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/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 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         size_t count = after - buf;
  47
  48         if (*after && isspace(*after))
  49                 count++;
  50
  51         if (count == size) {
  52                 ret = count;
  53                 led_set_brightness(led_cdev, state);
  54         }
  55
  56         return ret;
  57 }
  58
  59 static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
  60                         led_brightness_store);
  61 #ifdef CONFIG_LEDS_TRIGGERS
  62 static CLASS_DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  63 #endif
  64
  65 /**
  66  * led_classdev_suspend - suspend an led_classdev.
  67  * @led_cdev: the led_classdev to suspend.
  68  */
  69 void led_classdev_suspend(struct led_classdev *led_cdev)
  70 {
  71         led_cdev->flags |= LED_SUSPENDED;
  72         led_cdev->brightness_set(led_cdev, 0);
  73 }
  74 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  75
  76 /**
  77  * led_classdev_resume - resume an led_classdev.
  78  * @led_cdev: the led_classdev to resume.
  79  */
  80 void led_classdev_resume(struct led_classdev *led_cdev)
  81 {
  82         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  83         led_cdev->flags &= ~LED_SUSPENDED;
  84 }
  85 EXPORT_SYMBOL_GPL(led_classdev_resume);
  86
  87 /**
  88  * led_classdev_register - register a new object of led_classdev class.
  89  * @dev: The device to register.
  90  * @led_cdev: the led_classdev structure for this device.
  91  */
  92 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
  93 {
  94         led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
  95                                                 parent, "%s", led_cdev->name);
  96         if (unlikely(IS_ERR(led_cdev->class_dev)))
  97                 return PTR_ERR(led_cdev->class_dev);
  98
  99         class_set_devdata(led_cdev->class_dev, led_cdev);
 100
 101         /* register the attributes */
 102         class_device_create_file(led_cdev->class_dev,
 103                                 &class_device_attr_brightness);
 104
 105         /* add to the list of leds */
 106         write_lock(&leds_list_lock);
 107         list_add_tail(&led_cdev->node, &leds_list);
 108         write_unlock(&leds_list_lock);
 109
 110 #ifdef CONFIG_LEDS_TRIGGERS
 111         rwlock_init(&led_cdev->trigger_lock);
 112
 113         led_trigger_set_default(led_cdev);
 114
 115         class_device_create_file(led_cdev->class_dev,
 116                                 &class_device_attr_trigger);
 117 #endif
 118
 119         printk(KERN_INFO "Registered led device: %s\n",
 120                         led_cdev->class_dev->class_id);
 121
 122         return 0;
 123 }
 124 EXPORT_SYMBOL_GPL(led_classdev_register);
 125
 126 /**
 127  * led_classdev_unregister - unregisters a object of led_properties class.
 128  * @led_cdev: the led device to unregister
 129  *
 130  * Unregisters a previously registered via led_classdev_register object.
 131  */
 132 void led_classdev_unregister(struct led_classdev *led_cdev)
 133 {
 134         class_device_remove_file(led_cdev->class_dev,
 135                                 &class_device_attr_brightness);
 136 #ifdef CONFIG_LEDS_TRIGGERS
 137         class_device_remove_file(led_cdev->class_dev,
 138                                 &class_device_attr_trigger);
 139         write_lock(&led_cdev->trigger_lock);
 140         if (led_cdev->trigger)
 141                 led_trigger_set(led_cdev, NULL);
 142         write_unlock(&led_cdev->trigger_lock);
 143 #endif
 144
 145         class_device_unregister(led_cdev->class_dev);
 146
 147         write_lock(&leds_list_lock);
 148         list_del(&led_cdev->node);
 149         write_unlock(&leds_list_lock);
 150 }
 151 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 152
 153 static int __init leds_init(void)
 154 {
 155         leds_class = class_create(THIS_MODULE, "leds");
 156         if (IS_ERR(leds_class))
 157                 return PTR_ERR(leds_class);
 158         return 0;
 159 }
 160
 161 static void __exit leds_exit(void)
 162 {
 163         class_destroy(leds_class);
 164 }
 165
 166 subsys_initcall(leds_init);
 167 module_exit(leds_exit);
 168
 169 MODULE_AUTHOR("John Lenz, Richard Purdie");
 170 MODULE_LICENSE("GPL");
 171 MODULE_DESCRIPTION("LED Class Interface");