// SPDX-License-Identifier: GPL-2.0+
/*
 * Allwinner sun50i(H6) USB 3.0 phy driver
 *
 * Copyright (C) 2017 Icenowy Zheng <icenowy@aosc.io>
 *
 * Based on phy-sun9i-usb.c, which is:
 *
 * Copyright (C) 2014-2015 Chen-Yu Tsai <wens@csie.org>
 *
 * Based on code from Allwinner BSP, which is:
 *
 * Copyright (c) 2010-2015 Allwinner Technology Co., Ltd.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/reset.h>

/* Interface Status and Control Registers */
#define SUNXI_ISCR                      0x00
#define SUNXI_PIPE_CLOCK_CONTROL        0x14
#define SUNXI_PHY_TUNE_LOW              0x18
#define SUNXI_PHY_TUNE_HIGH             0x1c
#define SUNXI_PHY_EXTERNAL_CONTROL      0x20

/* USB2.0 Interface Status and Control Register */
#define SUNXI_ISCR_FORCE_VBUS           (3 << 12)

/* PIPE Clock Control Register */
#define SUNXI_PCC_PIPE_CLK_OPEN         (1 << 6)

/* PHY External Control Register */
#define SUNXI_PEC_EXTERN_VBUS           (3 << 1)
#define SUNXI_PEC_SSC_EN                (1 << 24)
#define SUNXI_PEC_REF_SSP_EN            (1 << 26)

/* PHY Tune High Register */
#define SUNXI_TX_DEEMPH_3P5DB(n)        ((n) << 19)
#define SUNXI_TX_DEEMPH_3P5DB_MASK      GENMASK(24, 19)
#define SUNXI_TX_DEEMPH_6DB(n)          ((n) << 13)
#define SUNXI_TX_DEEMPH_6GB_MASK        GENMASK(18, 13)
#define SUNXI_TX_SWING_FULL(n)          ((n) << 6)
#define SUNXI_TX_SWING_FULL_MASK        GENMASK(12, 6)
#define SUNXI_LOS_BIAS(n)               ((n) << 3)
#define SUNXI_LOS_BIAS_MASK             GENMASK(5, 3)
#define SUNXI_TXVBOOSTLVL(n)            ((n) << 0)
#define SUNXI_TXVBOOSTLVL_MASK          GENMASK(2, 0)

struct sun50i_usb3_phy {
        struct phy *phy;
        void __iomem *regs;
        struct reset_control *reset;
        struct clk *clk;
};

static void sun50i_usb3_phy_open(struct sun50i_usb3_phy *phy)
{
        u32 val;

        val = readl(phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);
        val |= SUNXI_PEC_EXTERN_VBUS;
        val |= SUNXI_PEC_SSC_EN | SUNXI_PEC_REF_SSP_EN;
        writel(val, phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);

        val = readl(phy->regs + SUNXI_PIPE_CLOCK_CONTROL);
        val |= SUNXI_PCC_PIPE_CLK_OPEN;
        writel(val, phy->regs + SUNXI_PIPE_CLOCK_CONTROL);

        val = readl(phy->regs + SUNXI_ISCR);
        val |= SUNXI_ISCR_FORCE_VBUS;
        writel(val, phy->regs + SUNXI_ISCR);

        /*
         * All the magic numbers written to the PHY_TUNE_{LOW_HIGH}
         * registers are directly taken from the BSP USB3 driver from
         * Allwiner.
         */
        writel(0x0047fc87, phy->regs + SUNXI_PHY_TUNE_LOW);

        val = readl(phy->regs + SUNXI_PHY_TUNE_HIGH);
        val &= ~(SUNXI_TXVBOOSTLVL_MASK | SUNXI_LOS_BIAS_MASK |
                 SUNXI_TX_SWING_FULL_MASK | SUNXI_TX_DEEMPH_6GB_MASK |
                 SUNXI_TX_DEEMPH_3P5DB_MASK);
        val |= SUNXI_TXVBOOSTLVL(0x7);
        val |= SUNXI_LOS_BIAS(0x7);
        val |= SUNXI_TX_SWING_FULL(0x55);
        val |= SUNXI_TX_DEEMPH_6DB(0x20);
        val |= SUNXI_TX_DEEMPH_3P5DB(0x15);
        writel(val, phy->regs + SUNXI_PHY_TUNE_HIGH);
}

static int sun50i_usb3_phy_init(struct phy *_phy)
{
        struct sun50i_usb3_phy *phy = phy_get_drvdata(_phy);
        int ret;

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

        ret = reset_control_deassert(phy->reset);
        if (ret) {
                clk_disable_unprepare(phy->clk);
                return ret;
        }

        sun50i_usb3_phy_open(phy);
        return 0;
}

static int sun50i_usb3_phy_exit(struct phy *_phy)
{
        struct sun50i_usb3_phy *phy = phy_get_drvdata(_phy);

        reset_control_assert(phy->reset);
        clk_disable_unprepare(phy->clk);

        return 0;
}

static const struct phy_ops sun50i_usb3_phy_ops = {
        .init           = sun50i_usb3_phy_init,
        .exit           = sun50i_usb3_phy_exit,
        .owner          = THIS_MODULE,
};

static int sun50i_usb3_phy_probe(struct platform_device *pdev)
{
        struct sun50i_usb3_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->clk = devm_clk_get(dev, NULL);
        if (IS_ERR(phy->clk)) {
                if (PTR_ERR(phy->clk) != -EPROBE_DEFER)
                        dev_err(dev, "failed to get phy clock\n");
                return PTR_ERR(phy->clk);
        }

        phy->reset = devm_reset_control_get(dev, NULL);
        if (IS_ERR(phy->reset)) {
                dev_err(dev, "failed to get reset control\n");
                return PTR_ERR(phy->reset);
        }

        phy->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(phy->regs))
                return PTR_ERR(phy->regs);

        phy->phy = devm_phy_create(dev, NULL, &sun50i_usb3_phy_ops);
        if (IS_ERR(phy->phy)) {
                dev_err(dev, "failed to create PHY\n");
                return PTR_ERR(phy->phy);
        }

        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 sun50i_usb3_phy_of_match[] = {
        { .compatible = "allwinner,sun50i-h6-usb3-phy" },
        { },
};
MODULE_DEVICE_TABLE(of, sun50i_usb3_phy_of_match);

static struct platform_driver sun50i_usb3_phy_driver = {
        .probe  = sun50i_usb3_phy_probe,
        .driver = {
                .of_match_table = sun50i_usb3_phy_of_match,
                .name  = "sun50i-usb3-phy",
        }
};
module_platform_driver(sun50i_usb3_phy_driver);

MODULE_DESCRIPTION("Allwinner H6 USB 3.0 phy driver");
MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
MODULE_LICENSE("GPL");