WSL2-Linux-Kernel/drivers/usb/core/phy.c

// 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_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);