/*
 * Copyright (c) 2017, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/slab.h>

#define QUSB2PHY_PLL_TEST               0x04
#define CLK_REF_SEL                     BIT(7)

#define QUSB2PHY_PLL_TUNE               0x08
#define QUSB2PHY_PLL_USER_CTL1          0x0c
#define QUSB2PHY_PLL_USER_CTL2          0x10
#define QUSB2PHY_PLL_AUTOPGM_CTL1       0x1c
#define QUSB2PHY_PLL_PWR_CTRL           0x18

#define QUSB2PHY_PLL_STATUS             0x38
#define PLL_LOCKED                      BIT(5)

#define QUSB2PHY_PORT_TUNE1             0x80
#define QUSB2PHY_PORT_TUNE2             0x84
#define QUSB2PHY_PORT_TUNE3             0x88
#define QUSB2PHY_PORT_TUNE4             0x8c
#define QUSB2PHY_PORT_TUNE5             0x90
#define QUSB2PHY_PORT_TEST2             0x9c

#define QUSB2PHY_PORT_POWERDOWN         0xb4
#define CLAMP_N_EN                      BIT(5)
#define FREEZIO_N                       BIT(1)
#define POWER_DOWN                      BIT(0)

#define QUSB2PHY_REFCLK_ENABLE          BIT(0)

#define PHY_CLK_SCHEME_SEL              BIT(0)

struct qusb2_phy_init_tbl {
        unsigned int offset;
        unsigned int val;
};

#define QUSB2_PHY_INIT_CFG(o, v) \
        {                       \
                .offset = o,    \
                .val = v,       \
        }

static const struct qusb2_phy_init_tbl msm8996_init_tbl[] = {
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE1, 0xf8),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE2, 0xb3),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE3, 0x83),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE4, 0xc0),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_TUNE, 0x30),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_USER_CTL1, 0x79),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_USER_CTL2, 0x21),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TEST2, 0x14),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_AUTOPGM_CTL1, 0x9f),
        QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_PWR_CTRL, 0x00),
};

struct qusb2_phy_cfg {
        const struct qusb2_phy_init_tbl *tbl;
        /* number of entries in the table */
        unsigned int tbl_num;
        /* offset to PHY_CLK_SCHEME register in TCSR map */
        unsigned int clk_scheme_offset;
};

static const struct qusb2_phy_cfg msm8996_phy_cfg = {
        .tbl = msm8996_init_tbl,
        .tbl_num = ARRAY_SIZE(msm8996_init_tbl),
};

static const char * const qusb2_phy_vreg_names[] = {
        "vdda-pll", "vdda-phy-dpdm",
};

#define QUSB2_NUM_VREGS         ARRAY_SIZE(qusb2_phy_vreg_names)

/**
 * struct qusb2_phy - structure holding qusb2 phy attributes
 *
 * @phy: generic phy
 * @base: iomapped memory space for qubs2 phy
 *
 * @cfg_ahb_clk: AHB2PHY interface clock
 * @ref_clk: phy reference clock
 * @iface_clk: phy interface clock
 * @phy_reset: phy reset control
 * @vregs: regulator supplies bulk data
 *
 * @tcsr: TCSR syscon register map
 * @cell: nvmem cell containing phy tuning value
 *
 * @cfg: phy config data
 * @has_se_clk_scheme: indicate if PHY has single-ended ref clock scheme
 */
struct qusb2_phy {
        struct phy *phy;
        void __iomem *base;

        struct clk *cfg_ahb_clk;
        struct clk *ref_clk;
        struct clk *iface_clk;
        struct reset_control *phy_reset;
        struct regulator_bulk_data vregs[QUSB2_NUM_VREGS];

        struct regmap *tcsr;
        struct nvmem_cell *cell;

        const struct qusb2_phy_cfg *cfg;
        bool has_se_clk_scheme;
};

static inline void qusb2_setbits(void __iomem *base, u32 offset, u32 val)
{
        u32 reg;

        reg = readl(base + offset);
        reg |= val;
        writel(reg, base + offset);

        /* Ensure above write is completed */
        readl(base + offset);
}

static inline void qusb2_clrbits(void __iomem *base, u32 offset, u32 val)
{
        u32 reg;

        reg = readl(base + offset);
        reg &= ~val;
        writel(reg, base + offset);

        /* Ensure above write is completed */
        readl(base + offset);
}

static inline
void qcom_qusb2_phy_configure(void __iomem *base,
                              const struct qusb2_phy_init_tbl tbl[], int num)
{
        int i;

        for (i = 0; i < num; i++)
                writel(tbl[i].val, base + tbl[i].offset);
}

/*
 * Fetches HS Tx tuning value from nvmem and sets the
 * QUSB2PHY_PORT_TUNE2 register.
 * For error case, skip setting the value and use the default value.
 */
static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy)
{
        struct device *dev = &qphy->phy->dev;
        u8 *val;

        /*
         * Read efuse register having TUNE2 parameter's high nibble.
         * If efuse register shows value as 0x0, or if we fail to find
         * a valid efuse register settings, then use default value
         * as 0xB for high nibble that we have already set while
         * configuring phy.
         */
        val = nvmem_cell_read(qphy->cell, NULL);
        if (IS_ERR(val) || !val[0]) {
                dev_dbg(dev, "failed to read a valid hs-tx trim value\n");
                return;
        }

        /* Fused TUNE2 value is the higher nibble only */
        qusb2_setbits(qphy->base, QUSB2PHY_PORT_TUNE2, val[0] << 0x4);
}

static int qusb2_phy_poweron(struct phy *phy)
{
        struct qusb2_phy *qphy = phy_get_drvdata(phy);
        int num = ARRAY_SIZE(qphy->vregs);
        int ret;

        dev_vdbg(&phy->dev, "%s(): Powering-on QUSB2 phy\n", __func__);

        /* turn on regulator supplies */
        ret = regulator_bulk_enable(num, qphy->vregs);
        if (ret)
                return ret;

        ret = clk_prepare_enable(qphy->iface_clk);
        if (ret) {
                dev_err(&phy->dev, "failed to enable iface_clk, %d\n", ret);
                regulator_bulk_disable(num, qphy->vregs);
                return ret;
        }

        return 0;
}

static int qusb2_phy_poweroff(struct phy *phy)
{
        struct qusb2_phy *qphy = phy_get_drvdata(phy);

        clk_disable_unprepare(qphy->iface_clk);

        regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);

        return 0;
}

static int qusb2_phy_init(struct phy *phy)
{
        struct qusb2_phy *qphy = phy_get_drvdata(phy);
        unsigned int val;
        unsigned int clk_scheme;
        int ret;

        dev_vdbg(&phy->dev, "%s(): Initializing QUSB2 phy\n", __func__);

        /* enable ahb interface clock to program phy */
        ret = clk_prepare_enable(qphy->cfg_ahb_clk);
        if (ret) {
                dev_err(&phy->dev, "failed to enable cfg ahb clock, %d\n", ret);
                return ret;
        }

        /* Perform phy reset */
        ret = reset_control_assert(qphy->phy_reset);
        if (ret) {
                dev_err(&phy->dev, "failed to assert phy_reset, %d\n", ret);
                goto disable_ahb_clk;
        }

        /* 100 us delay to keep PHY in reset mode */
        usleep_range(100, 150);

        ret = reset_control_deassert(qphy->phy_reset);
        if (ret) {
                dev_err(&phy->dev, "failed to de-assert phy_reset, %d\n", ret);
                goto disable_ahb_clk;
        }

        /* Disable the PHY */
        qusb2_setbits(qphy->base, QUSB2PHY_PORT_POWERDOWN,
                      CLAMP_N_EN | FREEZIO_N | POWER_DOWN);

        /* save reset value to override reference clock scheme later */
        val = readl(qphy->base + QUSB2PHY_PLL_TEST);

        qcom_qusb2_phy_configure(qphy->base, qphy->cfg->tbl,
                                 qphy->cfg->tbl_num);

        /* Set efuse value for tuning the PHY */
        qusb2_phy_set_tune2_param(qphy);

        /* Enable the PHY */
        qusb2_clrbits(qphy->base, QUSB2PHY_PORT_POWERDOWN, POWER_DOWN);

        /* Required to get phy pll lock successfully */
        usleep_range(150, 160);

        /* Default is single-ended clock on msm8996 */
        qphy->has_se_clk_scheme = true;
        /*
         * read TCSR_PHY_CLK_SCHEME register to check if single-ended
         * clock scheme is selected. If yes, then disable differential
         * ref_clk and use single-ended clock, otherwise use differential
         * ref_clk only.
         */
        if (qphy->tcsr) {
                ret = regmap_read(qphy->tcsr, qphy->cfg->clk_scheme_offset,
                                  &clk_scheme);
                if (ret) {
                        dev_err(&phy->dev, "failed to read clk scheme reg\n");
                        goto assert_phy_reset;
                }

                /* is it a differential clock scheme ? */
                if (!(clk_scheme & PHY_CLK_SCHEME_SEL)) {
                        dev_vdbg(&phy->dev, "%s(): select differential clk\n",
                                 __func__);
                        qphy->has_se_clk_scheme = false;
                } else {
                        dev_vdbg(&phy->dev, "%s(): select single-ended clk\n",
                                 __func__);
                }
        }

        if (!qphy->has_se_clk_scheme) {
                val &= ~CLK_REF_SEL;
                ret = clk_prepare_enable(qphy->ref_clk);
                if (ret) {
                        dev_err(&phy->dev, "failed to enable ref clk, %d\n",
                                ret);
                        goto assert_phy_reset;
                }
        } else {
                val |= CLK_REF_SEL;
        }

        writel(val, qphy->base + QUSB2PHY_PLL_TEST);

        /* ensure above write is through */
        readl(qphy->base + QUSB2PHY_PLL_TEST);

        /* Required to get phy pll lock successfully */
        usleep_range(100, 110);

        val = readb(qphy->base + QUSB2PHY_PLL_STATUS);
        if (!(val & PLL_LOCKED)) {
                dev_err(&phy->dev,
                        "QUSB2PHY pll lock failed: status reg = %x\n", val);
                ret = -EBUSY;
                goto disable_ref_clk;
        }

        return 0;

disable_ref_clk:
        if (!qphy->has_se_clk_scheme)
                clk_disable_unprepare(qphy->ref_clk);
assert_phy_reset:
        reset_control_assert(qphy->phy_reset);
disable_ahb_clk:
        clk_disable_unprepare(qphy->cfg_ahb_clk);
        return ret;
}

static int qusb2_phy_exit(struct phy *phy)
{
        struct qusb2_phy *qphy = phy_get_drvdata(phy);

        /* Disable the PHY */
        qusb2_setbits(qphy->base, QUSB2PHY_PORT_POWERDOWN,
                      CLAMP_N_EN | FREEZIO_N | POWER_DOWN);

        if (!qphy->has_se_clk_scheme)
                clk_disable_unprepare(qphy->ref_clk);

        reset_control_assert(qphy->phy_reset);

        clk_disable_unprepare(qphy->cfg_ahb_clk);

        return 0;
}

static const struct phy_ops qusb2_phy_gen_ops = {
        .init           = qusb2_phy_init,
        .exit           = qusb2_phy_exit,
        .power_on       = qusb2_phy_poweron,
        .power_off      = qusb2_phy_poweroff,
        .owner          = THIS_MODULE,
};

static const struct of_device_id qusb2_phy_of_match_table[] = {
        {
                .compatible     = "qcom,msm8996-qusb2-phy",
                .data           = &msm8996_phy_cfg,
        },
        { },
};
MODULE_DEVICE_TABLE(of, qusb2_phy_of_match_table);

static int qusb2_phy_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct qusb2_phy *qphy;
        struct phy_provider *phy_provider;
        struct phy *generic_phy;
        struct resource *res;
        int ret, i;
        int num;

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

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        qphy->base = devm_ioremap_resource(dev, res);
        if (IS_ERR(qphy->base))
                return PTR_ERR(qphy->base);

        qphy->cfg_ahb_clk = devm_clk_get(dev, "cfg_ahb");
        if (IS_ERR(qphy->cfg_ahb_clk)) {
                ret = PTR_ERR(qphy->cfg_ahb_clk);
                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "failed to get cfg ahb clk, %d\n", ret);
                return ret;
        }

        qphy->ref_clk = devm_clk_get(dev, "ref");
        if (IS_ERR(qphy->ref_clk)) {
                ret = PTR_ERR(qphy->ref_clk);
                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "failed to get ref clk, %d\n", ret);
                return ret;
        }

        qphy->iface_clk = devm_clk_get(dev, "iface");
        if (IS_ERR(qphy->iface_clk)) {
                ret = PTR_ERR(qphy->iface_clk);
                if (ret == -EPROBE_DEFER)
                        return ret;
                qphy->iface_clk = NULL;
                dev_dbg(dev, "failed to get iface clk, %d\n", ret);
        }

        qphy->phy_reset = devm_reset_control_get_by_index(&pdev->dev, 0);
        if (IS_ERR(qphy->phy_reset)) {
                dev_err(dev, "failed to get phy core reset\n");
                return PTR_ERR(qphy->phy_reset);
        }

        num = ARRAY_SIZE(qphy->vregs);
        for (i = 0; i < num; i++)
                qphy->vregs[i].supply = qusb2_phy_vreg_names[i];

        ret = devm_regulator_bulk_get(dev, num, qphy->vregs);
        if (ret) {
                dev_err(dev, "failed to get regulator supplies\n");
                return ret;
        }

        /* Get the specific init parameters of QMP phy */
        qphy->cfg = of_device_get_match_data(dev);

        qphy->tcsr = syscon_regmap_lookup_by_phandle(dev->of_node,
                                                        "qcom,tcsr-syscon");
        if (IS_ERR(qphy->tcsr)) {
                dev_dbg(dev, "failed to lookup TCSR regmap\n");
                qphy->tcsr = NULL;
        }

        qphy->cell = devm_nvmem_cell_get(dev, NULL);
        if (IS_ERR(qphy->cell)) {
                if (PTR_ERR(qphy->cell) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;
                qphy->cell = NULL;
                dev_dbg(dev, "failed to lookup tune2 hstx trim value\n");
        }

        generic_phy = devm_phy_create(dev, NULL, &qusb2_phy_gen_ops);
        if (IS_ERR(generic_phy)) {
                ret = PTR_ERR(generic_phy);
                dev_err(dev, "failed to create phy, %d\n", ret);
                return ret;
        }
        qphy->phy = generic_phy;

        dev_set_drvdata(dev, qphy);
        phy_set_drvdata(generic_phy, qphy);

        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
        if (!IS_ERR(phy_provider))
                dev_info(dev, "Registered Qcom-QUSB2 phy\n");

        return PTR_ERR_OR_ZERO(phy_provider);
}

static struct platform_driver qusb2_phy_driver = {
        .probe          = qusb2_phy_probe,
        .driver = {
                .name   = "qcom-qusb2-phy",
                .of_match_table = qusb2_phy_of_match_table,
        },
};

module_platform_driver(qusb2_phy_driver);

MODULE_AUTHOR("Vivek Gautam <vivek.gautam@codeaurora.org>");
MODULE_DESCRIPTION("Qualcomm QUSB2 PHY driver");
MODULE_LICENSE("GPL v2");