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/sched/loadavg.h>
  21 #include <linux/leds.h>
  22 #include <linux/reboot.h>
  23 #include <linux/suspend.h>
  24 #include "../leds.h"
  25
  26 static int panic_heartbeats;
  27
  28 struct heartbeat_trig_data {
  29         unsigned int phase;
  30         unsigned int period;
  31         struct timer_list timer;
  32         unsigned int invert;
  33 };
  34
  35 static void led_heartbeat_function(unsigned long data)
  36 {
  37         struct led_classdev *led_cdev = (struct led_classdev *) data;
  38         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
  39         unsigned long brightness = LED_OFF;
  40         unsigned long delay = 0;
  41
  42         if (unlikely(panic_heartbeats)) {
  43                 led_set_brightness_nosleep(led_cdev, LED_OFF);
  44                 return;
  45         }
  46
  47         if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))
  48                 led_cdev->blink_brightness = led_cdev->new_blink_brightness;
  49
  50         /* acts like an actual heart beat -- ie thump-thump-pause... */
  51         switch (heartbeat_data->phase) {
  52         case 0:
  53                 /*
  54                  * The hyperbolic function below modifies the
  55                  * heartbeat period length in dependency of the
  56                  * current (1min) load. It goes through the points
  57                  * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
  58                  */
  59                 heartbeat_data->period = 300 +
  60                         (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
  61                 heartbeat_data->period =
  62                         msecs_to_jiffies(heartbeat_data->period);
  63                 delay = msecs_to_jiffies(70);
  64                 heartbeat_data->phase++;
  65                 if (!heartbeat_data->invert)
  66                         brightness = led_cdev->blink_brightness;
  67                 break;
  68         case 1:
  69                 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
  70                 heartbeat_data->phase++;
  71                 if (heartbeat_data->invert)
  72                         brightness = led_cdev->blink_brightness;
  73                 break;
  74         case 2:
  75                 delay = msecs_to_jiffies(70);
  76                 heartbeat_data->phase++;
  77                 if (!heartbeat_data->invert)
  78                         brightness = led_cdev->blink_brightness;
  79                 break;
  80         default:
  81                 delay = heartbeat_data->period - heartbeat_data->period / 4 -
  82                         msecs_to_jiffies(70);
  83                 heartbeat_data->phase = 0;
  84                 if (heartbeat_data->invert)
  85                         brightness = led_cdev->blink_brightness;
  86                 break;
  87         }
  88
  89         led_set_brightness_nosleep(led_cdev, brightness);
  90         mod_timer(&heartbeat_data->timer, jiffies + delay);
  91 }
  92
  93 static ssize_t led_invert_show(struct device *dev,
  94                 struct device_attribute *attr, char *buf)
  95 {
  96         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  97         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
  98
  99         return sprintf(buf, "%u\n", heartbeat_data->invert);
 100 }
 101
 102 static ssize_t led_invert_store(struct device *dev,
 103                 struct device_attribute *attr, const char *buf, size_t size)
 104 {
 105         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 106         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
 107         unsigned long state;
 108         int ret;
 109
 110         ret = kstrtoul(buf, 0, &state);
 111         if (ret)
 112                 return ret;
 113
 114         heartbeat_data->invert = !!state;
 115
 116         return size;
 117 }
 118
 119 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
 120
 121 static void heartbeat_trig_activate(struct led_classdev *led_cdev)
 122 {
 123         struct heartbeat_trig_data *heartbeat_data;
 124         int rc;
 125
 126         heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
 127         if (!heartbeat_data)
 128                 return;
 129
 130         led_cdev->trigger_data = heartbeat_data;
 131         rc = device_create_file(led_cdev->dev, &dev_attr_invert);
 132         if (rc) {
 133                 kfree(led_cdev->trigger_data);
 134                 return;
 135         }
 136
 137         setup_timer(&heartbeat_data->timer,
 138                     led_heartbeat_function, (unsigned long) led_cdev);
 139         heartbeat_data->phase = 0;
 140         if (!led_cdev->blink_brightness)
 141                 led_cdev->blink_brightness = led_cdev->max_brightness;
 142         led_heartbeat_function(heartbeat_data->timer.data);
 143         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 144         led_cdev->activated = true;
 145 }
 146
 147 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
 148 {
 149         struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
 150
 151         if (led_cdev->activated) {
 152                 del_timer_sync(&heartbeat_data->timer);
 153                 device_remove_file(led_cdev->dev, &dev_attr_invert);
 154                 kfree(heartbeat_data);
 155                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 156                 led_cdev->activated = false;
 157         }
 158 }
 159
 160 static struct led_trigger heartbeat_led_trigger = {
 161         .name     = "heartbeat",
 162         .activate = heartbeat_trig_activate,
 163         .deactivate = heartbeat_trig_deactivate,
 164 };
 165
 166 static int heartbeat_pm_notifier(struct notifier_block *nb,
 167                                  unsigned long pm_event, void *unused)
 168 {
 169         int rc;
 170
 171         switch (pm_event) {
 172         case PM_SUSPEND_PREPARE:
 173         case PM_HIBERNATION_PREPARE:
 174         case PM_RESTORE_PREPARE:
 175                 led_trigger_unregister(&heartbeat_led_trigger);
 176                 break;
 177         case PM_POST_SUSPEND:
 178         case PM_POST_HIBERNATION:
 179         case PM_POST_RESTORE:
 180                 rc = led_trigger_register(&heartbeat_led_trigger);
 181                 if (rc)
 182                         pr_err("could not re-register heartbeat trigger\n");
 183                 break;
 184         default:
 185                 break;
 186         }
 187         return NOTIFY_DONE;
 188 }
 189
 190 static int heartbeat_reboot_notifier(struct notifier_block *nb,
 191                                      unsigned long code, void *unused)
 192 {
 193         led_trigger_unregister(&heartbeat_led_trigger);
 194         return NOTIFY_DONE;
 195 }
 196
 197 static int heartbeat_panic_notifier(struct notifier_block *nb,
 198                                      unsigned long code, void *unused)
 199 {
 200         panic_heartbeats = 1;
 201         return NOTIFY_DONE;
 202 }
 203
 204 static struct notifier_block heartbeat_pm_nb = {
 205         .notifier_call = heartbeat_pm_notifier,
 206 };
 207
 208 static struct notifier_block heartbeat_reboot_nb = {
 209         .notifier_call = heartbeat_reboot_notifier,
 210 };
 211
 212 static struct notifier_block heartbeat_panic_nb = {
 213         .notifier_call = heartbeat_panic_notifier,
 214 };
 215
 216 static int __init heartbeat_trig_init(void)
 217 {
 218         int rc = led_trigger_register(&heartbeat_led_trigger);
 219
 220         if (!rc) {
 221                 atomic_notifier_chain_register(&panic_notifier_list,
 222                                                &heartbeat_panic_nb);
 223                 register_reboot_notifier(&heartbeat_reboot_nb);
 224                 register_pm_notifier(&heartbeat_pm_nb);
 225         }
 226         return rc;
 227 }
 228
 229 static void __exit heartbeat_trig_exit(void)
 230 {
 231         unregister_pm_notifier(&heartbeat_pm_nb);
 232         unregister_reboot_notifier(&heartbeat_reboot_nb);
 233         atomic_notifier_chain_unregister(&panic_notifier_list,
 234                                          &heartbeat_panic_nb);
 235         led_trigger_unregister(&heartbeat_led_trigger);
 236 }
 237
 238 module_init(heartbeat_trig_init);
 239 module_exit(heartbeat_trig_exit);
 240
 241 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 242 MODULE_DESCRIPTION("Heartbeat LED trigger");
 243 MODULE_LICENSE("GPL");