root/drivers/phy/amlogic/phy-meson-gxl-usb2.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Meson GXL and GXM USB2 PHY driver
 *
 * Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>

/* bits [31:27] are read-only */
#define U2P_R0                                                  0x0
        #define U2P_R0_BYPASS_SEL                               BIT(0)
        #define U2P_R0_BYPASS_DM_EN                             BIT(1)
        #define U2P_R0_BYPASS_DP_EN                             BIT(2)
        #define U2P_R0_TXBITSTUFF_ENH                           BIT(3)
        #define U2P_R0_TXBITSTUFF_EN                            BIT(4)
        #define U2P_R0_DM_PULLDOWN                              BIT(5)
        #define U2P_R0_DP_PULLDOWN                              BIT(6)
        #define U2P_R0_DP_VBUS_VLD_EXT_SEL                      BIT(7)
        #define U2P_R0_DP_VBUS_VLD_EXT                          BIT(8)
        #define U2P_R0_ADP_PRB_EN                               BIT(9)
        #define U2P_R0_ADP_DISCHARGE                            BIT(10)
        #define U2P_R0_ADP_CHARGE                               BIT(11)
        #define U2P_R0_DRV_VBUS                                 BIT(12)
        #define U2P_R0_ID_PULLUP                                BIT(13)
        #define U2P_R0_LOOPBACK_EN_B                            BIT(14)
        #define U2P_R0_OTG_DISABLE                              BIT(15)
        #define U2P_R0_COMMON_ONN                               BIT(16)
        #define U2P_R0_FSEL_MASK                                GENMASK(19, 17)
        #define U2P_R0_REF_CLK_SEL_MASK                         GENMASK(21, 20)
        #define U2P_R0_POWER_ON_RESET                           BIT(22)
        #define U2P_R0_V_ATE_TEST_EN_B_MASK                     GENMASK(24, 23)
        #define U2P_R0_ID_SET_ID_DQ                             BIT(25)
        #define U2P_R0_ATE_RESET                                BIT(26)
        #define U2P_R0_FSV_MINUS                                BIT(27)
        #define U2P_R0_FSV_PLUS                                 BIT(28)
        #define U2P_R0_BYPASS_DM_DATA                           BIT(29)
        #define U2P_R0_BYPASS_DP_DATA                           BIT(30)

#define U2P_R1                                                  0x4
        #define U2P_R1_BURN_IN_TEST                             BIT(0)
        #define U2P_R1_ACA_ENABLE                               BIT(1)
        #define U2P_R1_DCD_ENABLE                               BIT(2)
        #define U2P_R1_VDAT_SRC_EN_B                            BIT(3)
        #define U2P_R1_VDAT_DET_EN_B                            BIT(4)
        #define U2P_R1_CHARGES_SEL                              BIT(5)
        #define U2P_R1_TX_PREEMP_PULSE_TUNE                     BIT(6)
        #define U2P_R1_TX_PREEMP_AMP_TUNE_MASK                  GENMASK(8, 7)
        #define U2P_R1_TX_RES_TUNE_MASK                         GENMASK(10, 9)
        #define U2P_R1_TX_RISE_TUNE_MASK                        GENMASK(12, 11)
        #define U2P_R1_TX_VREF_TUNE_MASK                        GENMASK(16, 13)
        #define U2P_R1_TX_FSLS_TUNE_MASK                        GENMASK(20, 17)
        #define U2P_R1_TX_HSXV_TUNE_MASK                        GENMASK(22, 21)
        #define U2P_R1_OTG_TUNE_MASK                            GENMASK(25, 23)
        #define U2P_R1_SQRX_TUNE_MASK                           GENMASK(28, 26)
        #define U2P_R1_COMP_DIS_TUNE_MASK                       GENMASK(31, 29)

/* bits [31:14] are read-only */
#define U2P_R2                                                  0x8
        #define U2P_R2_TESTDATA_IN_MASK                         GENMASK(7, 0)
        #define U2P_R2_TESTADDR_MASK                            GENMASK(11, 8)
        #define U2P_R2_TESTDATA_OUT_SEL                         BIT(12)
        #define U2P_R2_TESTCLK                                  BIT(13)
        #define U2P_R2_TESTDATA_OUT_MASK                        GENMASK(17, 14)
        #define U2P_R2_ACA_PIN_RANGE_C                          BIT(18)
        #define U2P_R2_ACA_PIN_RANGE_B                          BIT(19)
        #define U2P_R2_ACA_PIN_RANGE_A                          BIT(20)
        #define U2P_R2_ACA_PIN_GND                              BIT(21)
        #define U2P_R2_ACA_PIN_FLOAT                            BIT(22)
        #define U2P_R2_CHARGE_DETECT                            BIT(23)
        #define U2P_R2_DEVICE_SESSION_VALID                     BIT(24)
        #define U2P_R2_ADP_PROBE                                BIT(25)
        #define U2P_R2_ADP_SENSE                                BIT(26)
        #define U2P_R2_SESSION_END                              BIT(27)
        #define U2P_R2_VBUS_VALID                               BIT(28)
        #define U2P_R2_B_VALID                                  BIT(29)
        #define U2P_R2_A_VALID                                  BIT(30)
        #define U2P_R2_ID_DIG                                   BIT(31)

#define U2P_R3                                                  0xc

#define RESET_COMPLETE_TIME                             500

struct phy_meson_gxl_usb2_priv {
        struct regmap           *regmap;
        enum phy_mode           mode;
        int                     is_enabled;
        struct clk              *clk;
        struct reset_control    *reset;
};

static const struct regmap_config phy_meson_gxl_usb2_regmap_conf = {
        .reg_bits = 8,
        .val_bits = 32,
        .reg_stride = 4,
        .max_register = U2P_R3,
};

static int phy_meson_gxl_usb2_init(struct phy *phy)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
        int ret;

        ret = reset_control_reset(priv->reset);
        if (ret)
                return ret;

        ret = clk_prepare_enable(priv->clk);
        if (ret) {
                reset_control_rearm(priv->reset);
                return ret;
        }

        return 0;
}

static int phy_meson_gxl_usb2_exit(struct phy *phy)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);

        clk_disable_unprepare(priv->clk);
        reset_control_rearm(priv->reset);

        return 0;
}

static int phy_meson_gxl_usb2_reset(struct phy *phy)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);

        if (priv->is_enabled) {
                /* reset the PHY and wait until settings are stabilized */
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
                                   U2P_R0_POWER_ON_RESET);
                udelay(RESET_COMPLETE_TIME);
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
                                   0);
                udelay(RESET_COMPLETE_TIME);
        }

        return 0;
}

static int phy_meson_gxl_usb2_set_mode(struct phy *phy,
                                       enum phy_mode mode, int submode)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);

        switch (mode) {
        case PHY_MODE_USB_HOST:
        case PHY_MODE_USB_OTG:
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DM_PULLDOWN,
                                   U2P_R0_DM_PULLDOWN);
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DP_PULLDOWN,
                                   U2P_R0_DP_PULLDOWN);
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_ID_PULLUP,
                                   U2P_R0_ID_PULLUP);
                break;

        case PHY_MODE_USB_DEVICE:
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DM_PULLDOWN,
                                   0);
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DP_PULLDOWN,
                                   0);
                regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_ID_PULLUP,
                                   U2P_R0_ID_PULLUP);
                break;

        default:
                return -EINVAL;
        }

        phy_meson_gxl_usb2_reset(phy);

        priv->mode = mode;

        return 0;
}

static int phy_meson_gxl_usb2_power_off(struct phy *phy)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);

        priv->is_enabled = 0;

        /* power off the PHY by putting it into reset mode */
        regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
                           U2P_R0_POWER_ON_RESET);

        return 0;
}

static int phy_meson_gxl_usb2_power_on(struct phy *phy)
{
        struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
        int ret;

        priv->is_enabled = 1;

        /* power on the PHY by taking it out of reset mode */
        regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET, 0);

        ret = phy_meson_gxl_usb2_set_mode(phy, priv->mode, 0);
        if (ret) {
                phy_meson_gxl_usb2_power_off(phy);

                dev_err(&phy->dev, "Failed to initialize PHY with mode %d\n",
                        priv->mode);
                return ret;
        }

        return 0;
}

static const struct phy_ops phy_meson_gxl_usb2_ops = {
        .init           = phy_meson_gxl_usb2_init,
        .exit           = phy_meson_gxl_usb2_exit,
        .power_on       = phy_meson_gxl_usb2_power_on,
        .power_off      = phy_meson_gxl_usb2_power_off,
        .set_mode       = phy_meson_gxl_usb2_set_mode,
        .reset          = phy_meson_gxl_usb2_reset,
        .owner          = THIS_MODULE,
};

static int phy_meson_gxl_usb2_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct phy_provider *phy_provider;
        struct phy_meson_gxl_usb2_priv *priv;
        struct phy *phy;
        void __iomem *base;

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

        platform_set_drvdata(pdev, priv);

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

        /* start in host mode */
        priv->mode = PHY_MODE_USB_HOST;

        priv->regmap = devm_regmap_init_mmio(dev, base,
                                             &phy_meson_gxl_usb2_regmap_conf);
        if (IS_ERR(priv->regmap))
                return PTR_ERR(priv->regmap);

        priv->clk = devm_clk_get_optional(dev, "phy");
        if (IS_ERR(priv->clk))
                return PTR_ERR(priv->clk);

        priv->reset = devm_reset_control_get_optional_shared(dev, "phy");
        if (IS_ERR(priv->reset))
                return PTR_ERR(priv->reset);

        phy = devm_phy_create(dev, NULL, &phy_meson_gxl_usb2_ops);
        if (IS_ERR(phy))
                return dev_err_probe(dev, PTR_ERR(phy),
                                     "failed to create PHY\n");

        phy_set_drvdata(phy, priv);

        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 phy_meson_gxl_usb2_of_match[] = {
        { .compatible = "amlogic,meson-gxl-usb2-phy", },
        { },
};
MODULE_DEVICE_TABLE(of, phy_meson_gxl_usb2_of_match);

static struct platform_driver phy_meson_gxl_usb2_driver = {
        .probe  = phy_meson_gxl_usb2_probe,
        .driver = {
                .name           = "phy-meson-gxl-usb2",
                .of_match_table = phy_meson_gxl_usb2_of_match,
        },
};
module_platform_driver(phy_meson_gxl_usb2_driver);

MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
MODULE_DESCRIPTION("Meson GXL and GXM USB2 PHY driver");
MODULE_LICENSE("GPL v2");