// SPDX-License-Identifier: GPL-2.0+
/*
 * StarFive JH7110 USB 2.0 PHY driver
 *
 * Copyright (C) 2023 StarFive Technology Co., Ltd.
 * Author: Minda Chen <minda.chen@starfivetech.com>
 */

#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/usb/of.h>

#define USB_125M_CLK_RATE               125000000
#define USB_CLK_MODE_OFF                0x0
#define USB_CLK_MODE_RX_NORMAL_PWR      BIT(1)
#define USB_LS_KEEPALIVE_OFF            0x4
#define USB_LS_KEEPALIVE_ENABLE         BIT(4)

#define USB_PDRSTN_SPLIT                BIT(17)
#define SYSCON_USB_SPLIT_OFFSET         0x18

struct jh7110_usb2_phy {
        struct phy *phy;
        void __iomem *regs;
        struct regmap *sys_syscon;
        struct clk *usb_125m_clk;
        struct clk *app_125m;
        enum phy_mode mode;
};

static void usb2_set_ls_keepalive(struct jh7110_usb2_phy *phy, bool set)
{
        unsigned int val;

        /* Host mode enable the LS speed keep-alive signal */
        val = readl(phy->regs + USB_LS_KEEPALIVE_OFF);
        if (set)
                val |= USB_LS_KEEPALIVE_ENABLE;
        else
                val &= ~USB_LS_KEEPALIVE_ENABLE;

        writel(val, phy->regs + USB_LS_KEEPALIVE_OFF);
}

static int usb2_phy_set_mode(struct phy *_phy,
                             enum phy_mode mode, int submode)
{
        struct jh7110_usb2_phy *phy = phy_get_drvdata(_phy);

        switch (mode) {
        case PHY_MODE_USB_HOST:
        case PHY_MODE_USB_DEVICE:
        case PHY_MODE_USB_OTG:
                break;
        default:
                return -EINVAL;
        }

        if (mode != phy->mode) {
                dev_dbg(&_phy->dev, "Changing phy to %d\n", mode);
                phy->mode = mode;
                usb2_set_ls_keepalive(phy, (mode != PHY_MODE_USB_DEVICE));
        }

        /* Connect usb 2.0 phy mode */
        regmap_update_bits(phy->sys_syscon, SYSCON_USB_SPLIT_OFFSET,
                           USB_PDRSTN_SPLIT, USB_PDRSTN_SPLIT);

        return 0;
}

static int jh7110_usb2_phy_init(struct phy *_phy)
{
        struct jh7110_usb2_phy *phy = phy_get_drvdata(_phy);
        int ret;
        unsigned int val;

        ret = clk_set_rate(phy->usb_125m_clk, USB_125M_CLK_RATE);
        if (ret)
                return ret;

        ret = clk_prepare_enable(phy->app_125m);
        if (ret)
                return ret;

        val = readl(phy->regs + USB_CLK_MODE_OFF);
        val |= USB_CLK_MODE_RX_NORMAL_PWR;
        writel(val, phy->regs + USB_CLK_MODE_OFF);

        return 0;
}

static int jh7110_usb2_phy_exit(struct phy *_phy)
{
        struct jh7110_usb2_phy *phy = phy_get_drvdata(_phy);

        clk_disable_unprepare(phy->app_125m);

        return 0;
}

static const struct phy_ops jh7110_usb2_phy_ops = {
        .init           = jh7110_usb2_phy_init,
        .exit           = jh7110_usb2_phy_exit,
        .set_mode       = usb2_phy_set_mode,
        .owner          = THIS_MODULE,
};

static int jh7110_usb_phy_probe(struct platform_device *pdev)
{
        struct jh7110_usb2_phy *phy;
        struct device *dev = &pdev->dev;
        struct phy_provider *phy_provider;

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

        phy->usb_125m_clk = devm_clk_get(dev, "125m");
        if (IS_ERR(phy->usb_125m_clk))
                return dev_err_probe(dev, PTR_ERR(phy->usb_125m_clk),
                        "Failed to get 125m clock\n");

        phy->app_125m = devm_clk_get(dev, "app_125m");
        if (IS_ERR(phy->app_125m))
                return dev_err_probe(dev, PTR_ERR(phy->app_125m),
                        "Failed to get app 125m clock\n");

        phy->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(phy->regs))
                return dev_err_probe(dev, PTR_ERR(phy->regs),
                        "Failed to map phy base\n");

        phy->phy = devm_phy_create(dev, NULL, &jh7110_usb2_phy_ops);
        if (IS_ERR(phy->phy))
                return dev_err_probe(dev, PTR_ERR(phy->phy),
                        "Failed to create phy\n");

        phy_set_drvdata(phy->phy, phy);
        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

        phy->sys_syscon =
                syscon_regmap_lookup_by_compatible("starfive,jh7110-sys-syscon");
        if (IS_ERR(phy->sys_syscon))
                return dev_err_probe(dev, PTR_ERR(phy->sys_syscon),
                                     "Failed to get sys-syscon\n");

        return PTR_ERR_OR_ZERO(phy_provider);
}

static const struct of_device_id jh7110_usb_phy_of_match[] = {
        { .compatible = "starfive,jh7110-usb-phy" },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, jh7110_usb_phy_of_match);

static struct platform_driver jh7110_usb_phy_driver = {
        .probe  = jh7110_usb_phy_probe,
        .driver = {
                .of_match_table = jh7110_usb_phy_of_match,
                .name  = "jh7110-usb-phy",
        }
};
module_platform_driver(jh7110_usb_phy_driver);

MODULE_DESCRIPTION("StarFive JH7110 USB 2.0 PHY driver");
MODULE_AUTHOR("Minda Chen <minda.chen@starfivetech.com>");
MODULE_LICENSE("GPL");