// SPDX-License-Identifier: GPL-2.0+
/*
 * Hisilicon Fast Ethernet MDIO Bus Driver
 *
 * Copyright (c) 2016 HiSilicon Technologies Co., Ltd.
 */

#include <linux/clk.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_mdio.h>
#include <linux/platform_device.h>

#define MDIO_RWCTRL             0x00
#define MDIO_RO_DATA            0x04
#define MDIO_WRITE              BIT(13)
#define MDIO_RW_FINISH          BIT(15)
#define BIT_PHY_ADDR_OFFSET     8
#define BIT_WR_DATA_OFFSET      16

struct hisi_femac_mdio_data {
        struct clk *clk;
        void __iomem *membase;
};

static int hisi_femac_mdio_wait_ready(struct hisi_femac_mdio_data *data)
{
        u32 val;

        return readl_poll_timeout(data->membase + MDIO_RWCTRL,
                                  val, val & MDIO_RW_FINISH, 20, 10000);
}

static int hisi_femac_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
        struct hisi_femac_mdio_data *data = bus->priv;
        int ret;

        ret = hisi_femac_mdio_wait_ready(data);
        if (ret)
                return ret;

        writel((mii_id << BIT_PHY_ADDR_OFFSET) | regnum,
               data->membase + MDIO_RWCTRL);

        ret = hisi_femac_mdio_wait_ready(data);
        if (ret)
                return ret;

        return readl(data->membase + MDIO_RO_DATA) & 0xFFFF;
}

static int hisi_femac_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
                                 u16 value)
{
        struct hisi_femac_mdio_data *data = bus->priv;
        int ret;

        ret = hisi_femac_mdio_wait_ready(data);
        if (ret)
                return ret;

        writel(MDIO_WRITE | (value << BIT_WR_DATA_OFFSET) |
               (mii_id << BIT_PHY_ADDR_OFFSET) | regnum,
               data->membase + MDIO_RWCTRL);

        return hisi_femac_mdio_wait_ready(data);
}

static int hisi_femac_mdio_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct mii_bus *bus;
        struct hisi_femac_mdio_data *data;
        int ret;

        bus = mdiobus_alloc_size(sizeof(*data));
        if (!bus)
                return -ENOMEM;

        bus->name = "hisi_femac_mii_bus";
        bus->read = &hisi_femac_mdio_read;
        bus->write = &hisi_femac_mdio_write;
        snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
        bus->parent = &pdev->dev;

        data = bus->priv;
        data->membase = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->membase)) {
                ret = PTR_ERR(data->membase);
                goto err_out_free_mdiobus;
        }

        data->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(data->clk)) {
                ret = PTR_ERR(data->clk);
                goto err_out_free_mdiobus;
        }

        ret = clk_prepare_enable(data->clk);
        if (ret)
                goto err_out_free_mdiobus;

        ret = of_mdiobus_register(bus, np);
        if (ret)
                goto err_out_disable_clk;

        platform_set_drvdata(pdev, bus);

        return 0;

err_out_disable_clk:
        clk_disable_unprepare(data->clk);
err_out_free_mdiobus:
        mdiobus_free(bus);
        return ret;
}

static void hisi_femac_mdio_remove(struct platform_device *pdev)
{
        struct mii_bus *bus = platform_get_drvdata(pdev);
        struct hisi_femac_mdio_data *data = bus->priv;

        mdiobus_unregister(bus);
        clk_disable_unprepare(data->clk);
        mdiobus_free(bus);
}

static const struct of_device_id hisi_femac_mdio_dt_ids[] = {
        { .compatible = "hisilicon,hisi-femac-mdio" },
        { }
};
MODULE_DEVICE_TABLE(of, hisi_femac_mdio_dt_ids);

static struct platform_driver hisi_femac_mdio_driver = {
        .probe = hisi_femac_mdio_probe,
        .remove = hisi_femac_mdio_remove,
        .driver = {
                .name = "hisi-femac-mdio",
                .of_match_table = hisi_femac_mdio_dt_ids,
        },
};

module_platform_driver(hisi_femac_mdio_driver);

MODULE_DESCRIPTION("Hisilicon Fast Ethernet MAC MDIO interface driver");
MODULE_AUTHOR("Dongpo Li <lidongpo@hisilicon.com>");
MODULE_LICENSE("GPL");