/*
 * 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\n",
                        usb_phy_type_string(type));
                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);

/**
 * 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\n");
                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\n", 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\n");
                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)) {
                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\n");
                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\n");
}
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\n", 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\n",
                                                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\n");
                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);