drivers/leds/trigger/ledtrig-heartbeat.c

   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");