// SPDX-License-Identifier: GPL-2.0+
/*
 * Atheros AR71XX/9XXX USB PHY driver
 *
 * Copyright (C) 2015-2018 Alban Bedel <albeu@free.fr>
 */

#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/reset.h>

struct ath79_usb_phy {
        struct reset_control *reset;
        /* The suspend override logic is inverted, hence the no prefix
         * to make the code a bit easier to understand.
         */
        struct reset_control *no_suspend_override;
};

static int ath79_usb_phy_power_on(struct phy *phy)
{
        struct ath79_usb_phy *priv = phy_get_drvdata(phy);
        int err = 0;

        if (priv->no_suspend_override) {
                err = reset_control_assert(priv->no_suspend_override);
                if (err)
                        return err;
        }

        err = reset_control_deassert(priv->reset);
        if (err && priv->no_suspend_override)
                reset_control_deassert(priv->no_suspend_override);

        return err;
}

static int ath79_usb_phy_power_off(struct phy *phy)
{
        struct ath79_usb_phy *priv = phy_get_drvdata(phy);
        int err = 0;

        err = reset_control_assert(priv->reset);
        if (err)
                return err;

        if (priv->no_suspend_override) {
                err = reset_control_deassert(priv->no_suspend_override);
                if (err)
                        reset_control_deassert(priv->reset);
        }

        return err;
}

static const struct phy_ops ath79_usb_phy_ops = {
        .power_on       = ath79_usb_phy_power_on,
        .power_off      = ath79_usb_phy_power_off,
        .owner          = THIS_MODULE,
};

static int ath79_usb_phy_probe(struct platform_device *pdev)
{
        struct ath79_usb_phy *priv;
        struct phy *phy;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->reset = devm_reset_control_get(&pdev->dev, "phy");
        if (IS_ERR(priv->reset))
                return PTR_ERR(priv->reset);

        priv->no_suspend_override = devm_reset_control_get_optional(
                &pdev->dev, "usb-suspend-override");
        if (IS_ERR(priv->no_suspend_override))
                return PTR_ERR(priv->no_suspend_override);

        phy = devm_phy_create(&pdev->dev, NULL, &ath79_usb_phy_ops);
        if (IS_ERR(phy))
                return PTR_ERR(phy);

        phy_set_drvdata(phy, priv);

        return PTR_ERR_OR_ZERO(devm_of_phy_provider_register(
                                &pdev->dev, of_phy_simple_xlate));
}

static const struct of_device_id ath79_usb_phy_of_match[] = {
        { .compatible = "qca,ar7100-usb-phy" },
        {}
};
MODULE_DEVICE_TABLE(of, ath79_usb_phy_of_match);

static struct platform_driver ath79_usb_phy_driver = {
        .probe  = ath79_usb_phy_probe,
        .driver = {
                .of_match_table = ath79_usb_phy_of_match,
                .name           = "ath79-usb-phy",
        }
};
module_platform_driver(ath79_usb_phy_driver);

MODULE_DESCRIPTION("ATH79 USB PHY driver");
MODULE_AUTHOR("Alban Bedel <albeu@free.fr>");
MODULE_LICENSE("GPL");