// SPDX-License-Identifier: GPL-2.0
/*
 * Renesas R-Car Gen3 for USB3.0 PHY driver
 *
 * Copyright (C) 2017 Renesas Electronics Corporation
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#define USB30_CLKSET0           0x034
#define USB30_CLKSET1           0x036
#define USB30_SSC_SET           0x038
#define USB30_PHY_ENABLE        0x060
#define USB30_VBUS_EN           0x064

/* USB30_CLKSET0 */
#define CLKSET0_PRIVATE                 0x05c0
#define CLKSET0_USB30_FSEL_USB_EXTAL    0x0002

/* USB30_CLKSET1 */
#define CLKSET1_USB30_PLL_MULTI_SHIFT           6
#define CLKSET1_USB30_PLL_MULTI_USB_EXTAL       (0x64 << \
                                                 CLKSET1_USB30_PLL_MULTI_SHIFT)
#define CLKSET1_PHYRESET        BIT(4)  /* 1: reset */
#define CLKSET1_REF_CLKDIV      BIT(3)  /* 1: USB_EXTAL */
#define CLKSET1_PRIVATE_2_1     BIT(1)  /* Write B'01 */
#define CLKSET1_REF_CLK_SEL     BIT(0)  /* 1: USB3S0_CLK_P */

/* USB30_SSC_SET */
#define SSC_SET_SSC_EN          BIT(12)
#define SSC_SET_RANGE_SHIFT     9
#define SSC_SET_RANGE_4980      (0x0 << SSC_SET_RANGE_SHIFT)
#define SSC_SET_RANGE_4492      (0x1 << SSC_SET_RANGE_SHIFT)
#define SSC_SET_RANGE_4003      (0x2 << SSC_SET_RANGE_SHIFT)

/* USB30_PHY_ENABLE */
#define PHY_ENABLE_RESET_EN     BIT(4)

/* USB30_VBUS_EN */
#define VBUS_EN_VBUS_EN         BIT(1)

struct rcar_gen3_usb3 {
        void __iomem *base;
        struct phy *phy;
        u32 ssc_range;
        bool usb3s_clk;
        bool usb_extal;
};

static void write_clkset1_for_usb_extal(struct rcar_gen3_usb3 *r, bool reset)
{
        u16 val = CLKSET1_USB30_PLL_MULTI_USB_EXTAL |
                  CLKSET1_REF_CLKDIV | CLKSET1_PRIVATE_2_1;

        if (reset)
                val |= CLKSET1_PHYRESET;

        writew(val, r->base + USB30_CLKSET1);
}

static void rcar_gen3_phy_usb3_enable_ssc(struct rcar_gen3_usb3 *r)
{
        u16 val = SSC_SET_SSC_EN;

        switch (r->ssc_range) {
        case 4980:
                val |= SSC_SET_RANGE_4980;
                break;
        case 4492:
                val |= SSC_SET_RANGE_4492;
                break;
        case 4003:
                val |= SSC_SET_RANGE_4003;
                break;
        default:
                dev_err(&r->phy->dev, "%s: unsupported range (%x)\n", __func__,
                        r->ssc_range);
                return;
        }

        writew(val, r->base + USB30_SSC_SET);
}

static void rcar_gen3_phy_usb3_select_usb_extal(struct rcar_gen3_usb3 *r)
{
        write_clkset1_for_usb_extal(r, false);
        if (r->ssc_range)
                rcar_gen3_phy_usb3_enable_ssc(r);
        writew(CLKSET0_PRIVATE | CLKSET0_USB30_FSEL_USB_EXTAL,
               r->base + USB30_CLKSET0);
        writew(PHY_ENABLE_RESET_EN, r->base + USB30_PHY_ENABLE);
        write_clkset1_for_usb_extal(r, true);
        usleep_range(10, 20);
        write_clkset1_for_usb_extal(r, false);
}

static int rcar_gen3_phy_usb3_init(struct phy *p)
{
        struct rcar_gen3_usb3 *r = phy_get_drvdata(p);

        dev_vdbg(&r->phy->dev, "%s: enter (%d, %d, %d)\n", __func__,
                 r->usb3s_clk, r->usb_extal, r->ssc_range);

        if (!r->usb3s_clk && r->usb_extal)
                rcar_gen3_phy_usb3_select_usb_extal(r);

        /* Enables VBUS detection anyway */
        writew(VBUS_EN_VBUS_EN, r->base + USB30_VBUS_EN);

        return 0;
}

static const struct phy_ops rcar_gen3_phy_usb3_ops = {
        .init           = rcar_gen3_phy_usb3_init,
        .owner          = THIS_MODULE,
};

static const struct of_device_id rcar_gen3_phy_usb3_match_table[] = {
        { .compatible = "renesas,rcar-gen3-usb3-phy" },
        { }
};
MODULE_DEVICE_TABLE(of, rcar_gen3_phy_usb3_match_table);

static int rcar_gen3_phy_usb3_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct rcar_gen3_usb3 *r;
        struct phy_provider *provider;
        int ret = 0;
        struct clk *clk;

        if (!dev->of_node) {
                dev_err(dev, "This driver needs device tree\n");
                return -EINVAL;
        }

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

        r->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(r->base))
                return PTR_ERR(r->base);

        clk = devm_clk_get(dev, "usb3s_clk");
        if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
                r->usb3s_clk = !!clk_get_rate(clk);
                clk_disable_unprepare(clk);
        }
        clk = devm_clk_get(dev, "usb_extal");
        if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
                r->usb_extal = !!clk_get_rate(clk);
                clk_disable_unprepare(clk);
        }

        if (!r->usb3s_clk && !r->usb_extal) {
                dev_err(dev, "This driver needs usb3s_clk and/or usb_extal\n");
                ret = -EINVAL;
                goto error;
        }

        /*
         * devm_phy_create() will call pm_runtime_enable(&phy->dev);
         * And then, phy-core will manage runtime pm for this device.
         */
        pm_runtime_enable(dev);

        r->phy = devm_phy_create(dev, NULL, &rcar_gen3_phy_usb3_ops);
        if (IS_ERR(r->phy)) {
                dev_err(dev, "Failed to create USB3 PHY\n");
                ret = PTR_ERR(r->phy);
                goto error;
        }

        of_property_read_u32(dev->of_node, "renesas,ssc-range", &r->ssc_range);

        platform_set_drvdata(pdev, r);
        phy_set_drvdata(r->phy, r);

        provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
        if (IS_ERR(provider)) {
                dev_err(dev, "Failed to register PHY provider\n");
                ret = PTR_ERR(provider);
                goto error;
        }

        return 0;

error:
        pm_runtime_disable(dev);

        return ret;
}

static void rcar_gen3_phy_usb3_remove(struct platform_device *pdev)
{
        pm_runtime_disable(&pdev->dev);
}

static struct platform_driver rcar_gen3_phy_usb3_driver = {
        .driver = {
                .name = "phy_rcar_gen3_usb3",
                .of_match_table = rcar_gen3_phy_usb3_match_table,
        },
        .probe = rcar_gen3_phy_usb3_probe,
        .remove = rcar_gen3_phy_usb3_remove,
};
module_platform_driver(rcar_gen3_phy_usb3_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Renesas R-Car Gen3 USB 3.0 PHY");
MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");