drivers/leds/led-class.c

   1 /*
   2  * LED Class Core
   3  *
   4  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   5  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/list.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/device.h>
  18 #include <linux/timer.h>
  19 #include <linux/err.h>
  20 #include <linux/ctype.h>
  21 #include <linux/leds.h>
  22 #include "leds.h"
  23
  24 static struct class *leds_class;
  25
  26 static void led_update_brightness(struct led_classdev *led_cdev)
  27 {
  28         if (led_cdev->brightness_get)
  29                 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
  30 }
  31
  32 static ssize_t led_brightness_show(struct device *dev,
  33                 struct device_attribute *attr, char *buf)
  34 {
  35         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  36
  37         /* no lock needed for this */
  38         led_update_brightness(led_cdev);
  39
  40         return sprintf(buf, "%u\n", led_cdev->brightness);
  41 }
  42
  43 static ssize_t led_brightness_store(struct device *dev,
  44                 struct device_attribute *attr, const char *buf, size_t size)
  45 {
  46         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  47         unsigned long state;
  48         ssize_t ret = -EINVAL;
  49
  50         ret = kstrtoul(buf, 10, &state);
  51         if (ret)
  52                 return ret;
  53
  54         if (state == LED_OFF)
  55                 led_trigger_remove(led_cdev);
  56         led_set_brightness(led_cdev, state);
  57
  58         return size;
  59 }
  60
  61 static ssize_t led_max_brightness_show(struct device *dev,
  62                 struct device_attribute *attr, char *buf)
  63 {
  64         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  65
  66         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  67 }
  68
  69 static struct device_attribute led_class_attrs[] = {
  70         __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
  71         __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
  72 #ifdef CONFIG_LEDS_TRIGGERS
  73         __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
  74 #endif
  75         __ATTR_NULL,
  76 };
  77
  78 static void led_timer_function(unsigned long data)
  79 {
  80         struct led_classdev *led_cdev = (void *)data;
  81         unsigned long brightness;
  82         unsigned long delay;
  83
  84         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  85                 led_set_brightness(led_cdev, LED_OFF);
  86                 return;
  87         }
  88
  89         brightness = led_get_brightness(led_cdev);
  90         if (!brightness) {
  91                 /* Time to switch the LED on. */
  92                 brightness = led_cdev->blink_brightness;
  93                 delay = led_cdev->blink_delay_on;
  94         } else {
  95                 /* Store the current brightness value to be able
  96                  * to restore it when the delay_off period is over.
  97                  */
  98                 led_cdev->blink_brightness = brightness;
  99                 brightness = LED_OFF;
 100                 delay = led_cdev->blink_delay_off;
 101         }
 102
 103         led_set_brightness(led_cdev, brightness);
 104
 105         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 106 }
 107
 108 /**
 109  * led_classdev_suspend - suspend an led_classdev.
 110  * @led_cdev: the led_classdev to suspend.
 111  */
 112 void led_classdev_suspend(struct led_classdev *led_cdev)
 113 {
 114         led_cdev->flags |= LED_SUSPENDED;
 115         led_cdev->brightness_set(led_cdev, 0);
 116 }
 117 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 118
 119 /**
 120  * led_classdev_resume - resume an led_classdev.
 121  * @led_cdev: the led_classdev to resume.
 122  */
 123 void led_classdev_resume(struct led_classdev *led_cdev)
 124 {
 125         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
 126         led_cdev->flags &= ~LED_SUSPENDED;
 127 }
 128 EXPORT_SYMBOL_GPL(led_classdev_resume);
 129
 130 static int led_suspend(struct device *dev, pm_message_t state)
 131 {
 132         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 133
 134         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 135                 led_classdev_suspend(led_cdev);
 136
 137         return 0;
 138 }
 139
 140 static int led_resume(struct device *dev)
 141 {
 142         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 143
 144         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 145                 led_classdev_resume(led_cdev);
 146
 147         return 0;
 148 }
 149
 150 /**
 151  * led_classdev_register - register a new object of led_classdev class.
 152  * @parent: The device to register.
 153  * @led_cdev: the led_classdev structure for this device.
 154  */
 155 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 156 {
 157         led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
 158                                       "%s", led_cdev->name);
 159         if (IS_ERR(led_cdev->dev))
 160                 return PTR_ERR(led_cdev->dev);
 161
 162 #ifdef CONFIG_LEDS_TRIGGERS
 163         init_rwsem(&led_cdev->trigger_lock);
 164 #endif
 165         /* add to the list of leds */
 166         down_write(&leds_list_lock);
 167         list_add_tail(&led_cdev->node, &leds_list);
 168         up_write(&leds_list_lock);
 169
 170         if (!led_cdev->max_brightness)
 171                 led_cdev->max_brightness = LED_FULL;
 172
 173         led_update_brightness(led_cdev);
 174
 175         init_timer(&led_cdev->blink_timer);
 176         led_cdev->blink_timer.function = led_timer_function;
 177         led_cdev->blink_timer.data = (unsigned long)led_cdev;
 178
 179 #ifdef CONFIG_LEDS_TRIGGERS
 180         led_trigger_set_default(led_cdev);
 181 #endif
 182
 183         printk(KERN_DEBUG "Registered led device: %s\n",
 184                         led_cdev->name);
 185
 186         return 0;
 187 }
 188 EXPORT_SYMBOL_GPL(led_classdev_register);
 189
 190 /**
 191  * led_classdev_unregister - unregisters a object of led_properties class.
 192  * @led_cdev: the led device to unregister
 193  *
 194  * Unregisters a previously registered via led_classdev_register object.
 195  */
 196 void led_classdev_unregister(struct led_classdev *led_cdev)
 197 {
 198 #ifdef CONFIG_LEDS_TRIGGERS
 199         down_write(&led_cdev->trigger_lock);
 200         if (led_cdev->trigger)
 201                 led_trigger_set(led_cdev, NULL);
 202         up_write(&led_cdev->trigger_lock);
 203 #endif
 204
 205         /* Stop blinking */
 206         led_brightness_set(led_cdev, LED_OFF);
 207
 208         device_unregister(led_cdev->dev);
 209
 210         down_write(&leds_list_lock);
 211         list_del(&led_cdev->node);
 212         up_write(&leds_list_lock);
 213 }
 214 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 215
 216 static int __init leds_init(void)
 217 {
 218         leds_class = class_create(THIS_MODULE, "leds");
 219         if (IS_ERR(leds_class))
 220                 return PTR_ERR(leds_class);
 221         leds_class->suspend = led_suspend;
 222         leds_class->resume = led_resume;
 223         leds_class->dev_attrs = led_class_attrs;
 224         return 0;
 225 }
 226
 227 static void __exit leds_exit(void)
 228 {
 229         class_destroy(leds_class);
 230 }
 231
 232 subsys_initcall(leds_init);
 233 module_exit(leds_exit);
 234
 235 MODULE_AUTHOR("John Lenz, Richard Purdie");
 236 MODULE_LICENSE("GPL");
 237 MODULE_DESCRIPTION("LED Class Interface");