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 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_pm_notifier(struct notifier_block *nb, 166 unsigned long pm_event, void *unused) 167 { 168 int rc; 169 170 switch (pm_event) { 171 case PM_SUSPEND_PREPARE: 172 case PM_HIBERNATION_PREPARE: 173 case PM_RESTORE_PREPARE: 174 led_trigger_unregister(&heartbeat_led_trigger); 175 break; 176 case PM_POST_SUSPEND: 177 case PM_POST_HIBERNATION: 178 case PM_POST_RESTORE: 179 rc = led_trigger_register(&heartbeat_led_trigger); 180 if (rc) 181 pr_err("could not re-register heartbeat trigger\n"); 182 break; 183 default: 184 break; 185 } 186 return NOTIFY_DONE; 187 } 188 189 static int heartbeat_reboot_notifier(struct notifier_block *nb, 190 unsigned long code, void *unused) 191 { 192 led_trigger_unregister(&heartbeat_led_trigger); 193 return NOTIFY_DONE; 194 } 195 196 static int heartbeat_panic_notifier(struct notifier_block *nb, 197 unsigned long code, void *unused) 198 { 199 panic_heartbeats = 1; 200 return NOTIFY_DONE; 201 } 202 203 static struct notifier_block heartbeat_pm_nb = { 204 .notifier_call = heartbeat_pm_notifier, 205 }; 206 207 static struct notifier_block heartbeat_reboot_nb = { 208 .notifier_call = heartbeat_reboot_notifier, 209 }; 210 211 static struct notifier_block heartbeat_panic_nb = { 212 .notifier_call = heartbeat_panic_notifier, 213 }; 214 215 static int __init heartbeat_trig_init(void) 216 { 217 int rc = led_trigger_register(&heartbeat_led_trigger); 218 219 if (!rc) { 220 atomic_notifier_chain_register(&panic_notifier_list, 221 &heartbeat_panic_nb); 222 register_reboot_notifier(&heartbeat_reboot_nb); 223 register_pm_notifier(&heartbeat_pm_nb); 224 } 225 return rc; 226 } 227 228 static void __exit heartbeat_trig_exit(void) 229 { 230 unregister_pm_notifier(&heartbeat_pm_nb); 231 unregister_reboot_notifier(&heartbeat_reboot_nb); 232 atomic_notifier_chain_unregister(&panic_notifier_list, 233 &heartbeat_panic_nb); 234 led_trigger_unregister(&heartbeat_led_trigger); 235 } 236 237 module_init(heartbeat_trig_init); 238 module_exit(heartbeat_trig_exit); 239 240 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 241 MODULE_DESCRIPTION("Heartbeat LED trigger"); 242 MODULE_LICENSE("GPL"); 243