// SPDX-License-Identifier: GPL-2.0+
/* Xilinx GMII2RGMII Converter driver
 *
 * Copyright (C) 2016 Xilinx, Inc.
 * Copyright (C) 2016 Andrew Lunn <andrew@lunn.ch>
 *
 * Author: Andrew Lunn <andrew@lunn.ch>
 * Author: Kedareswara rao Appana <appanad@xilinx.com>
 *
 * Description:
 * This driver is developed for Xilinx GMII2RGMII Converter
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mii.h>
#include <linux/mdio.h>
#include <linux/phy.h>
#include <linux/clk.h>
#include <linux/of_mdio.h>

#define XILINX_GMII2RGMII_REG           0x10
#define XILINX_GMII2RGMII_SPEED_MASK    (BMCR_SPEED1000 | BMCR_SPEED100)

struct gmii2rgmii {
        struct phy_device *phy_dev;
        const struct phy_driver *phy_drv;
        struct phy_driver conv_phy_drv;
        struct mdio_device *mdio;
};

static void xgmiitorgmii_configure(struct gmii2rgmii *priv, int speed)
{
        struct mii_bus *bus = priv->mdio->bus;
        int addr = priv->mdio->addr;
        u16 val;

        val = mdiobus_read(bus, addr, XILINX_GMII2RGMII_REG);
        val &= ~XILINX_GMII2RGMII_SPEED_MASK;

        if (speed == SPEED_1000)
                val |= BMCR_SPEED1000;
        else if (speed == SPEED_100)
                val |= BMCR_SPEED100;
        else
                val |= BMCR_SPEED10;

        mdiobus_write(bus, addr, XILINX_GMII2RGMII_REG, val);
}

static int xgmiitorgmii_read_status(struct phy_device *phydev)
{
        struct gmii2rgmii *priv = mdiodev_get_drvdata(&phydev->mdio);
        int err;

        if (priv->phy_drv->read_status)
                err = priv->phy_drv->read_status(phydev);
        else
                err = genphy_read_status(phydev);
        if (err < 0)
                return err;

        xgmiitorgmii_configure(priv, phydev->speed);

        return 0;
}

static int xgmiitorgmii_set_loopback(struct phy_device *phydev, bool enable,
                                     int speed)
{
        struct gmii2rgmii *priv = mdiodev_get_drvdata(&phydev->mdio);
        int err;

        if (priv->phy_drv->set_loopback)
                err = priv->phy_drv->set_loopback(phydev, enable, speed);
        else
                err = genphy_loopback(phydev, enable, speed);
        if (err < 0)
                return err;

        xgmiitorgmii_configure(priv, phydev->speed);

        return 0;
}

static int xgmiitorgmii_probe(struct mdio_device *mdiodev)
{
        struct device *dev = &mdiodev->dev;
        struct device_node *np = dev->of_node, *phy_node;
        struct gmii2rgmii *priv;
        struct clk *clkin;

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

        clkin = devm_clk_get_optional_enabled(dev, NULL);
        if (IS_ERR(clkin))
                return dev_err_probe(dev, PTR_ERR(clkin),
                                        "Failed to get and enable clock from Device Tree\n");

        phy_node = of_parse_phandle(np, "phy-handle", 0);
        if (!phy_node) {
                dev_err(dev, "Couldn't parse phy-handle\n");
                return -ENODEV;
        }

        priv->phy_dev = of_phy_find_device(phy_node);
        of_node_put(phy_node);
        if (!priv->phy_dev) {
                dev_info(dev, "Couldn't find phydev\n");
                return -EPROBE_DEFER;
        }

        if (!priv->phy_dev->drv) {
                dev_info(dev, "Attached phy not ready\n");
                put_device(&priv->phy_dev->mdio.dev);
                return -EPROBE_DEFER;
        }

        priv->mdio = mdiodev;
        priv->phy_drv = priv->phy_dev->drv;
        memcpy(&priv->conv_phy_drv, priv->phy_dev->drv,
               sizeof(struct phy_driver));
        priv->conv_phy_drv.read_status = xgmiitorgmii_read_status;
        priv->conv_phy_drv.set_loopback = xgmiitorgmii_set_loopback;
        mdiodev_set_drvdata(&priv->phy_dev->mdio, priv);
        priv->phy_dev->drv = &priv->conv_phy_drv;

        return 0;
}

static const struct of_device_id xgmiitorgmii_of_match[] = {
        { .compatible = "xlnx,gmii-to-rgmii-1.0" },
        {},
};
MODULE_DEVICE_TABLE(of, xgmiitorgmii_of_match);

static struct mdio_driver xgmiitorgmii_driver = {
        .probe  = xgmiitorgmii_probe,
        .mdiodrv.driver = {
                .name = "xgmiitorgmii",
                .of_match_table = xgmiitorgmii_of_match,
        },
};

mdio_module_driver(xgmiitorgmii_driver);

MODULE_DESCRIPTION("Xilinx GMII2RGMII converter driver");
MODULE_LICENSE("GPL");