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/sysdev.h>
  19 #include <linux/timer.h>
  20 #include <linux/err.h>
  21 #include <linux/ctype.h>
  22 #include <linux/leds.h>
  23 #include "leds.h"
  24
  25 static struct class *leds_class;
  26
  27 static void led_update_brightness(struct led_classdev *led_cdev)
  28 {
  29         if (led_cdev->brightness_get)
  30                 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
  31 }
  32
  33 static ssize_t led_brightness_show(struct device *dev,
  34                 struct device_attribute *attr, char *buf)
  35 {
  36         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  37
  38         /* no lock needed for this */
  39         led_update_brightness(led_cdev);
  40
  41         return sprintf(buf, "%u\n", led_cdev->brightness);
  42 }
  43
  44 static ssize_t led_brightness_store(struct device *dev,
  45                 struct device_attribute *attr, const char *buf, size_t size)
  46 {
  47         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  48         ssize_t ret = -EINVAL;
  49         char *after;
  50         unsigned long state = simple_strtoul(buf, &after, 10);
  51         size_t count = after - buf;
  52
  53         if (isspace(*after))
  54                 count++;
  55
  56         if (count == size) {
  57                 ret = count;
  58
  59                 if (state == LED_OFF)
  60                         led_trigger_remove(led_cdev);
  61                 led_set_brightness(led_cdev, state);
  62         }
  63
  64         return ret;
  65 }
  66
  67 static ssize_t led_max_brightness_show(struct device *dev,
  68                 struct device_attribute *attr, char *buf)
  69 {
  70         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  71
  72         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  73 }
  74
  75 static struct device_attribute led_class_attrs[] = {
  76         __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
  77         __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
  78 #ifdef CONFIG_LEDS_TRIGGERS
  79         __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
  80 #endif
  81         __ATTR_NULL,
  82 };
  83
  84 /**
  85  * led_classdev_suspend - suspend an led_classdev.
  86  * @led_cdev: the led_classdev to suspend.
  87  */
  88 void led_classdev_suspend(struct led_classdev *led_cdev)
  89 {
  90         led_cdev->flags |= LED_SUSPENDED;
  91         led_cdev->brightness_set(led_cdev, 0);
  92 }
  93 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  94
  95 /**
  96  * led_classdev_resume - resume an led_classdev.
  97  * @led_cdev: the led_classdev to resume.
  98  */
  99 void led_classdev_resume(struct led_classdev *led_cdev)
 100 {
 101         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
 102         led_cdev->flags &= ~LED_SUSPENDED;
 103 }
 104 EXPORT_SYMBOL_GPL(led_classdev_resume);
 105
 106 static int led_suspend(struct device *dev, pm_message_t state)
 107 {
 108         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 109
 110         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 111                 led_classdev_suspend(led_cdev);
 112
 113         return 0;
 114 }
 115
 116 static int led_resume(struct device *dev)
 117 {
 118         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 119
 120         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 121                 led_classdev_resume(led_cdev);
 122
 123         return 0;
 124 }
 125
 126 /**
 127  * led_classdev_register - register a new object of led_classdev class.
 128  * @parent: The device to register.
 129  * @led_cdev: the led_classdev structure for this device.
 130  */
 131 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 132 {
 133         led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
 134                                       "%s", led_cdev->name);
 135         if (IS_ERR(led_cdev->dev))
 136                 return PTR_ERR(led_cdev->dev);
 137
 138 #ifdef CONFIG_LEDS_TRIGGERS
 139         init_rwsem(&led_cdev->trigger_lock);
 140 #endif
 141         /* add to the list of leds */
 142         down_write(&leds_list_lock);
 143         list_add_tail(&led_cdev->node, &leds_list);
 144         up_write(&leds_list_lock);
 145
 146         if (!led_cdev->max_brightness)
 147                 led_cdev->max_brightness = LED_FULL;
 148
 149         led_update_brightness(led_cdev);
 150
 151 #ifdef CONFIG_LEDS_TRIGGERS
 152         led_trigger_set_default(led_cdev);
 153 #endif
 154
 155         printk(KERN_DEBUG "Registered led device: %s\n",
 156                         led_cdev->name);
 157
 158         return 0;
 159 }
 160
 161 EXPORT_SYMBOL_GPL(led_classdev_register);
 162
 163 /**
 164  * led_classdev_unregister - unregisters a object of led_properties class.
 165  * @led_cdev: the led device to unregister
 166  *
 167  * Unregisters a previously registered via led_classdev_register object.
 168  */
 169 void led_classdev_unregister(struct led_classdev *led_cdev)
 170 {
 171 #ifdef CONFIG_LEDS_TRIGGERS
 172         down_write(&led_cdev->trigger_lock);
 173         if (led_cdev->trigger)
 174                 led_trigger_set(led_cdev, NULL);
 175         up_write(&led_cdev->trigger_lock);
 176 #endif
 177
 178         device_unregister(led_cdev->dev);
 179
 180         down_write(&leds_list_lock);
 181         list_del(&led_cdev->node);
 182         up_write(&leds_list_lock);
 183 }
 184 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 185
 186 static int __init leds_init(void)
 187 {
 188         leds_class = class_create(THIS_MODULE, "leds");
 189         if (IS_ERR(leds_class))
 190                 return PTR_ERR(leds_class);
 191         leds_class->suspend = led_suspend;
 192         leds_class->resume = led_resume;
 193         leds_class->dev_attrs = led_class_attrs;
 194         return 0;
 195 }
 196
 197 static void __exit leds_exit(void)
 198 {
 199         class_destroy(leds_class);
 200 }
 201
 202 subsys_initcall(leds_init);
 203 module_exit(leds_exit);
 204
 205 MODULE_AUTHOR("John Lenz, Richard Purdie");
 206 MODULE_LICENSE("GPL");
 207 MODULE_DESCRIPTION("LED Class Interface");