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 <linux/suspend.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 /* acts like an actual heart beat -- ie thump-thump-pause... */ 47 switch (heartbeat_data->phase) { 48 case 0: 49 /* 50 * The hyperbolic function below modifies the 51 * heartbeat period length in dependency of the 52 * current (1min) load. It goes through the points 53 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 54 */ 55 heartbeat_data->period = 300 + 56 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 57 heartbeat_data->period = 58 msecs_to_jiffies(heartbeat_data->period); 59 delay = msecs_to_jiffies(70); 60 heartbeat_data->phase++; 61 if (!heartbeat_data->invert) 62 brightness = led_cdev->max_brightness; 63 break; 64 case 1: 65 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 66 heartbeat_data->phase++; 67 if (heartbeat_data->invert) 68 brightness = led_cdev->max_brightness; 69 break; 70 case 2: 71 delay = msecs_to_jiffies(70); 72 heartbeat_data->phase++; 73 if (!heartbeat_data->invert) 74 brightness = led_cdev->max_brightness; 75 break; 76 default: 77 delay = heartbeat_data->period - heartbeat_data->period / 4 - 78 msecs_to_jiffies(70); 79 heartbeat_data->phase = 0; 80 if (heartbeat_data->invert) 81 brightness = led_cdev->max_brightness; 82 break; 83 } 84 85 led_set_brightness_nosleep(led_cdev, brightness); 86 mod_timer(&heartbeat_data->timer, jiffies + delay); 87 } 88 89 static ssize_t led_invert_show(struct device *dev, 90 struct device_attribute *attr, char *buf) 91 { 92 struct led_classdev *led_cdev = dev_get_drvdata(dev); 93 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 94 95 return sprintf(buf, "%u\n", heartbeat_data->invert); 96 } 97 98 static ssize_t led_invert_store(struct device *dev, 99 struct device_attribute *attr, const char *buf, size_t size) 100 { 101 struct led_classdev *led_cdev = dev_get_drvdata(dev); 102 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 103 unsigned long state; 104 int ret; 105 106 ret = kstrtoul(buf, 0, &state); 107 if (ret) 108 return ret; 109 110 heartbeat_data->invert = !!state; 111 112 return size; 113 } 114 115 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 116 117 static void heartbeat_trig_activate(struct led_classdev *led_cdev) 118 { 119 struct heartbeat_trig_data *heartbeat_data; 120 int rc; 121 122 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 123 if (!heartbeat_data) 124 return; 125 126 led_cdev->trigger_data = heartbeat_data; 127 rc = device_create_file(led_cdev->dev, &dev_attr_invert); 128 if (rc) { 129 kfree(led_cdev->trigger_data); 130 return; 131 } 132 133 setup_timer(&heartbeat_data->timer, 134 led_heartbeat_function, (unsigned long) led_cdev); 135 heartbeat_data->phase = 0; 136 led_heartbeat_function(heartbeat_data->timer.data); 137 led_cdev->activated = true; 138 } 139 140 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 141 { 142 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 143 144 if (led_cdev->activated) { 145 del_timer_sync(&heartbeat_data->timer); 146 device_remove_file(led_cdev->dev, &dev_attr_invert); 147 kfree(heartbeat_data); 148 led_cdev->activated = false; 149 } 150 } 151 152 static struct led_trigger heartbeat_led_trigger = { 153 .name = "heartbeat", 154 .activate = heartbeat_trig_activate, 155 .deactivate = heartbeat_trig_deactivate, 156 }; 157 158 static int heartbeat_pm_notifier(struct notifier_block *nb, 159 unsigned long pm_event, void *unused) 160 { 161 int rc; 162 163 switch (pm_event) { 164 case PM_SUSPEND_PREPARE: 165 case PM_HIBERNATION_PREPARE: 166 case PM_RESTORE_PREPARE: 167 led_trigger_unregister(&heartbeat_led_trigger); 168 break; 169 case PM_POST_SUSPEND: 170 case PM_POST_HIBERNATION: 171 case PM_POST_RESTORE: 172 rc = led_trigger_register(&heartbeat_led_trigger); 173 if (rc) 174 pr_err("could not re-register heartbeat trigger\n"); 175 break; 176 default: 177 break; 178 } 179 return NOTIFY_DONE; 180 } 181 182 static int heartbeat_reboot_notifier(struct notifier_block *nb, 183 unsigned long code, void *unused) 184 { 185 led_trigger_unregister(&heartbeat_led_trigger); 186 return NOTIFY_DONE; 187 } 188 189 static int heartbeat_panic_notifier(struct notifier_block *nb, 190 unsigned long code, void *unused) 191 { 192 panic_heartbeats = 1; 193 return NOTIFY_DONE; 194 } 195 196 static struct notifier_block heartbeat_pm_nb = { 197 .notifier_call = heartbeat_pm_notifier, 198 }; 199 200 static struct notifier_block heartbeat_reboot_nb = { 201 .notifier_call = heartbeat_reboot_notifier, 202 }; 203 204 static struct notifier_block heartbeat_panic_nb = { 205 .notifier_call = heartbeat_panic_notifier, 206 }; 207 208 static int __init heartbeat_trig_init(void) 209 { 210 int rc = led_trigger_register(&heartbeat_led_trigger); 211 212 if (!rc) { 213 atomic_notifier_chain_register(&panic_notifier_list, 214 &heartbeat_panic_nb); 215 register_reboot_notifier(&heartbeat_reboot_nb); 216 register_pm_notifier(&heartbeat_pm_nb); 217 } 218 return rc; 219 } 220 221 static void __exit heartbeat_trig_exit(void) 222 { 223 unregister_pm_notifier(&heartbeat_pm_nb); 224 unregister_reboot_notifier(&heartbeat_reboot_nb); 225 atomic_notifier_chain_unregister(&panic_notifier_list, 226 &heartbeat_panic_nb); 227 led_trigger_unregister(&heartbeat_led_trigger); 228 } 229 230 module_init(heartbeat_trig_init); 231 module_exit(heartbeat_trig_exit); 232 233 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 234 MODULE_DESCRIPTION("Heartbeat LED trigger"); 235 MODULE_LICENSE("GPL"); 236