; 40 41 if (unlikely(panic_heartbeats)) { 42 led_set_brightness_nosleep(led_cdev, LED_OFF); 43 return; 44 } 45 46 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags)) 47 led_cdev->blink_brightness = led_cdev->new_blink_brightness; 48 49 /* acts like an actual heart beat -- ie thump-thump-pause... */ 50 switch (heartbeat_data->phase) { 51 case 0: 52 /* 53 * The hyperbolic function below modifies the 54 * heartbeat period length in dependency of the 55 * current (1min) load. It goes through the points 56 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 57 */ 58 heartbeat_data->period = 300 + 59 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 60 heartbeat_data->period = 61 msecs_to_jiffies(heartbeat_data->period); 62 delay = msecs_to_jiffies(70); 63 heartbeat_data->phase++; 64 if (!heartbeat_data->invert) 65 brightness = led_cdev->blink_brightness; 66 break; 67 case 1: 68 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 69 heartbeat_data->phase++; 70 if (heartbeat_data->invert) 71 brightness = led_cdev->blink_brightness; 72 break; 73 case 2: 74 delay = msecs_to_jiffies(70); 75 heartbeat_data->phase++; 76 if (!heartbeat_data->invert) 77 brightness = led_cdev->blink_brightness; 78 break; 79 default: 80 delay = heartbeat_data->period - heartbeat_data->period / 4 - 81 msecs_to_jiffies(70); 82 heartbeat_data->phase = 0; 83 if (heartbeat_data->invert) 84 brightness = led_cdev->blink_brightness; 85 break; 86 } 87 88 led_set_brightness_nosleep(led_cdev, brightness); 89 mod_timer(&heartbeat_data->timer, jiffies + delay); 90 } 91 92 static ssize_t led_invert_show(struct device *dev, 93 struct device_attribute *attr, char *buf) 94 { 95 struct led_classdev *led_cdev = dev_get_drvdata(dev); 96 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 97 98 return sprintf(buf, "%u\n", heartbeat_data->invert); 99 } 100 101 static ssize_t led_invert_store(struct device *dev, 102 struct device_attribute *attr, const char *buf, size_t size) 103 { 104 struct led_classdev *led_cdev = dev_get_drvdata(dev); 105 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 106 unsigned long state; 107 int ret; 108 109 ret = kstrtoul(buf, 0, &state); 110 if (ret) 111 return ret; 112 113 heartbeat_data->invert = !!state; 114 115 return size; 116 } 117 118 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 119 120 static void heartbeat_trig_activate(struct led_classdev *led_cdev) 121 { 122 struct heartbeat_trig_data *heartbeat_data; 123 int rc; 124 125 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 126 if (!heartbeat_data) 127 return; 128 129 led_cdev->trigger_data = heartbeat_data; 130 rc = device_create_file(led_cdev->dev, &dev_attr_invert); 131 if (rc) { 132 kfree(led_cdev->trigger_data); 133 return; 134 } 135 136 setup_timer(&heartbeat_data->timer, 137 led_heartbeat_function, (unsigned long) led_cdev); 138 heartbeat_data->phase = 0; 139 if (!led_cdev->blink_brightness) 140 led_cdev->blink_brightness = led_cdev->max_brightness; 141 led_heartbeat_function(heartbeat_data->timer.data); 142 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 143 led_cdev->activated = true; 144 } 145 146 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 147 { 148 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 149 150 if (led_cdev->activated) { 151 del_timer_sync(&heartbeat_data->timer); 152 device_remove_file(led_cdev->dev, &dev_attr_invert); 153 kfree(heartbeat_data); 154 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 155 led_cdev->activated = false; 156 } 157 } 158 159 static struct led_trigger heartbeat_led_trigger = { 160 .name = "heartbeat", 161 .activate = heartbeat_trig_activate, 162 .deactivate = heartbeat_trig_deactivate, 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"); 213