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/leds.h> 21 #include <linux/reboot.h> 22 #include "../leds.h" 23 24 static int panic_heartbeats; 25 26 struct heartbeat_trig_data { 27 unsigned int phase; 28 unsigned int period; 29 struct timer_list timer; 30 unsigned int invert; 31 }; 32 33 static void led_heartbeat_function(unsigned long data) 34 { 35 struct led_classdev *led_cdev = (struct led_classdev *) data; 36 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 37 unsigned long brightness = LED_OFF; 38 unsigned long delay = 0; 39 40 if (unlikely(panic_heartbeats)) { 41 led_set_brightness(led_cdev, LED_OFF); 42 return; 43 } 44 45 /* acts like an actual heart beat -- ie thump-thump-pause... */ 46 switch (heartbeat_data->phase) { 47 case 0: 48 /* 49 * The hyperbolic function below modifies the 50 * heartbeat period length in dependency of the 51 * current (1min) load. It goes through the points 52 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 53 */ 54 heartbeat_data->period = 300 + 55 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 56 heartbeat_data->period = 57 msecs_to_jiffies(heartbeat_data->period); 58 delay = msecs_to_jiffies(70); 59 heartbeat_data->phase++; 60 if (!heartbeat_data->invert) 61 brightness = led_cdev->max_brightness; 62 break; 63 case 1: 64 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 65 heartbeat_data->phase++; 66 if (heartbeat_data->invert) 67 brightness = led_cdev->max_brightness; 68 break; 69 case 2: 70 delay = msecs_to_jiffies(70); 71 heartbeat_data->phase++; 72 if (!heartbeat_data->invert) 73 brightness = led_cdev->max_brightness; 74 break; 75 default: 76 delay = heartbeat_data->period - heartbeat_data->period / 4 - 77 msecs_to_jiffies(70); 78 heartbeat_data->phase = 0; 79 if (heartbeat_data->invert) 80 brightness = led_cdev->max_brightness; 81 break; 82 } 83 84 led_set_brightness_async(led_cdev, brightness); 85 mod_timer(&heartbeat_data->timer, jiffies + delay); 86 } 87 88 static ssize_t led_invert_show(struct device *dev, 89 struct device_attribute *attr, char *buf) 90 { 91 struct led_classdev *led_cdev = dev_get_drvdata(dev); 92 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 93 94 return sprintf(buf, "%u\n", heartbeat_data->invert); 95 } 96 97 static ssize_t led_invert_store(struct device *dev, 98 struct device_attribute *attr, const char *buf, size_t size) 99 { 100 struct led_classdev *led_cdev = dev_get_drvdata(dev); 101 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 102 unsigned long state; 103 int ret; 104 105 ret = kstrtoul(buf, 0, &state); 106 if (ret) 107 return ret; 108 109 heartbeat_data->invert = !!state; 110 111 return size; 112 } 113 114 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 115 116 static void heartbeat_trig_activate(struct led_classdev *led_cdev) 117 { 118 struct heartbeat_trig_data *heartbeat_data; 119 int rc; 120 121 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 122 if (!heartbeat_data) 123 return; 124 125 led_cdev->trigger_data = heartbeat_data; 126 rc = device_create_file(led_cdev->dev, &dev_attr_invert); 127 if (rc) { 128 kfree(led_cdev->trigger_data); 129 return; 130 } 131 132 setup_timer(&heartbeat_data->timer, 133 led_heartbeat_function, (unsigned long) led_cdev); 134 heartbeat_data->phase = 0; 135 led_heartbeat_function(heartbeat_data->timer.data); 136 led_cdev->activated = true; 137 } 138 139 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 140 { 141 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 142 143 if (led_cdev->activated) { 144 del_timer_sync(&heartbeat_data->timer); 145 device_remove_file(led_cdev->dev, &dev_attr_invert); 146 kfree(heartbeat_data); 147 led_cdev->activated = false; 148 } 149 } 150 151 static struct led_trigger heartbeat_led_trigger = { 152 .name = "heartbeat", 153 .activate = heartbeat_trig_activate, 154 .deactivate = heartbeat_trig_deactivate, 155 }; 156 157 static int heartbeat_reboot_notifier(struct notifier_block *nb, 158 unsigned long code, void *unused) 159 { 160 led_trigger_unregister(&heartbeat_led_trigger); 161 return NOTIFY_DONE; 162 } 163 164 static int heartbeat_panic_notifier(struct notifier_block *nb, 165 unsigned long code, void *unused) 166 { 167 panic_heartbeats = 1; 168 return NOTIFY_DONE; 169 } 170 171 static struct notifier_block heartbeat_reboot_nb = { 172 .notifier_call = heartbeat_reboot_notifier, 173 }; 174 175 static struct notifier_block heartbeat_panic_nb = { 176 .notifier_call = heartbeat_panic_notifier, 177 }; 178 179 static int __init heartbeat_trig_init(void) 180 { 181 int rc = led_trigger_register(&heartbeat_led_trigger); 182 183 if (!rc) { 184 atomic_notifier_chain_register(&panic_notifier_list, 185 &heartbeat_panic_nb); 186 register_reboot_notifier(&heartbeat_reboot_nb); 187 } 188 return rc; 189 } 190 191 static void __exit heartbeat_trig_exit(void) 192 { 193 unregister_reboot_notifier(&heartbeat_reboot_nb); 194 atomic_notifier_chain_unregister(&panic_notifier_list, 195 &heartbeat_panic_nb); 196 led_trigger_unregister(&heartbeat_led_trigger); 197 } 198 199 module_init(heartbeat_trig_init); 200 module_exit(heartbeat_trig_exit); 201 202 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 203 MODULE_DESCRIPTION("Heartbeat LED trigger"); 204 MODULE_LICENSE("GPL"); 205