// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2025 Inochi Amaoto <inochiama@outlook.com>
 */

#include <linux/clk.h>
#include <linux/bitfield.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>

#define REG_USB_PHY_CTRL                0x048

#define PHY_VBUS_POWER_EN               BIT(0)
#define PHY_VBUS_POWER                  BIT(1)
#define PHY_ID_OVERWRITE_EN             BIT(6)
#define PHY_ID_OVERWRITE_MODE           BIT(7)
#define PHY_ID_OVERWRITE_MODE_HOST      FIELD_PREP(BIT(7), 0)
#define PHY_ID_OVERWRITE_MODE_DEVICE    FIELD_PREP(BIT(7), 1)

#define PHY_APP_CLK_RATE                125000000
#define PHY_LPM_CLK_RATE                12000000
#define PHY_STB_CLK_RATE                333334

struct cv1800_usb_phy {
        struct phy      *phy;
        struct regmap   *syscon;
        spinlock_t      lock;
        struct clk      *usb_app_clk;
        struct clk      *usb_lpm_clk;
        struct clk      *usb_stb_clk;
        bool            support_otg;
};

static int cv1800_usb_phy_set_mode(struct phy *_phy,
                                   enum phy_mode mode, int submode)
{
        struct cv1800_usb_phy *phy = phy_get_drvdata(_phy);
        unsigned int regval = 0;
        int ret;

        dev_info(&phy->phy->dev, "set mode %d", (int)mode);

        switch (mode) {
        case PHY_MODE_USB_DEVICE:
                regval = PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE_DEVICE;
                regmap_clear_bits(phy->syscon, REG_USB_PHY_CTRL, PHY_VBUS_POWER);
                break;
        case PHY_MODE_USB_HOST:
                regval = PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE_HOST;
                regmap_set_bits(phy->syscon, REG_USB_PHY_CTRL, PHY_VBUS_POWER);
                break;
        case PHY_MODE_USB_OTG:
                if (!phy->support_otg)
                        return 0;

                ret = regmap_read(phy->syscon, REG_USB_PHY_CTRL, &regval);
                if (ret)
                        return ret;

                regval = FIELD_GET(PHY_ID_OVERWRITE_MODE, regval);
                break;
        default:
                return -EINVAL;
        }

        return regmap_update_bits(phy->syscon, REG_USB_PHY_CTRL,
                                  PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE,
                                  regval);
}

static int cv1800_usb_phy_set_clock(struct cv1800_usb_phy *phy)
{
        int ret;

        ret = clk_set_rate(phy->usb_app_clk, PHY_APP_CLK_RATE);
        if (ret)
                return ret;

        ret = clk_set_rate(phy->usb_lpm_clk, PHY_LPM_CLK_RATE);
        if (ret)
                return ret;

        return clk_set_rate(phy->usb_stb_clk, PHY_STB_CLK_RATE);
}

static const struct phy_ops cv1800_usb_phy_ops = {
        .set_mode       = cv1800_usb_phy_set_mode,
        .owner          = THIS_MODULE,
};

static int cv1800_usb_phy_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device *parent = dev->parent;
        struct cv1800_usb_phy *phy;
        struct phy_provider *phy_provider;
        int ret;

        if (!parent)
                return -ENODEV;

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

        phy->syscon = syscon_node_to_regmap(parent->of_node);
        if (IS_ERR_OR_NULL(phy->syscon))
                return -ENODEV;

        phy->support_otg = false;

        spin_lock_init(&phy->lock);

        phy->usb_app_clk = devm_clk_get_enabled(dev, "app");
        if (IS_ERR(phy->usb_app_clk))
                return dev_err_probe(dev, PTR_ERR(phy->usb_app_clk),
                        "Failed to get app clock\n");

        phy->usb_lpm_clk = devm_clk_get_enabled(dev, "lpm");
        if (IS_ERR(phy->usb_lpm_clk))
                return dev_err_probe(dev, PTR_ERR(phy->usb_lpm_clk),
                        "Failed to get lpm clock\n");

        phy->usb_stb_clk = devm_clk_get_enabled(dev, "stb");
        if (IS_ERR(phy->usb_stb_clk))
                return dev_err_probe(dev, PTR_ERR(phy->usb_stb_clk),
                        "Failed to get stb clock\n");

        phy->phy = devm_phy_create(dev, NULL, &cv1800_usb_phy_ops);
        if (IS_ERR(phy->phy))
                return dev_err_probe(dev, PTR_ERR(phy->phy),
                        "Failed to create phy\n");

        ret = cv1800_usb_phy_set_clock(phy);
        if (ret)
                return ret;

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

        return PTR_ERR_OR_ZERO(phy_provider);
}

static const struct of_device_id cv1800_usb_phy_ids[] = {
        { .compatible = "sophgo,cv1800b-usb2-phy" },
        { },
};
MODULE_DEVICE_TABLE(of, cv1800_usb_phy_ids);

static struct platform_driver cv1800_usb_phy_driver = {
        .probe = cv1800_usb_phy_probe,
        .driver = {
                .name = "cv1800-usb2-phy",
                .of_match_table = cv1800_usb_phy_ids,
         },
};
module_platform_driver(cv1800_usb_phy_driver);

MODULE_AUTHOR("Inochi Amaoto <inochiama@outlook.com>");
MODULE_DESCRIPTION("CV1800/SG2000 SoC USB 2.0 PHY driver");
MODULE_LICENSE("GPL");