// SPDX-License-Identifier: GPL-2.0+
/*
 * A wrapper for multiple PHYs which passes all phy_* function calls to
 * multiple (actual) PHY devices. This is comes handy when initializing
 * all PHYs on a HCD and to keep them all in the same state.
 *
 * Copyright (C) 2018 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
 */

#include <linux/device.h>
#include <linux/list.h>
#include <linux/phy/phy.h>
#include <linux/of.h>

#include "phy.h"

struct usb_phy_roothub {
        struct phy              *phy;
        struct list_head        list;
};

static int usb_phy_roothub_add_phy(struct device *dev, int index,
                                   struct list_head *list)
{
        struct usb_phy_roothub *roothub_entry;
        struct phy *phy;

        phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
        if (IS_ERR(phy)) {
                if (PTR_ERR(phy) == -ENODEV)
                        return 0;
                else
                        return PTR_ERR(phy);
        }

        roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
        if (!roothub_entry)
                return -ENOMEM;

        INIT_LIST_HEAD(&roothub_entry->list);

        roothub_entry->phy = phy;

        list_add_tail(&roothub_entry->list, list);

        return 0;
}

struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
{
        struct usb_phy_roothub *phy_roothub;
        int i, num_phys, err;

        if (!IS_ENABLED(CONFIG_GENERIC_PHY))
                return NULL;

        num_phys = of_count_phandle_with_args(dev->of_node, "phys",
                                              "#phy-cells");
        if (num_phys <= 0)
                return NULL;

        phy_roothub = devm_kzalloc(dev, sizeof(*phy_roothub), GFP_KERNEL);
        if (!phy_roothub)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&phy_roothub->list);

        for (i = 0; i < num_phys; i++) {
                err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
                if (err)
                        return ERR_PTR(err);
        }

        return phy_roothub;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc);

int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub)
{
        struct usb_phy_roothub *roothub_entry;
        struct list_head *head;
        int err;

        if (!phy_roothub)
                return 0;

        head = &phy_roothub->list;

        list_for_each_entry(roothub_entry, head, list) {
                err = phy_init(roothub_entry->phy);
                if (err)
                        goto err_exit_phys;
        }

        return 0;

err_exit_phys:
        list_for_each_entry_continue_reverse(roothub_entry, head, list)
                phy_exit(roothub_entry->phy);

        return err;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_init);

int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub)
{
        struct usb_phy_roothub *roothub_entry;
        struct list_head *head;
        int err, ret = 0;

        if (!phy_roothub)
                return 0;

        head = &phy_roothub->list;

        list_for_each_entry(roothub_entry, head, list) {
                err = phy_exit(roothub_entry->phy);
                if (err)
                        ret = err;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_exit);

int usb_phy_roothub_set_mode(struct usb_phy_roothub *phy_roothub,
                             enum phy_mode mode)
{
        struct usb_phy_roothub *roothub_entry;
        struct list_head *head;
        int err;

        if (!phy_roothub)
                return 0;

        head = &phy_roothub->list;

        list_for_each_entry(roothub_entry, head, list) {
                err = phy_set_mode(roothub_entry->phy, mode);
                if (err)
                        goto err_out;
        }

        return 0;

err_out:
        list_for_each_entry_continue_reverse(roothub_entry, head, list)
                phy_power_off(roothub_entry->phy);

        return err;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_set_mode);

int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
{
        struct usb_phy_roothub *roothub_entry;
        struct list_head *head;
        int err;

        if (!phy_roothub)
                return 0;

        head = &phy_roothub->list;

        list_for_each_entry(roothub_entry, head, list) {
                err = phy_power_on(roothub_entry->phy);
                if (err)
                        goto err_out;
        }

        return 0;

err_out:
        list_for_each_entry_continue_reverse(roothub_entry, head, list)
                phy_power_off(roothub_entry->phy);

        return err;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_power_on);

void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub)
{
        struct usb_phy_roothub *roothub_entry;

        if (!phy_roothub)
                return;

        list_for_each_entry_reverse(roothub_entry, &phy_roothub->list, list)
                phy_power_off(roothub_entry->phy);
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_power_off);

int usb_phy_roothub_suspend(struct device *controller_dev,
                            struct usb_phy_roothub *phy_roothub)
{
        usb_phy_roothub_power_off(phy_roothub);

        /* keep the PHYs initialized so the device can wake up the system */
        if (device_may_wakeup(controller_dev))
                return 0;

        return usb_phy_roothub_exit(phy_roothub);
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_suspend);

int usb_phy_roothub_resume(struct device *controller_dev,
                           struct usb_phy_roothub *phy_roothub)
{
        int err;

        /* if the device can't wake up the system _exit was called */
        if (!device_may_wakeup(controller_dev)) {
                err = usb_phy_roothub_init(phy_roothub);
                if (err)
                        return err;
        }

        err = usb_phy_roothub_power_on(phy_roothub);

        /* undo _init if _power_on failed */
        if (err && !device_may_wakeup(controller_dev))
                usb_phy_roothub_exit(phy_roothub);

        return err;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_resume);