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/leds.h>
  23 #include "leds.h"
  24
  25 static struct class *leds_class;
  26
  27 static ssize_t led_brightness_show(struct class_device *dev, char *buf)
  28 {
  29         struct led_classdev *led_cdev = class_get_devdata(dev);
  30         ssize_t ret = 0;
  31
  32         /* no lock needed for this */
  33         sprintf(buf, "%u\n", led_cdev->brightness);
  34         ret = strlen(buf) + 1;
  35
  36         return ret;
  37 }
  38
  39 static ssize_t led_brightness_store(struct class_device *dev,
  40                                 const char *buf, size_t size)
  41 {
  42         struct led_classdev *led_cdev = class_get_devdata(dev);
  43         ssize_t ret = -EINVAL;
  44         char *after;
  45         unsigned long state = simple_strtoul(buf, &after, 10);
  46
  47         if (after - buf > 0) {
  48                 ret = after - buf;
  49                 led_set_brightness(led_cdev, state);
  50         }
  51
  52         return ret;
  53 }
  54
  55 static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
  56                         led_brightness_store);
  57
  58 /**
  59  * led_classdev_suspend - suspend an led_classdev.
  60  * @led_cdev: the led_classdev to suspend.
  61  */
  62 void led_classdev_suspend(struct led_classdev *led_cdev)
  63 {
  64         led_cdev->flags |= LED_SUSPENDED;
  65         led_cdev->brightness_set(led_cdev, 0);
  66 }
  67 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  68
  69 /**
  70  * led_classdev_resume - resume an led_classdev.
  71  * @led_cdev: the led_classdev to resume.
  72  */
  73 void led_classdev_resume(struct led_classdev *led_cdev)
  74 {
  75         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  76         led_cdev->flags &= ~LED_SUSPENDED;
  77 }
  78 EXPORT_SYMBOL_GPL(led_classdev_resume);
  79
  80 /**
  81  * led_classdev_register - register a new object of led_classdev class.
  82  * @dev: The device to register.
  83  * @led_cdev: the led_classdev structure for this device.
  84  */
  85 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
  86 {
  87         led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
  88                                                 parent, "%s", led_cdev->name);
  89         if (unlikely(IS_ERR(led_cdev->class_dev)))
  90                 return PTR_ERR(led_cdev->class_dev);
  91
  92         class_set_devdata(led_cdev->class_dev, led_cdev);
  93
  94         /* register the attributes */
  95         class_device_create_file(led_cdev->class_dev,
  96                                 &class_device_attr_brightness);
  97
  98         /* add to the list of leds */
  99         write_lock(&leds_list_lock);
 100         list_add_tail(&led_cdev->node, &leds_list);
 101         write_unlock(&leds_list_lock);
 102
 103         printk(KERN_INFO "Registered led device: %s\n",
 104                         led_cdev->class_dev->class_id);
 105
 106         return 0;
 107 }
 108 EXPORT_SYMBOL_GPL(led_classdev_register);
 109
 110 /**
 111  * led_classdev_unregister - unregisters a object of led_properties class.
 112  * @led_cdev: the led device to unreigister
 113  *
 114  * Unregisters a previously registered via led_classdev_register object.
 115  */
 116 void led_classdev_unregister(struct led_classdev *led_cdev)
 117 {
 118         class_device_remove_file(led_cdev->class_dev,
 119                                 &class_device_attr_brightness);
 120
 121         class_device_unregister(led_cdev->class_dev);
 122
 123         write_lock(&leds_list_lock);
 124         list_del(&led_cdev->node);
 125         write_unlock(&leds_list_lock);
 126 }
 127 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 128
 129 static int __init leds_init(void)
 130 {
 131         leds_class = class_create(THIS_MODULE, "leds");
 132         if (IS_ERR(leds_class))
 133                 return PTR_ERR(leds_class);
 134         return 0;
 135 }
 136
 137 static void __exit leds_exit(void)
 138 {
 139         class_destroy(leds_class);
 140 }
 141
 142 subsys_initcall(leds_init);
 143 module_exit(leds_exit);
 144
 145 MODULE_AUTHOR("John Lenz, Richard Purdie");
 146 MODULE_LICENSE("GPL");
 147 MODULE_DESCRIPTION("LED Class Interface");