drivers/leds/led-class.c

   1 /*
   2  * LED Class Core
   3  *
   4  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   5  * Copyright (C) 2005-2006 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/config.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/device.h>
  19 #include <linux/sysdev.h>
  20 #include <linux/timer.h>
  21 #include <linux/err.h>
  22 #include <linux/ctype.h>
  23 #include <linux/leds.h>
  24 #include "leds.h"
  25
  26 static struct class *leds_class;
  27
  28 static ssize_t led_brightness_show(struct class_device *dev, char *buf)
  29 {
  30         struct led_classdev *led_cdev = class_get_devdata(dev);
  31         ssize_t ret = 0;
  32
  33         /* no lock needed for this */
  34         sprintf(buf, "%u\n", led_cdev->brightness);
  35         ret = strlen(buf) + 1;
  36
  37         return ret;
  38 }
  39
  40 static ssize_t led_brightness_store(struct class_device *dev,
  41                                 const char *buf, size_t size)
  42 {
  43         struct led_classdev *led_cdev = class_get_devdata(dev);
  44         ssize_t ret = -EINVAL;
  45         char *after;
  46         unsigned long state = simple_strtoul(buf, &after, 10);
  47         size_t count = after - buf;
  48
  49         if (*after && isspace(*after))
  50                 count++;
  51
  52         if (count == size) {
  53                 ret = count;
  54                 led_set_brightness(led_cdev, state);
  55         }
  56
  57         return ret;
  58 }
  59
  60 static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
  61                         led_brightness_store);
  62 #ifdef CONFIG_LEDS_TRIGGERS
  63 static CLASS_DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  64 #endif
  65
  66 /**
  67  * led_classdev_suspend - suspend an led_classdev.
  68  * @led_cdev: the led_classdev to suspend.
  69  */
  70 void led_classdev_suspend(struct led_classdev *led_cdev)
  71 {
  72         led_cdev->flags |= LED_SUSPENDED;
  73         led_cdev->brightness_set(led_cdev, 0);
  74 }
  75 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  76
  77 /**
  78  * led_classdev_resume - resume an led_classdev.
  79  * @led_cdev: the led_classdev to resume.
  80  */
  81 void led_classdev_resume(struct led_classdev *led_cdev)
  82 {
  83         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  84         led_cdev->flags &= ~LED_SUSPENDED;
  85 }
  86 EXPORT_SYMBOL_GPL(led_classdev_resume);
  87
  88 /**
  89  * led_classdev_register - register a new object of led_classdev class.
  90  * @dev: The device to register.
  91  * @led_cdev: the led_classdev structure for this device.
  92  */
  93 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
  94 {
  95         led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
  96                                                 parent, "%s", led_cdev->name);
  97         if (unlikely(IS_ERR(led_cdev->class_dev)))
  98                 return PTR_ERR(led_cdev->class_dev);
  99
 100         class_set_devdata(led_cdev->class_dev, led_cdev);
 101
 102         /* register the attributes */
 103         class_device_create_file(led_cdev->class_dev,
 104                                 &class_device_attr_brightness);
 105
 106         /* add to the list of leds */
 107         write_lock(&leds_list_lock);
 108         list_add_tail(&led_cdev->node, &leds_list);
 109         write_unlock(&leds_list_lock);
 110
 111 #ifdef CONFIG_LEDS_TRIGGERS
 112         rwlock_init(&led_cdev->trigger_lock);
 113
 114         led_trigger_set_default(led_cdev);
 115
 116         class_device_create_file(led_cdev->class_dev,
 117                                 &class_device_attr_trigger);
 118 #endif
 119
 120         printk(KERN_INFO "Registered led device: %s\n",
 121                         led_cdev->class_dev->class_id);
 122
 123         return 0;
 124 }
 125 EXPORT_SYMBOL_GPL(led_classdev_register);
 126
 127 /**
 128  * led_classdev_unregister - unregisters a object of led_properties class.
 129  * @led_cdev: the led device to unreigister
 130  *
 131  * Unregisters a previously registered via led_classdev_register object.
 132  */
 133 void led_classdev_unregister(struct led_classdev *led_cdev)
 134 {
 135         class_device_remove_file(led_cdev->class_dev,
 136                                 &class_device_attr_brightness);
 137 #ifdef CONFIG_LEDS_TRIGGERS
 138         class_device_remove_file(led_cdev->class_dev,
 139                                 &class_device_attr_trigger);
 140         write_lock(&led_cdev->trigger_lock);
 141         if (led_cdev->trigger)
 142                 led_trigger_set(led_cdev, NULL);
 143         write_unlock(&led_cdev->trigger_lock);
 144 #endif
 145
 146         class_device_unregister(led_cdev->class_dev);
 147
 148         write_lock(&leds_list_lock);
 149         list_del(&led_cdev->node);
 150         write_unlock(&leds_list_lock);
 151 }
 152 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 153
 154 static int __init leds_init(void)
 155 {
 156         leds_class = class_create(THIS_MODULE, "leds");
 157         if (IS_ERR(leds_class))
 158                 return PTR_ERR(leds_class);
 159         return 0;
 160 }
 161
 162 static void __exit leds_exit(void)
 163 {
 164         class_destroy(leds_class);
 165 }
 166
 167 subsys_initcall(leds_init);
 168 module_exit(leds_exit);
 169
 170 MODULE_AUTHOR("John Lenz, Richard Purdie");
 171 MODULE_LICENSE("GPL");
 172 MODULE_DESCRIPTION("LED Class Interface");