/*
   * Generic implementation of a polled input device
  
   * Copyright (c) 2007 Dmitry Torokhov
   *
   * 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.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/jiffies.h>

  #include <linux/slab.h>

  #include <linux/mutex.h>

  #include <linux/workqueue.h>

  #include <linux/module.h>

  #include <linux/input-polldev.h>

  MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  MODULE_DESCRIPTION("Generic implementation of a polled input device");
  MODULE_LICENSE("GPL v2");
  MODULE_VERSION("0.1");

  static void input_polldev_queue_work(struct input_polled_dev *dev)

  {

  	unsigned long delay;

  	delay = msecs_to_jiffies(dev->poll_interval);
  	if (delay >= HZ)
  		delay = round_jiffies_relative(delay);

  	queue_delayed_work(system_freezable_wq, &dev->work, delay);

  }

  static void input_polled_device_work(struct work_struct *work)
  {
  	struct input_polled_dev *dev =
  		container_of(work, struct input_polled_dev, work.work);
  
  	dev->poll(dev);
  	input_polldev_queue_work(dev);
  }

  static int input_open_polled_device(struct input_dev *input)
  {

  	struct input_polled_dev *dev = input_get_drvdata(input);

  	if (dev->open)
  		dev->open(dev);

  	/* Only start polling if polling is enabled */

  	if (dev->poll_interval > 0) {
  		dev->poll(dev);
  		input_polldev_queue_work(dev);
  	}

  
  	return 0;
  }
  
  static void input_close_polled_device(struct input_dev *input)
  {

  	struct input_polled_dev *dev = input_get_drvdata(input);

  	cancel_delayed_work_sync(&dev->work);

  
  	if (dev->close)
  		dev->close(dev);

  }

  /* SYSFS interface */
  
  static ssize_t input_polldev_get_poll(struct device *dev,
  				      struct device_attribute *attr, char *buf)
  {
  	struct input_polled_dev *polldev = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%d
  ", polldev->poll_interval);
  }
  
  static ssize_t input_polldev_set_poll(struct device *dev,
  				struct device_attribute *attr, const char *buf,
  				size_t count)
  {
  	struct input_polled_dev *polldev = dev_get_drvdata(dev);
  	struct input_dev *input = polldev->input;

  	unsigned int interval;
  	int err;

  	err = kstrtouint(buf, 0, &interval);
  	if (err)
  		return err;

  
  	if (interval < polldev->poll_interval_min)
  		return -EINVAL;
  
  	if (interval > polldev->poll_interval_max)
  		return -EINVAL;
  
  	mutex_lock(&input->mutex);
  
  	polldev->poll_interval = interval;
  
  	if (input->users) {
  		cancel_delayed_work_sync(&polldev->work);
  		if (polldev->poll_interval > 0)
  			input_polldev_queue_work(polldev);
  	}
  
  	mutex_unlock(&input->mutex);
  
  	return count;
  }
  
  static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
  					    input_polldev_set_poll);
  
  
  static ssize_t input_polldev_get_max(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
  	struct input_polled_dev *polldev = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%d
  ", polldev->poll_interval_max);
  }
  
  static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
  
  static ssize_t input_polldev_get_min(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
  	struct input_polled_dev *polldev = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%d
  ", polldev->poll_interval_min);
  }
  
  static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
  
  static struct attribute *sysfs_attrs[] = {
  	&dev_attr_poll.attr,
  	&dev_attr_max.attr,
  	&dev_attr_min.attr,
  	NULL
  };
  
  static struct attribute_group input_polldev_attribute_group = {
  	.attrs = sysfs_attrs
  };

  static const struct attribute_group *input_polldev_attribute_groups[] = {
  	&input_polldev_attribute_group,
  	NULL
  };

  /**

   * input_allocate_polled_device - allocate memory for polled device

   *
   * The function allocates memory for a polled device and also
   * for an input device associated with this polled device.
   */
  struct input_polled_dev *input_allocate_polled_device(void)
  {
  	struct input_polled_dev *dev;
  
  	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
  	if (!dev)
  		return NULL;
  
  	dev->input = input_allocate_device();
  	if (!dev->input) {
  		kfree(dev);
  		return NULL;
  	}
  
  	return dev;
  }
  EXPORT_SYMBOL(input_allocate_polled_device);

  struct input_polled_devres {
  	struct input_polled_dev *polldev;
  };
  
  static int devm_input_polldev_match(struct device *dev, void *res, void *data)
  {
  	struct input_polled_devres *devres = res;
  
  	return devres->polldev == data;
  }
  
  static void devm_input_polldev_release(struct device *dev, void *res)
  {
  	struct input_polled_devres *devres = res;
  	struct input_polled_dev *polldev = devres->polldev;
  
  	dev_dbg(dev, "%s: dropping reference/freeing %s
  ",
  		__func__, dev_name(&polldev->input->dev));
  
  	input_put_device(polldev->input);
  	kfree(polldev);
  }
  
  static void devm_input_polldev_unregister(struct device *dev, void *res)
  {
  	struct input_polled_devres *devres = res;
  	struct input_polled_dev *polldev = devres->polldev;
  
  	dev_dbg(dev, "%s: unregistering device %s
  ",
  		__func__, dev_name(&polldev->input->dev));
  	input_unregister_device(polldev->input);
  
  	/*
  	 * Note that we are still holding extra reference to the input
  	 * device so it will stick around until devm_input_polldev_release()
  	 * is called.
  	 */
  }
  
  /**
   * devm_input_allocate_polled_device - allocate managed polled device
   * @dev: device owning the polled device being created
   *
   * Returns prepared &struct input_polled_dev or %NULL.
   *
   * Managed polled input devices do not need to be explicitly unregistered
   * or freed as it will be done automatically when owner device unbinds
   * from * its driver (or binding fails). Once such managed polled device
   * is allocated, it is ready to be set up and registered in the same
   * fashion as regular polled input devices (using
   * input_register_polled_device() function).
   *
   * If you want to manually unregister and free such managed polled devices,
   * it can be still done by calling input_unregister_polled_device() and
   * input_free_polled_device(), although it is rarely needed.
   *
   * NOTE: the owner device is set up as parent of input device and users
   * should not override it.
   */
  struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
  {
  	struct input_polled_dev *polldev;
  	struct input_polled_devres *devres;
  
  	devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
  			      GFP_KERNEL);
  	if (!devres)
  		return NULL;
  
  	polldev = input_allocate_polled_device();
  	if (!polldev) {
  		devres_free(devres);
  		return NULL;
  	}
  
  	polldev->input->dev.parent = dev;
  	polldev->devres_managed = true;
  
  	devres->polldev = polldev;
  	devres_add(dev, devres);
  
  	return polldev;
  }
  EXPORT_SYMBOL(devm_input_allocate_polled_device);

  /**
   * input_free_polled_device - free memory allocated for polled device
   * @dev: device to free
   *
   * The function frees memory allocated for polling device and drops

   * reference to the associated input device.

   */
  void input_free_polled_device(struct input_polled_dev *dev)
  {
  	if (dev) {

  		if (dev->devres_managed)
  			WARN_ON(devres_destroy(dev->input->dev.parent,
  						devm_input_polldev_release,
  						devm_input_polldev_match,
  						dev));
  		input_put_device(dev->input);

  		kfree(dev);
  	}
  }
  EXPORT_SYMBOL(input_free_polled_device);
  
  /**
   * input_register_polled_device - register polled device
   * @dev: device to register
   *
   * The function registers previously initialized polled input device
   * with input layer. The device should be allocated with call to
   * input_allocate_polled_device(). Callers should also set up poll()
   * method and set up capabilities (id, name, phys, bits) of the

   * corresponding input_dev structure.

   */
  int input_register_polled_device(struct input_polled_dev *dev)
  {

  	struct input_polled_devres *devres = NULL;

  	struct input_dev *input = dev->input;

  	int error;

  	if (dev->devres_managed) {
  		devres = devres_alloc(devm_input_polldev_unregister,
  				      sizeof(*devres), GFP_KERNEL);
  		if (!devres)
  			return -ENOMEM;
  
  		devres->polldev = dev;
  	}

  	input_set_drvdata(input, dev);

  	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);

  	if (!dev->poll_interval)
  		dev->poll_interval = 500;

  	if (!dev->poll_interval_max)
  		dev->poll_interval_max = dev->poll_interval;

  	input->open = input_open_polled_device;
  	input->close = input_close_polled_device;

  	input->dev.groups = input_polldev_attribute_groups;

  	error = input_register_device(input);

  	if (error) {
  		devres_free(devres);

  		return error;

  	}

  	/*
  	 * Take extra reference to the underlying input device so
  	 * that it survives call to input_unregister_polled_device()
  	 * and is deleted only after input_free_polled_device()
  	 * has been invoked. This is needed to ease task of freeing
  	 * sparse keymaps.
  	 */
  	input_get_device(input);

  	if (dev->devres_managed) {
  		dev_dbg(input->dev.parent, "%s: registering %s with devres.
  ",
  			__func__, dev_name(&input->dev));
  		devres_add(input->dev.parent, devres);
  	}

  	return 0;

  }
  EXPORT_SYMBOL(input_register_polled_device);
  
  /**
   * input_unregister_polled_device - unregister polled device
   * @dev: device to unregister
   *
   * The function unregisters previously registered polled input
   * device from input layer. Polling is stopped and device is
   * ready to be freed with call to input_free_polled_device().

   */
  void input_unregister_polled_device(struct input_polled_dev *dev)
  {

  	if (dev->devres_managed)
  		WARN_ON(devres_destroy(dev->input->dev.parent,
  					devm_input_polldev_unregister,
  					devm_input_polldev_match,
  					dev));

  	input_unregister_device(dev->input);

  }
  EXPORT_SYMBOL(input_unregister_polled_device);