/*
   * phy.c -- USB phy handling
   *
   * Copyright (C) 2004-2013 Texas Instruments
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  #include <linux/kernel.h>
  #include <linux/export.h>
  #include <linux/err.h>
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/of.h>
  
  #include <linux/usb/phy.h>
  
  static LIST_HEAD(phy_list);
  static LIST_HEAD(phy_bind_list);
  static DEFINE_SPINLOCK(phy_lock);
  
  static struct usb_phy *__usb_find_phy(struct list_head *list,
  	enum usb_phy_type type)
  {
  	struct usb_phy  *phy = NULL;
  
  	list_for_each_entry(phy, list, head) {
  		if (phy->type != type)
  			continue;
  
  		return phy;
  	}
  
  	return ERR_PTR(-ENODEV);
  }
  
  static struct usb_phy *__usb_find_phy_dev(struct device *dev,
  	struct list_head *list, u8 index)
  {
  	struct usb_phy_bind *phy_bind = NULL;
  
  	list_for_each_entry(phy_bind, list, list) {
  		if (!(strcmp(phy_bind->dev_name, dev_name(dev))) &&
  				phy_bind->index == index) {
  			if (phy_bind->phy)
  				return phy_bind->phy;
  			else
  				return ERR_PTR(-EPROBE_DEFER);
  		}
  	}
  
  	return ERR_PTR(-ENODEV);
  }
  
  static struct usb_phy *__of_usb_find_phy(struct device_node *node)
  {
  	struct usb_phy  *phy;
  
  	list_for_each_entry(phy, &phy_list, head) {
  		if (node != phy->dev->of_node)
  			continue;
  
  		return phy;
  	}
  
  	return ERR_PTR(-ENODEV);
  }
  
  static void devm_usb_phy_release(struct device *dev, void *res)
  {
  	struct usb_phy *phy = *(struct usb_phy **)res;
  
  	usb_put_phy(phy);
  }
  
  static int devm_usb_phy_match(struct device *dev, void *res, void *match_data)
  {
  	return res == match_data;
  }
  
  /**
   * devm_usb_get_phy - find the USB PHY
   * @dev - device that requests this phy
   * @type - the type of the phy the controller requires
   *
   * Gets the phy using usb_get_phy(), and associates a device with it using
   * devres. On driver detach, release function is invoked on the devres data,
   * then, devres data is freed.
   *
   * For use by USB host and peripheral drivers.
   */
  struct usb_phy *devm_usb_get_phy(struct device *dev, enum usb_phy_type type)
  {
  	struct usb_phy **ptr, *phy;
  
  	ptr = devres_alloc(devm_usb_phy_release, sizeof(*ptr), GFP_KERNEL);
  	if (!ptr)
  		return ERR_PTR(-ENOMEM);
  
  	phy = usb_get_phy(type);
  	if (!IS_ERR(phy)) {
  		*ptr = phy;
  		devres_add(dev, ptr);
  	} else
  		devres_free(ptr);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(devm_usb_get_phy);
  
  /**
   * usb_get_phy - find the USB PHY
   * @type - the type of the phy the controller requires
   *
   * Returns the phy driver, after getting a refcount to it; or
   * -ENODEV if there is no such phy.  The caller is responsible for
   * calling usb_put_phy() to release that count.
   *
   * For use by USB host and peripheral drivers.
   */
  struct usb_phy *usb_get_phy(enum usb_phy_type type)
  {
  	struct usb_phy	*phy = NULL;
  	unsigned long	flags;
  
  	spin_lock_irqsave(&phy_lock, flags);
  
  	phy = __usb_find_phy(&phy_list, type);
  	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
  		pr_debug("PHY: unable to find transceiver of type %s
  ",
  			usb_phy_type_string(type));
  		goto err0;
  	}
  
  	get_device(phy->dev);
  
  err0:
  	spin_unlock_irqrestore(&phy_lock, flags);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(usb_get_phy);
  
   /**
   * devm_usb_get_phy_by_phandle - find the USB PHY by phandle
   * @dev - device that requests this phy
   * @phandle - name of the property holding the phy phandle value
   * @index - the index of the phy
   *
   * Returns the phy driver associated with the given phandle value,
   * after getting a refcount to it, -ENODEV if there is no such phy or
   * -EPROBE_DEFER if there is a phandle to the phy, but the device is
   * not yet loaded. While at that, it also associates the device with
   * the phy using devres. On driver detach, release function is invoked
   * on the devres data, then, devres data is freed.
   *
   * For use by USB host and peripheral drivers.
   */
  struct usb_phy *devm_usb_get_phy_by_phandle(struct device *dev,
  	const char *phandle, u8 index)
  {
  	struct usb_phy	*phy = ERR_PTR(-ENOMEM), **ptr;
  	unsigned long	flags;
  	struct device_node *node;
  
  	if (!dev->of_node) {
  		dev_dbg(dev, "device does not have a device node entry
  ");
  		return ERR_PTR(-EINVAL);
  	}
  
  	node = of_parse_phandle(dev->of_node, phandle, index);
  	if (!node) {
  		dev_dbg(dev, "failed to get %s phandle in %s node
  ", phandle,
  			dev->of_node->full_name);
  		return ERR_PTR(-ENODEV);
  	}
  
  	ptr = devres_alloc(devm_usb_phy_release, sizeof(*ptr), GFP_KERNEL);
  	if (!ptr) {
  		dev_dbg(dev, "failed to allocate memory for devres
  ");
  		goto err0;
  	}
  
  	spin_lock_irqsave(&phy_lock, flags);
  
  	phy = __of_usb_find_phy(node);
  	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
  		if (!IS_ERR(phy))
  			phy = ERR_PTR(-EPROBE_DEFER);
  
  		devres_free(ptr);
  		goto err1;
  	}
  
  	*ptr = phy;
  	devres_add(dev, ptr);
  
  	get_device(phy->dev);
  
  err1:
  	spin_unlock_irqrestore(&phy_lock, flags);
  
  err0:
  	of_node_put(node);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(devm_usb_get_phy_by_phandle);
  
  /**
   * usb_get_phy_dev - find the USB PHY
   * @dev - device that requests this phy
   * @index - the index of the phy
   *
   * Returns the phy driver, after getting a refcount to it; or
   * -ENODEV if there is no such phy.  The caller is responsible for
   * calling usb_put_phy() to release that count.
   *
   * For use by USB host and peripheral drivers.
   */
  struct usb_phy *usb_get_phy_dev(struct device *dev, u8 index)
  {
  	struct usb_phy	*phy = NULL;
  	unsigned long	flags;
  
  	spin_lock_irqsave(&phy_lock, flags);
  
  	phy = __usb_find_phy_dev(dev, &phy_bind_list, index);
  	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
  		dev_dbg(dev, "unable to find transceiver
  ");
  		if (!IS_ERR(phy))
  			phy = ERR_PTR(-ENODEV);
  
  		goto err0;
  	}
  
  	get_device(phy->dev);
  
  err0:
  	spin_unlock_irqrestore(&phy_lock, flags);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(usb_get_phy_dev);
  
  /**
   * devm_usb_get_phy_dev - find the USB PHY using device ptr and index
   * @dev - device that requests this phy
   * @index - the index of the phy
   *
   * Gets the phy using usb_get_phy_dev(), and associates a device with it using
   * devres. On driver detach, release function is invoked on the devres data,
   * then, devres data is freed.
   *
   * For use by USB host and peripheral drivers.
   */
  struct usb_phy *devm_usb_get_phy_dev(struct device *dev, u8 index)
  {
  	struct usb_phy **ptr, *phy;
  
  	ptr = devres_alloc(devm_usb_phy_release, sizeof(*ptr), GFP_KERNEL);
  	if (!ptr)
  		return NULL;
  
  	phy = usb_get_phy_dev(dev, index);
  	if (!IS_ERR(phy)) {
  		*ptr = phy;
  		devres_add(dev, ptr);
  	} else
  		devres_free(ptr);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(devm_usb_get_phy_dev);
  
  /**
   * devm_usb_put_phy - release the USB PHY
   * @dev - device that wants to release this phy
   * @phy - the phy returned by devm_usb_get_phy()
   *
   * destroys the devres associated with this phy and invokes usb_put_phy
   * to release the phy.
   *
   * For use by USB host and peripheral drivers.
   */
  void devm_usb_put_phy(struct device *dev, struct usb_phy *phy)
  {
  	int r;
  
  	r = devres_destroy(dev, devm_usb_phy_release, devm_usb_phy_match, phy);
  	dev_WARN_ONCE(dev, r, "couldn't find PHY resource
  ");
  }
  EXPORT_SYMBOL_GPL(devm_usb_put_phy);
  
  /**
   * usb_put_phy - release the USB PHY
   * @x: the phy returned by usb_get_phy()
   *
   * Releases a refcount the caller received from usb_get_phy().
   *
   * For use by USB host and peripheral drivers.
   */
  void usb_put_phy(struct usb_phy *x)
  {
  	if (x) {
  		struct module *owner = x->dev->driver->owner;
  
  		put_device(x->dev);
  		module_put(owner);
  	}
  }
  EXPORT_SYMBOL_GPL(usb_put_phy);
  
  /**
   * usb_add_phy - declare the USB PHY
   * @x: the USB phy to be used; or NULL
   * @type - the type of this PHY
   *
   * This call is exclusively for use by phy drivers, which
   * coordinate the activities of drivers for host and peripheral
   * controllers, and in some cases for VBUS current regulation.
   */
  int usb_add_phy(struct usb_phy *x, enum usb_phy_type type)
  {
  	int		ret = 0;
  	unsigned long	flags;
  	struct usb_phy	*phy;
  
  	if (x->type != USB_PHY_TYPE_UNDEFINED) {
  		dev_err(x->dev, "not accepting initialized PHY %s
  ", x->label);
  		return -EINVAL;
  	}
  
  	ATOMIC_INIT_NOTIFIER_HEAD(&x->notifier);
  
  	spin_lock_irqsave(&phy_lock, flags);
  
  	list_for_each_entry(phy, &phy_list, head) {
  		if (phy->type == type) {
  			ret = -EBUSY;
  			dev_err(x->dev, "transceiver type %s already exists
  ",
  						usb_phy_type_string(type));
  			goto out;
  		}
  	}
  
  	x->type = type;
  	list_add_tail(&x->head, &phy_list);
  
  out:
  	spin_unlock_irqrestore(&phy_lock, flags);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(usb_add_phy);
  
  /**
   * usb_add_phy_dev - declare the USB PHY
   * @x: the USB phy to be used; or NULL
   *
   * This call is exclusively for use by phy drivers, which
   * coordinate the activities of drivers for host and peripheral
   * controllers, and in some cases for VBUS current regulation.
   */
  int usb_add_phy_dev(struct usb_phy *x)
  {
  	struct usb_phy_bind *phy_bind;
  	unsigned long flags;
  
  	if (!x->dev) {
  		dev_err(x->dev, "no device provided for PHY
  ");
  		return -EINVAL;
  	}
  
  	ATOMIC_INIT_NOTIFIER_HEAD(&x->notifier);
  
  	spin_lock_irqsave(&phy_lock, flags);
  	list_for_each_entry(phy_bind, &phy_bind_list, list)
  		if (!(strcmp(phy_bind->phy_dev_name, dev_name(x->dev))))
  			phy_bind->phy = x;
  
  	list_add_tail(&x->head, &phy_list);
  
  	spin_unlock_irqrestore(&phy_lock, flags);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usb_add_phy_dev);
  
  /**
   * usb_remove_phy - remove the OTG PHY
   * @x: the USB OTG PHY to be removed;
   *
   * This reverts the effects of usb_add_phy
   */
  void usb_remove_phy(struct usb_phy *x)
  {
  	unsigned long	flags;
  	struct usb_phy_bind *phy_bind;
  
  	spin_lock_irqsave(&phy_lock, flags);
  	if (x) {
  		list_for_each_entry(phy_bind, &phy_bind_list, list)
  			if (phy_bind->phy == x)
  				phy_bind->phy = NULL;
  		list_del(&x->head);
  	}
  	spin_unlock_irqrestore(&phy_lock, flags);
  }
  EXPORT_SYMBOL_GPL(usb_remove_phy);
  
  /**
   * usb_bind_phy - bind the phy and the controller that uses the phy
   * @dev_name: the device name of the device that will bind to the phy
   * @index: index to specify the port number
   * @phy_dev_name: the device name of the phy
   *
   * Fills the phy_bind structure with the dev_name and phy_dev_name. This will
   * be used when the phy driver registers the phy and when the controller
   * requests this phy.
   *
   * To be used by platform specific initialization code.
   */
  int usb_bind_phy(const char *dev_name, u8 index,
  				const char *phy_dev_name)
  {
  	struct usb_phy_bind *phy_bind;
  	unsigned long flags;
  
  	phy_bind = kzalloc(sizeof(*phy_bind), GFP_KERNEL);
  	if (!phy_bind)
  		return -ENOMEM;
  
  	phy_bind->dev_name = dev_name;
  	phy_bind->phy_dev_name = phy_dev_name;
  	phy_bind->index = index;
  
  	spin_lock_irqsave(&phy_lock, flags);
  	list_add_tail(&phy_bind->list, &phy_bind_list);
  	spin_unlock_irqrestore(&phy_lock, flags);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usb_bind_phy);