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led-class.c

/*
 * LED Class Core
 *
 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/leds.h>
#include "leds.h"

static struct class *leds_class;

static ssize_t led_brightness_show(struct device *dev, 
            struct device_attribute *attr, char *buf)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      ssize_t ret = 0;

      /* no lock needed for this */
      sprintf(buf, "%u\n", led_cdev->brightness);
      ret = strlen(buf) + 1;

      return ret;
}

static ssize_t led_brightness_store(struct device *dev,
            struct device_attribute *attr, const char *buf, size_t size)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      ssize_t ret = -EINVAL;
      char *after;
      unsigned long state = simple_strtoul(buf, &after, 10);
      size_t count = after - buf;

      if (*after && isspace(*after))
            count++;

      if (count == size) {
            ret = count;
            led_set_brightness(led_cdev, state);
      }

      return ret;
}

static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
#ifdef CONFIG_LEDS_TRIGGERS
static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
#endif

/**
 * led_classdev_suspend - suspend an led_classdev.
 * @led_cdev: the led_classdev to suspend.
 */
void led_classdev_suspend(struct led_classdev *led_cdev)
{
      led_cdev->flags |= LED_SUSPENDED;
      led_cdev->brightness_set(led_cdev, 0);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

/**
 * led_classdev_resume - resume an led_classdev.
 * @led_cdev: the led_classdev to resume.
 */
void led_classdev_resume(struct led_classdev *led_cdev)
{
      led_cdev->brightness_set(led_cdev, led_cdev->brightness);
      led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);

/**
 * led_classdev_register - register a new object of led_classdev class.
 * @dev: The device to register.
 * @led_cdev: the led_classdev structure for this device.
 */
int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
{
      int rc;

      led_cdev->dev = device_create(leds_class, parent, 0, "%s",
                                  led_cdev->name);
      if (unlikely(IS_ERR(led_cdev->dev)))
            return PTR_ERR(led_cdev->dev);

      dev_set_drvdata(led_cdev->dev, led_cdev);

      /* register the attributes */
      rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
      if (rc)
            goto err_out;

      /* add to the list of leds */
      down_write(&leds_list_lock);
      list_add_tail(&led_cdev->node, &leds_list);
      up_write(&leds_list_lock);

#ifdef CONFIG_LEDS_TRIGGERS
      init_rwsem(&led_cdev->trigger_lock);

      rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
      if (rc)
            goto err_out_led_list;

      led_trigger_set_default(led_cdev);
#endif

      printk(KERN_INFO "Registered led device: %s\n",
                  led_cdev->name);

      return 0;

#ifdef CONFIG_LEDS_TRIGGERS
err_out_led_list:
      device_remove_file(led_cdev->dev, &dev_attr_brightness);
      list_del(&led_cdev->node);
#endif
err_out:
      device_unregister(led_cdev->dev);
      return rc;
}
EXPORT_SYMBOL_GPL(led_classdev_register);

/**
 * led_classdev_unregister - unregisters a object of led_properties class.
 * @led_cdev: the led device to unregister
 *
 * Unregisters a previously registered via led_classdev_register object.
 */
void led_classdev_unregister(struct led_classdev *led_cdev)
{
      device_remove_file(led_cdev->dev, &dev_attr_brightness);
#ifdef CONFIG_LEDS_TRIGGERS
      device_remove_file(led_cdev->dev, &dev_attr_trigger);
      down_write(&led_cdev->trigger_lock);
      if (led_cdev->trigger)
            led_trigger_set(led_cdev, NULL);
      up_write(&led_cdev->trigger_lock);
#endif

      device_unregister(led_cdev->dev);

      down_write(&leds_list_lock);
      list_del(&led_cdev->node);
      up_write(&leds_list_lock);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);

static int __init leds_init(void)
{
      leds_class = class_create(THIS_MODULE, "leds");
      if (IS_ERR(leds_class))
            return PTR_ERR(leds_class);
      return 0;
}

static void __exit leds_exit(void)
{
      class_destroy(leds_class);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");

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