/*
   * 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/timer.h>
  #include <linux/err.h>

  #include <linux/ctype.h>

  #include <linux/leds.h>
  #include "leds.h"
  
  static struct class *leds_class;

  static void led_update_brightness(struct led_classdev *led_cdev)
  {
  	if (led_cdev->brightness_get)
  		led_cdev->brightness = led_cdev->brightness_get(led_cdev);
  }

  static ssize_t led_brightness_show(struct device *dev, 
  		struct device_attribute *attr, char *buf)

  {

  	struct led_classdev *led_cdev = dev_get_drvdata(dev);

  
  	/* no lock needed for this */

  	led_update_brightness(led_cdev);

  	return sprintf(buf, "%u
  ", led_cdev->brightness);

  }

  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 (isspace(*after))

  		count++;
  
  	if (count == size) {
  		ret = count;

  
  		if (state == LED_OFF)
  			led_trigger_remove(led_cdev);

  		led_set_brightness(led_cdev, state);
  	}
  
  	return ret;
  }

  static ssize_t led_max_brightness_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%u
  ", led_cdev->max_brightness);
  }

  static struct device_attribute led_class_attrs[] = {
  	__ATTR(brightness, 0644, led_brightness_show, led_brightness_store),

  	__ATTR(max_brightness, 0444, led_max_brightness_show, NULL),

  #ifdef CONFIG_LEDS_TRIGGERS

  	__ATTR(trigger, 0644, led_trigger_show, led_trigger_store),

  #endif

  	__ATTR_NULL,
  };

  static void led_timer_function(unsigned long data)
  {
  	struct led_classdev *led_cdev = (void *)data;
  	unsigned long brightness;
  	unsigned long delay;
  
  	if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  		led_set_brightness(led_cdev, LED_OFF);
  		return;
  	}
  
  	brightness = led_get_brightness(led_cdev);
  	if (!brightness) {
  		/* Time to switch the LED on. */
  		brightness = led_cdev->blink_brightness;
  		delay = led_cdev->blink_delay_on;
  	} else {
  		/* Store the current brightness value to be able
  		 * to restore it when the delay_off period is over.
  		 */
  		led_cdev->blink_brightness = brightness;
  		brightness = LED_OFF;
  		delay = led_cdev->blink_delay_off;
  	}
  
  	led_set_brightness(led_cdev, brightness);
  
  	mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
  }
  
  static void led_stop_software_blink(struct led_classdev *led_cdev)
  {
  	/* deactivate previous settings */
  	del_timer_sync(&led_cdev->blink_timer);
  	led_cdev->blink_delay_on = 0;
  	led_cdev->blink_delay_off = 0;
  }
  
  static void led_set_software_blink(struct led_classdev *led_cdev,
  				   unsigned long delay_on,
  				   unsigned long delay_off)
  {
  	int current_brightness;
  
  	current_brightness = led_get_brightness(led_cdev);
  	if (current_brightness)
  		led_cdev->blink_brightness = current_brightness;
  	if (!led_cdev->blink_brightness)
  		led_cdev->blink_brightness = led_cdev->max_brightness;

  	if (led_get_trigger_data(led_cdev) &&
  	    delay_on == led_cdev->blink_delay_on &&

  	    delay_off == led_cdev->blink_delay_off)
  		return;
  
  	led_stop_software_blink(led_cdev);
  
  	led_cdev->blink_delay_on = delay_on;
  	led_cdev->blink_delay_off = delay_off;
  
  	/* never on - don't blink */
  	if (!delay_on)
  		return;
  
  	/* never off - just set to brightness */
  	if (!delay_off) {
  		led_set_brightness(led_cdev, led_cdev->blink_brightness);
  		return;
  	}
  
  	mod_timer(&led_cdev->blink_timer, jiffies + 1);
  }

  /**
   * 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);

  static int led_suspend(struct device *dev, pm_message_t state)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  
  	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
  		led_classdev_suspend(led_cdev);
  
  	return 0;
  }
  
  static int led_resume(struct device *dev)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  
  	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
  		led_classdev_resume(led_cdev);
  
  	return 0;
  }

  /**
   * led_classdev_register - register a new object of led_classdev class.

   * @parent: 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)
  {

  	led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
  				      "%s", led_cdev->name);

  	if (IS_ERR(led_cdev->dev))

  		return PTR_ERR(led_cdev->dev);

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

  	/* add to the list of leds */

  	down_write(&leds_list_lock);

  	list_add_tail(&led_cdev->node, &leds_list);

  	up_write(&leds_list_lock);

  	if (!led_cdev->max_brightness)
  		led_cdev->max_brightness = LED_FULL;

  	led_update_brightness(led_cdev);

  	init_timer(&led_cdev->blink_timer);
  	led_cdev->blink_timer.function = led_timer_function;
  	led_cdev->blink_timer.data = (unsigned long)led_cdev;

  #ifdef CONFIG_LEDS_TRIGGERS

  	led_trigger_set_default(led_cdev);

  #endif

  	printk(KERN_DEBUG "Registered led device: %s
  ",

  			led_cdev->name);

  
  	return 0;
  }
  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)

  {

  #ifdef CONFIG_LEDS_TRIGGERS

  	down_write(&led_cdev->trigger_lock);

  	if (led_cdev->trigger)
  		led_trigger_set(led_cdev, NULL);

  	up_write(&led_cdev->trigger_lock);

  #endif

  	/* Stop blinking */
  	led_brightness_set(led_cdev, LED_OFF);

  	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);

  void led_blink_set(struct led_classdev *led_cdev,
  		   unsigned long *delay_on,
  		   unsigned long *delay_off)
  {

  	del_timer_sync(&led_cdev->blink_timer);

  	if (led_cdev->blink_set &&

  	    !led_cdev->blink_set(led_cdev, delay_on, delay_off))

  		return;
  
  	/* blink with 1 Hz as default if nothing specified */
  	if (!*delay_on && !*delay_off)
  		*delay_on = *delay_off = 500;
  
  	led_set_software_blink(led_cdev, *delay_on, *delay_off);
  }
  EXPORT_SYMBOL(led_blink_set);
  
  void led_brightness_set(struct led_classdev *led_cdev,
  			enum led_brightness brightness)
  {
  	led_stop_software_blink(led_cdev);
  	led_cdev->brightness_set(led_cdev, brightness);
  }
  EXPORT_SYMBOL(led_brightness_set);

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

  	leds_class->suspend = led_suspend;
  	leds_class->resume = led_resume;

  	leds_class->dev_attrs = led_class_attrs;

  	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");