git.oblomov.eu Git - linux-2.6/blob - 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 ssize_t led_brightness_show(struct device *dev,
  28                 struct device_attribute *attr, char *buf)
  29 {
  30         struct led_classdev *led_cdev = dev_get_drvdata(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 device *dev,
  41                 struct device_attribute *attr, const char *buf, size_t size)
  42 {
  43         struct led_classdev *led_cdev = dev_get_drvdata(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
  55                 if (state == LED_OFF)
  56                         led_trigger_remove(led_cdev);
  57                 led_set_brightness(led_cdev, state);
  58         }
  59
  60         return ret;
  61 }
  62
  63 static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
  64 #ifdef CONFIG_LEDS_TRIGGERS
  65 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  66 #endif
  67
  68 /**
  69  * led_classdev_suspend - suspend an led_classdev.
  70  * @led_cdev: the led_classdev to suspend.
  71  */
  72 void led_classdev_suspend(struct led_classdev *led_cdev)
  73 {
  74         led_cdev->flags |= LED_SUSPENDED;
  75         led_cdev->brightness_set(led_cdev, 0);
  76 }
  77 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  78
  79 /**
  80  * led_classdev_resume - resume an led_classdev.
  81  * @led_cdev: the led_classdev to resume.
  82  */
  83 void led_classdev_resume(struct led_classdev *led_cdev)
  84 {
  85         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  86         led_cdev->flags &= ~LED_SUSPENDED;
  87 }
  88 EXPORT_SYMBOL_GPL(led_classdev_resume);
  89
  90 /**
  91  * led_classdev_register - register a new object of led_classdev class.
  92  * @dev: The device to register.
  93  * @led_cdev: the led_classdev structure for this device.
  94  */
  95 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
  96 {
  97         int rc;
  98
  99         led_cdev->dev = device_create(leds_class, parent, 0, "%s",
 100                                             led_cdev->name);
 101         if (unlikely(IS_ERR(led_cdev->dev)))
 102                 return PTR_ERR(led_cdev->dev);
 103
 104         dev_set_drvdata(led_cdev->dev, led_cdev);
 105
 106         /* register the attributes */
 107         rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
 108         if (rc)
 109                 goto err_out;
 110
 111         /* add to the list of leds */
 112         down_write(&leds_list_lock);
 113         list_add_tail(&led_cdev->node, &leds_list);
 114         up_write(&leds_list_lock);
 115
 116 #ifdef CONFIG_LEDS_TRIGGERS
 117         init_rwsem(&led_cdev->trigger_lock);
 118
 119         rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
 120         if (rc)
 121                 goto err_out_led_list;
 122
 123         led_trigger_set_default(led_cdev);
 124 #endif
 125
 126         printk(KERN_INFO "Registered led device: %s\n",
 127                         led_cdev->name);
 128
 129         return 0;
 130
 131 #ifdef CONFIG_LEDS_TRIGGERS
 132 err_out_led_list:
 133         device_remove_file(led_cdev->dev, &dev_attr_brightness);
 134         list_del(&led_cdev->node);
 135 #endif
 136 err_out:
 137         device_unregister(led_cdev->dev);
 138         return rc;
 139 }
 140 EXPORT_SYMBOL_GPL(led_classdev_register);
 141
 142 /**
 143  * __led_classdev_unregister - unregisters a object of led_properties class.
 144  * @led_cdev: the led device to unregister
 145  *
 146  * Unregisters a previously registered via led_classdev_register object.
 147  */
 148 void led_classdev_unregister(struct led_classdev *led_cdev)
 149 {
 150         device_remove_file(led_cdev->dev, &dev_attr_brightness);
 151 #ifdef CONFIG_LEDS_TRIGGERS
 152         device_remove_file(led_cdev->dev, &dev_attr_trigger);
 153         down_write(&led_cdev->trigger_lock);
 154         if (led_cdev->trigger)
 155                 led_trigger_set(led_cdev, NULL);
 156         up_write(&led_cdev->trigger_lock);
 157 #endif
 158
 159         device_unregister(led_cdev->dev);
 160
 161         down_write(&leds_list_lock);
 162         list_del(&led_cdev->node);
 163         up_write(&leds_list_lock);
 164 }
 165 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 166
 167 static int __init leds_init(void)
 168 {
 169         leds_class = class_create(THIS_MODULE, "leds");
 170         if (IS_ERR(leds_class))
 171                 return PTR_ERR(leds_class);
 172         return 0;
 173 }
 174
 175 static void __exit leds_exit(void)
 176 {
 177         class_destroy(leds_class);
 178 }
 179
 180 subsys_initcall(leds_init);
 181 module_exit(leds_exit);
 182
 183 MODULE_AUTHOR("John Lenz, Richard Purdie");
 184 MODULE_LICENSE("GPL");
 185 MODULE_DESCRIPTION("LED Class Interface");