/*
 * Copyright (C) 2014 STMicroelectronics – All Rights Reserved
 *
 * STMicroelectronics PHY driver MiPHY365 (for SoC STiH416).
 *
 * Authors: Alexandre Torgue <alexandre.torgue@st.com>
 *          Lee Jones <lee.jones@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2, as
 * published by the Free Software Foundation.
 *
 */

#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/clk.h>
#include <linux/phy/phy.h>
#include <linux/delay.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>

#include <dt-bindings/phy/phy.h>

#define HFC_TIMEOUT             100

#define SYSCFG_SELECT_SATA_MASK BIT(1)
#define SYSCFG_SELECT_SATA_POS  1

/* MiPHY365x register definitions */
#define RESET_REG               0x00
#define RST_PLL                 BIT(1)
#define RST_PLL_CAL             BIT(2)
#define RST_RX                  BIT(4)
#define RST_MACRO               BIT(7)

#define STATUS_REG              0x01
#define IDLL_RDY                BIT(0)
#define PLL_RDY                 BIT(1)
#define DES_BIT_LOCK            BIT(2)
#define DES_SYMBOL_LOCK         BIT(3)

#define CTRL_REG                0x02
#define TERM_EN                 BIT(0)
#define PCI_EN                  BIT(2)
#define DES_BIT_LOCK_EN         BIT(3)
#define TX_POL                  BIT(5)

#define INT_CTRL_REG            0x03

#define BOUNDARY1_REG           0x10
#define SPDSEL_SEL              BIT(0)

#define BOUNDARY3_REG           0x12
#define TX_SPDSEL_GEN1_VAL      0
#define TX_SPDSEL_GEN2_VAL      0x01
#define TX_SPDSEL_GEN3_VAL      0x02
#define RX_SPDSEL_GEN1_VAL      0
#define RX_SPDSEL_GEN2_VAL      (0x01 << 3)
#define RX_SPDSEL_GEN3_VAL      (0x02 << 3)

#define PCIE_REG                0x16

#define BUF_SEL_REG             0x20
#define CONF_GEN_SEL_GEN3       0x02
#define CONF_GEN_SEL_GEN2       0x01
#define PD_VDDTFILTER           BIT(4)

#define TXBUF1_REG              0x21
#define SWING_VAL               0x04
#define SWING_VAL_GEN1          0x03
#define PREEMPH_VAL             (0x3 << 5)

#define TXBUF2_REG              0x22
#define TXSLEW_VAL              0x2
#define TXSLEW_VAL_GEN1         0x4

#define RXBUF_OFFSET_CTRL_REG   0x23

#define RXBUF_REG               0x25
#define SDTHRES_VAL             0x01
#define EQ_ON3                  (0x03 << 4)
#define EQ_ON1                  (0x01 << 4)

#define COMP_CTRL1_REG          0x40
#define START_COMSR             BIT(0)
#define START_COMZC             BIT(1)
#define COMSR_DONE              BIT(2)
#define COMZC_DONE              BIT(3)
#define COMP_AUTO_LOAD          BIT(4)

#define COMP_CTRL2_REG          0x41
#define COMP_2MHZ_RAT_GEN1      0x1e
#define COMP_2MHZ_RAT           0xf

#define COMP_CTRL3_REG          0x42
#define COMSR_COMP_REF          0x33

#define COMP_IDLL_REG           0x47
#define COMZC_IDLL              0x2a

#define PLL_CTRL1_REG           0x50
#define PLL_START_CAL           BIT(0)
#define BUF_EN                  BIT(2)
#define SYNCHRO_TX              BIT(3)
#define SSC_EN                  BIT(6)
#define CONFIG_PLL              BIT(7)

#define PLL_CTRL2_REG           0x51
#define BYPASS_PLL_CAL          BIT(1)

#define PLL_RAT_REG             0x52

#define PLL_SSC_STEP_MSB_REG    0x56
#define PLL_SSC_STEP_MSB_VAL    0x03

#define PLL_SSC_STEP_LSB_REG    0x57
#define PLL_SSC_STEP_LSB_VAL    0x63

#define PLL_SSC_PER_MSB_REG     0x58
#define PLL_SSC_PER_MSB_VAL     0

#define PLL_SSC_PER_LSB_REG     0x59
#define PLL_SSC_PER_LSB_VAL     0xf1

#define IDLL_TEST_REG           0x72
#define START_CLK_HF            BIT(6)

#define DES_BITLOCK_REG         0x86
#define BIT_LOCK_LEVEL          0x01
#define BIT_LOCK_CNT_512        (0x03 << 5)

struct miphy365x_phy {
        struct phy *phy;
        void __iomem *base;
        bool pcie_tx_pol_inv;
        bool sata_tx_pol_inv;
        u32 sata_gen;
        u32 ctrlreg;
        u8 type;
};

struct miphy365x_dev {
        struct device *dev;
        struct regmap *regmap;
        struct mutex miphy_mutex;
        struct miphy365x_phy **phys;
        int nphys;
};

/*
 * These values are represented in Device tree. They are considered to be ABI
 * and although they can be extended any existing values must not change.
 */
enum miphy_sata_gen {
        SATA_GEN1 = 1,
        SATA_GEN2,
        SATA_GEN3
};

static u8 rx_tx_spd[] = {
        0, /* GEN0 doesn't exist. */
        TX_SPDSEL_GEN1_VAL | RX_SPDSEL_GEN1_VAL,
        TX_SPDSEL_GEN2_VAL | RX_SPDSEL_GEN2_VAL,
        TX_SPDSEL_GEN3_VAL | RX_SPDSEL_GEN3_VAL
};

/*
 * This function selects the system configuration,
 * either two SATA, one SATA and one PCIe, or two PCIe lanes.
 */
static int miphy365x_set_path(struct miphy365x_phy *miphy_phy,
                              struct miphy365x_dev *miphy_dev)
{
        bool sata = (miphy_phy->type == PHY_TYPE_SATA);

        return regmap_update_bits(miphy_dev->regmap,
                                  miphy_phy->ctrlreg,
                                  SYSCFG_SELECT_SATA_MASK,
                                  sata << SYSCFG_SELECT_SATA_POS);
}

static int miphy365x_init_pcie_port(struct miphy365x_phy *miphy_phy,
                                    struct miphy365x_dev *miphy_dev)
{
        u8 val;

        if (miphy_phy->pcie_tx_pol_inv) {
                /* Invert Tx polarity and clear pci_txdetect_pol bit */
                val = TERM_EN | PCI_EN | DES_BIT_LOCK_EN | TX_POL;
                writeb_relaxed(val, miphy_phy->base + CTRL_REG);
                writeb_relaxed(0x00, miphy_phy->base + PCIE_REG);
        }

        return 0;
}

static inline int miphy365x_hfc_not_rdy(struct miphy365x_phy *miphy_phy,
                                        struct miphy365x_dev *miphy_dev)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(HFC_TIMEOUT);
        u8 mask = IDLL_RDY | PLL_RDY;
        u8 regval;

        do {
                regval = readb_relaxed(miphy_phy->base + STATUS_REG);
                if (!(regval & mask))
                        return 0;

                usleep_range(2000, 2500);
        } while (time_before(jiffies, timeout));

        dev_err(miphy_dev->dev, "HFC ready timeout!\n");
        return -EBUSY;
}

static inline int miphy365x_rdy(struct miphy365x_phy *miphy_phy,
                                struct miphy365x_dev *miphy_dev)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(HFC_TIMEOUT);
        u8 mask = IDLL_RDY | PLL_RDY;
        u8 regval;

        do {
                regval = readb_relaxed(miphy_phy->base + STATUS_REG);
                if ((regval & mask) == mask)
                        return 0;

                usleep_range(2000, 2500);
        } while (time_before(jiffies, timeout));

        dev_err(miphy_dev->dev, "PHY not ready timeout!\n");
        return -EBUSY;
}

static inline void miphy365x_set_comp(struct miphy365x_phy *miphy_phy,
                                      struct miphy365x_dev *miphy_dev)
{
        u8 val, mask;

        if (miphy_phy->sata_gen == SATA_GEN1)
                writeb_relaxed(COMP_2MHZ_RAT_GEN1,
                               miphy_phy->base + COMP_CTRL2_REG);
        else
                writeb_relaxed(COMP_2MHZ_RAT,
                               miphy_phy->base + COMP_CTRL2_REG);

        if (miphy_phy->sata_gen != SATA_GEN3) {
                writeb_relaxed(COMSR_COMP_REF,
                               miphy_phy->base + COMP_CTRL3_REG);
                /*
                 * Force VCO current to value defined by address 0x5A
                 * and disable PCIe100Mref bit
                 * Enable auto load compensation for pll_i_bias
                 */
                writeb_relaxed(BYPASS_PLL_CAL, miphy_phy->base + PLL_CTRL2_REG);
                writeb_relaxed(COMZC_IDLL, miphy_phy->base + COMP_IDLL_REG);
        }

        /*
         * Force restart compensation and enable auto load
         * for Comzc_Tx, Comzc_Rx and Comsr on macro
         */
        val = START_COMSR | START_COMZC | COMP_AUTO_LOAD;
        writeb_relaxed(val, miphy_phy->base + COMP_CTRL1_REG);

        mask = COMSR_DONE | COMZC_DONE;
        while ((readb_relaxed(miphy_phy->base + COMP_CTRL1_REG) & mask) != mask)
                cpu_relax();
}

static inline void miphy365x_set_ssc(struct miphy365x_phy *miphy_phy,
                                     struct miphy365x_dev *miphy_dev)
{
        u8 val;

        /*
         * SSC Settings. SSC will be enabled through Link
         * SSC Ampl. = 0.4%
         * SSC Freq = 31KHz
         */
        writeb_relaxed(PLL_SSC_STEP_MSB_VAL,
                       miphy_phy->base + PLL_SSC_STEP_MSB_REG);
        writeb_relaxed(PLL_SSC_STEP_LSB_VAL,
                       miphy_phy->base + PLL_SSC_STEP_LSB_REG);
        writeb_relaxed(PLL_SSC_PER_MSB_VAL,
                       miphy_phy->base + PLL_SSC_PER_MSB_REG);
        writeb_relaxed(PLL_SSC_PER_LSB_VAL,
                       miphy_phy->base + PLL_SSC_PER_LSB_REG);

        /* SSC Settings complete */
        if (miphy_phy->sata_gen == SATA_GEN1) {
                val = PLL_START_CAL | BUF_EN | SYNCHRO_TX | CONFIG_PLL;
                writeb_relaxed(val, miphy_phy->base + PLL_CTRL1_REG);
        } else {
                val = SSC_EN | PLL_START_CAL | BUF_EN | SYNCHRO_TX | CONFIG_PLL;
                writeb_relaxed(val, miphy_phy->base + PLL_CTRL1_REG);
        }
}

static int miphy365x_init_sata_port(struct miphy365x_phy *miphy_phy,
                                    struct miphy365x_dev *miphy_dev)
{
        int ret;
        u8 val;

        /*
         * Force PHY macro reset, PLL calibration reset, PLL reset
         * and assert Deserializer Reset
         */
        val = RST_PLL | RST_PLL_CAL | RST_RX | RST_MACRO;
        writeb_relaxed(val, miphy_phy->base + RESET_REG);

        if (miphy_phy->sata_tx_pol_inv)
                writeb_relaxed(TX_POL, miphy_phy->base + CTRL_REG);

        /*
         * Force macro1 to use rx_lspd, tx_lspd
         * Force Rx_Clock on first I-DLL phase
         * Force Des in HP mode on macro, rx_lspd, tx_lspd for Gen2/3
         */
        writeb_relaxed(SPDSEL_SEL, miphy_phy->base + BOUNDARY1_REG);
        writeb_relaxed(START_CLK_HF, miphy_phy->base + IDLL_TEST_REG);
        val = rx_tx_spd[miphy_phy->sata_gen];
        writeb_relaxed(val, miphy_phy->base + BOUNDARY3_REG);

        /* Wait for HFC_READY = 0 */
        ret = miphy365x_hfc_not_rdy(miphy_phy, miphy_dev);
        if (ret)
                return ret;

        /* Compensation Recalibration */
        miphy365x_set_comp(miphy_phy, miphy_dev);

        switch (miphy_phy->sata_gen) {
        case SATA_GEN3:
                /*
                 * TX Swing target 550-600mv peak to peak diff
                 * Tx Slew target 90-110ps rising/falling time
                 * Rx Eq ON3, Sigdet threshold SDTH1
                 */
                val = PD_VDDTFILTER | CONF_GEN_SEL_GEN3;
                writeb_relaxed(val, miphy_phy->base + BUF_SEL_REG);
                val = SWING_VAL | PREEMPH_VAL;
                writeb_relaxed(val, miphy_phy->base + TXBUF1_REG);
                writeb_relaxed(TXSLEW_VAL, miphy_phy->base + TXBUF2_REG);
                writeb_relaxed(0x00, miphy_phy->base + RXBUF_OFFSET_CTRL_REG);
                val = SDTHRES_VAL | EQ_ON3;
                writeb_relaxed(val, miphy_phy->base + RXBUF_REG);
                break;
        case SATA_GEN2:
                /*
                 * conf gen sel=0x1 to program Gen2 banked registers
                 * VDDT filter ON
                 * Tx Swing target 550-600mV peak-to-peak diff
                 * Tx Slew target 90-110 ps rising/falling time
                 * RX Equalization ON1, Sigdet threshold SDTH1
                 */
                writeb_relaxed(CONF_GEN_SEL_GEN2,
                               miphy_phy->base + BUF_SEL_REG);
                writeb_relaxed(SWING_VAL, miphy_phy->base + TXBUF1_REG);
                writeb_relaxed(TXSLEW_VAL, miphy_phy->base + TXBUF2_REG);
                val = SDTHRES_VAL | EQ_ON1;
                writeb_relaxed(val, miphy_phy->base + RXBUF_REG);
                break;
        case SATA_GEN1:
                /*
                 * conf gen sel = 00b to program Gen1 banked registers
                 * VDDT filter ON
                 * Tx Swing target 500-550mV peak-to-peak diff
                 * Tx Slew target120-140 ps rising/falling time
                 */
                writeb_relaxed(PD_VDDTFILTER, miphy_phy->base + BUF_SEL_REG);
                writeb_relaxed(SWING_VAL_GEN1, miphy_phy->base + TXBUF1_REG);
                writeb_relaxed(TXSLEW_VAL_GEN1, miphy_phy->base + TXBUF2_REG);
                break;
        default:
                break;
        }

        /* Force Macro1 in partial mode & release pll cal reset */
        writeb_relaxed(RST_RX, miphy_phy->base + RESET_REG);
        usleep_range(100, 150);

        miphy365x_set_ssc(miphy_phy, miphy_dev);

        /* Wait for phy_ready */
        ret = miphy365x_rdy(miphy_phy, miphy_dev);
        if (ret)
                return ret;

        /*
         * Enable macro1 to use rx_lspd & tx_lspd
         * Release Rx_Clock on first I-DLL phase on macro1
         * Assert deserializer reset
         * des_bit_lock_en is set
         * bit lock detection strength
         * Deassert deserializer reset
         */
        writeb_relaxed(0x00, miphy_phy->base + BOUNDARY1_REG);
        writeb_relaxed(0x00, miphy_phy->base + IDLL_TEST_REG);
        writeb_relaxed(RST_RX, miphy_phy->base + RESET_REG);
        val = miphy_phy->sata_tx_pol_inv ?
                (TX_POL | DES_BIT_LOCK_EN) : DES_BIT_LOCK_EN;
        writeb_relaxed(val, miphy_phy->base + CTRL_REG);

        val = BIT_LOCK_CNT_512 | BIT_LOCK_LEVEL;
        writeb_relaxed(val, miphy_phy->base + DES_BITLOCK_REG);
        writeb_relaxed(0x00, miphy_phy->base + RESET_REG);

        return 0;
}

static int miphy365x_init(struct phy *phy)
{
        struct miphy365x_phy *miphy_phy = phy_get_drvdata(phy);
        struct miphy365x_dev *miphy_dev = dev_get_drvdata(phy->dev.parent);
        int ret = 0;

        mutex_lock(&miphy_dev->miphy_mutex);

        ret = miphy365x_set_path(miphy_phy, miphy_dev);
        if (ret) {
                mutex_unlock(&miphy_dev->miphy_mutex);
                return ret;
        }

        /* Initialise Miphy for PCIe or SATA */
        if (miphy_phy->type == PHY_TYPE_PCIE)
                ret = miphy365x_init_pcie_port(miphy_phy, miphy_dev);
        else
                ret = miphy365x_init_sata_port(miphy_phy, miphy_dev);

        mutex_unlock(&miphy_dev->miphy_mutex);

        return ret;
}

static int miphy365x_get_addr(struct device *dev,
                struct miphy365x_phy *miphy_phy, int index)
{
        struct device_node *phynode = miphy_phy->phy->dev.of_node;
        const char *name;
        int type = miphy_phy->type;
        int ret;

        ret = of_property_read_string_index(phynode, "reg-names", index, &name);
        if (ret) {
                dev_err(dev, "no reg-names property not found\n");
                return ret;
        }

        if (!((!strncmp(name, "sata", 4) && type == PHY_TYPE_SATA) ||
              (!strncmp(name, "pcie", 4) && type == PHY_TYPE_PCIE)))
                return 0;

        miphy_phy->base = of_iomap(phynode, index);
        if (!miphy_phy->base) {
                dev_err(dev, "Failed to map %s\n", phynode->full_name);
                return -EINVAL;
        }

        return 0;
}

static struct phy *miphy365x_xlate(struct device *dev,
                                   struct of_phandle_args *args)
{
        struct miphy365x_dev *miphy_dev = dev_get_drvdata(dev);
        struct miphy365x_phy *miphy_phy = NULL;
        struct device_node *phynode = args->np;
        int ret, index;

        if (args->args_count != 1) {
                dev_err(dev, "Invalid number of cells in 'phy' property\n");
                return ERR_PTR(-EINVAL);
        }

        for (index = 0; index < miphy_dev->nphys; index++)
                if (phynode == miphy_dev->phys[index]->phy->dev.of_node) {
                        miphy_phy = miphy_dev->phys[index];
                        break;
                }

        if (!miphy_phy) {
                dev_err(dev, "Failed to find appropriate phy\n");
                return ERR_PTR(-EINVAL);
        }

        miphy_phy->type = args->args[0];

        if (!(miphy_phy->type == PHY_TYPE_SATA ||
              miphy_phy->type == PHY_TYPE_PCIE)) {
                dev_err(dev, "Unsupported device type: %d\n", miphy_phy->type);
                return ERR_PTR(-EINVAL);
        }

        /* Each port handles SATA and PCIE - third entry is always sysconf. */
        for (index = 0; index < 3; index++) {
                ret = miphy365x_get_addr(dev, miphy_phy, index);
                if (ret < 0)
                        return ERR_PTR(ret);
        }

        return miphy_phy->phy;
}

static const struct phy_ops miphy365x_ops = {
        .init           = miphy365x_init,
        .owner          = THIS_MODULE,
};

static int miphy365x_of_probe(struct device_node *phynode,
                              struct miphy365x_phy *miphy_phy)
{
        of_property_read_u32(phynode, "st,sata-gen", &miphy_phy->sata_gen);
        if (!miphy_phy->sata_gen)
                miphy_phy->sata_gen = SATA_GEN1;

        miphy_phy->pcie_tx_pol_inv =
                of_property_read_bool(phynode, "st,pcie-tx-pol-inv");

        miphy_phy->sata_tx_pol_inv =
                of_property_read_bool(phynode, "st,sata-tx-pol-inv");

        return 0;
}

static int miphy365x_probe(struct platform_device *pdev)
{
        struct device_node *child, *np = pdev->dev.of_node;
        struct miphy365x_dev *miphy_dev;
        struct phy_provider *provider;
        struct phy *phy;
        int ret, port = 0;

        miphy_dev = devm_kzalloc(&pdev->dev, sizeof(*miphy_dev), GFP_KERNEL);
        if (!miphy_dev)
                return -ENOMEM;

        miphy_dev->nphys = of_get_child_count(np);
        miphy_dev->phys = devm_kcalloc(&pdev->dev, miphy_dev->nphys,
                                       sizeof(*miphy_dev->phys), GFP_KERNEL);
        if (!miphy_dev->phys)
                return -ENOMEM;

        miphy_dev->regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
        if (IS_ERR(miphy_dev->regmap)) {
                dev_err(miphy_dev->dev, "No syscfg phandle specified\n");
                return PTR_ERR(miphy_dev->regmap);
        }

        miphy_dev->dev = &pdev->dev;

        dev_set_drvdata(&pdev->dev, miphy_dev);

        mutex_init(&miphy_dev->miphy_mutex);

        for_each_child_of_node(np, child) {
                struct miphy365x_phy *miphy_phy;

                miphy_phy = devm_kzalloc(&pdev->dev, sizeof(*miphy_phy),
                                         GFP_KERNEL);
                if (!miphy_phy) {
                        ret = -ENOMEM;
                        goto put_child;
                }

                miphy_dev->phys[port] = miphy_phy;

                phy = devm_phy_create(&pdev->dev, child, &miphy365x_ops);
                if (IS_ERR(phy)) {
                        dev_err(&pdev->dev, "failed to create PHY\n");
                        ret = PTR_ERR(phy);
                        goto put_child;
                }

                miphy_dev->phys[port]->phy = phy;

                ret = miphy365x_of_probe(child, miphy_phy);
                if (ret)
                        goto put_child;

                phy_set_drvdata(phy, miphy_dev->phys[port]);

                port++;
                /* sysconfig offsets are indexed from 1 */
                ret = of_property_read_u32_index(np, "st,syscfg", port,
                                        &miphy_phy->ctrlreg);
                if (ret) {
                        dev_err(&pdev->dev, "No sysconfig offset found\n");
                        goto put_child;
                }
        }

        provider = devm_of_phy_provider_register(&pdev->dev, miphy365x_xlate);
        return PTR_ERR_OR_ZERO(provider);
put_child:
        of_node_put(child);
        return ret;
}

static const struct of_device_id miphy365x_of_match[] = {
        { .compatible = "st,miphy365x-phy", },
        { },
};
MODULE_DEVICE_TABLE(of, miphy365x_of_match);

static struct platform_driver miphy365x_driver = {
        .probe  = miphy365x_probe,
        .driver = {
                .name   = "miphy365x-phy",
                .of_match_table = miphy365x_of_match,
        }
};
module_platform_driver(miphy365x_driver);

MODULE_AUTHOR("Alexandre Torgue <alexandre.torgue@st.com>");
MODULE_DESCRIPTION("STMicroelectronics miphy365x driver");
MODULE_LICENSE("GPL v2");