/*
 * Copyright (C) 2017 Samsung Electronics
 *
 * Authors:
 *    Tomasz Stanislawski <t.stanislaws@samsung.com>
 *    Maciej Purski <m.purski@samsung.com>
 *
 * Based on sii9234 driver created by:
 *    Adam Hampson <ahampson@sta.samsung.com>
 *    Erik Gilling <konkers@android.com>
 *    Shankar Bandal <shankar.b@samsung.com>
 *    Dharam Kumar <dharam.kr@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program
 *
 */
#include <drm/bridge/mhl.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#define CBUS_DEVCAP_OFFSET              0x80

#define SII9234_MHL_VERSION             0x11
#define SII9234_SCRATCHPAD_SIZE         0x10
#define SII9234_INT_STAT_SIZE           0x33

#define BIT_TMDS_CCTRL_TMDS_OE          BIT(4)
#define MHL_HPD_OUT_OVR_EN              BIT(4)
#define MHL_HPD_OUT_OVR_VAL             BIT(5)
#define MHL_INIT_TIMEOUT                0x0C

/* MHL Tx registers and bits */
#define MHL_TX_SRST                     0x05
#define MHL_TX_SYSSTAT_REG              0x09
#define MHL_TX_INTR1_REG                0x71
#define MHL_TX_INTR4_REG                0x74
#define MHL_TX_INTR1_ENABLE_REG         0x75
#define MHL_TX_INTR4_ENABLE_REG         0x78
#define MHL_TX_INT_CTRL_REG             0x79
#define MHL_TX_TMDS_CCTRL               0x80
#define MHL_TX_DISC_CTRL1_REG           0x90
#define MHL_TX_DISC_CTRL2_REG           0x91
#define MHL_TX_DISC_CTRL3_REG           0x92
#define MHL_TX_DISC_CTRL4_REG           0x93
#define MHL_TX_DISC_CTRL5_REG           0x94
#define MHL_TX_DISC_CTRL6_REG           0x95
#define MHL_TX_DISC_CTRL7_REG           0x96
#define MHL_TX_DISC_CTRL8_REG           0x97
#define MHL_TX_STAT2_REG                0x99
#define MHL_TX_MHLTX_CTL1_REG           0xA0
#define MHL_TX_MHLTX_CTL2_REG           0xA1
#define MHL_TX_MHLTX_CTL4_REG           0xA3
#define MHL_TX_MHLTX_CTL6_REG           0xA5
#define MHL_TX_MHLTX_CTL7_REG           0xA6

#define RSEN_STATUS                     BIT(2)
#define HPD_CHANGE_INT                  BIT(6)
#define RSEN_CHANGE_INT                 BIT(5)
#define RGND_READY_INT                  BIT(6)
#define VBUS_LOW_INT                    BIT(5)
#define CBUS_LKOUT_INT                  BIT(4)
#define MHL_DISC_FAIL_INT               BIT(3)
#define MHL_EST_INT                     BIT(2)
#define HPD_CHANGE_INT_MASK             BIT(6)
#define RSEN_CHANGE_INT_MASK            BIT(5)

#define RGND_READY_MASK                 BIT(6)
#define CBUS_LKOUT_MASK                 BIT(4)
#define MHL_DISC_FAIL_MASK              BIT(3)
#define MHL_EST_MASK                    BIT(2)

#define SKIP_GND                        BIT(6)

#define ATT_THRESH_SHIFT                0x04
#define ATT_THRESH_MASK                 (0x03 << ATT_THRESH_SHIFT)
#define USB_D_OEN                       BIT(3)
#define DEGLITCH_TIME_MASK              0x07
#define DEGLITCH_TIME_2MS               0
#define DEGLITCH_TIME_4MS               1
#define DEGLITCH_TIME_8MS               2
#define DEGLITCH_TIME_16MS              3
#define DEGLITCH_TIME_40MS              4
#define DEGLITCH_TIME_50MS              5
#define DEGLITCH_TIME_60MS              6
#define DEGLITCH_TIME_128MS             7

#define USB_D_OVR                       BIT(7)
#define USB_ID_OVR                      BIT(6)
#define DVRFLT_SEL                      BIT(5)
#define BLOCK_RGND_INT                  BIT(4)
#define SKIP_DEG                        BIT(3)
#define CI2CA_POL                       BIT(2)
#define CI2CA_WKUP                      BIT(1)
#define SINGLE_ATT                      BIT(0)

#define USB_D_ODN                       BIT(5)
#define VBUS_CHECK                      BIT(2)
#define RGND_INTP_MASK                  0x03
#define RGND_INTP_OPEN                  0
#define RGND_INTP_2K                    1
#define RGND_INTP_1K                    2
#define RGND_INTP_SHORT                 3

/* HDMI registers */
#define HDMI_RX_TMDS0_CCTRL1_REG        0x10
#define HDMI_RX_TMDS_CLK_EN_REG         0x11
#define HDMI_RX_TMDS_CH_EN_REG          0x12
#define HDMI_RX_PLL_CALREFSEL_REG       0x17
#define HDMI_RX_PLL_VCOCAL_REG          0x1A
#define HDMI_RX_EQ_DATA0_REG            0x22
#define HDMI_RX_EQ_DATA1_REG            0x23
#define HDMI_RX_EQ_DATA2_REG            0x24
#define HDMI_RX_EQ_DATA3_REG            0x25
#define HDMI_RX_EQ_DATA4_REG            0x26
#define HDMI_RX_TMDS_ZONE_CTRL_REG      0x4C
#define HDMI_RX_TMDS_MODE_CTRL_REG      0x4D

/* CBUS registers */
#define CBUS_INT_STATUS_1_REG           0x08
#define CBUS_INTR1_ENABLE_REG           0x09
#define CBUS_MSC_REQ_ABORT_REASON_REG   0x0D
#define CBUS_INT_STATUS_2_REG           0x1E
#define CBUS_INTR2_ENABLE_REG           0x1F
#define CBUS_LINK_CONTROL_2_REG         0x31
#define CBUS_MHL_STATUS_REG_0           0xB0
#define CBUS_MHL_STATUS_REG_1           0xB1

#define BIT_CBUS_RESET                  BIT(3)
#define SET_HPD_DOWNSTREAM              BIT(6)

/* TPI registers */
#define TPI_DPD_REG                     0x3D

/* Timeouts in msec */
#define T_SRC_VBUS_CBUS_TO_STABLE       200
#define T_SRC_CBUS_FLOAT                100
#define T_SRC_CBUS_DEGLITCH             2
#define T_SRC_RXSENSE_DEGLITCH          110

#define MHL1_MAX_CLK                    75000 /* in kHz */

#define I2C_TPI_ADDR                    0x3D
#define I2C_HDMI_ADDR                   0x49
#define I2C_CBUS_ADDR                   0x64

enum sii9234_state {
        ST_OFF,
        ST_D3,
        ST_RGND_INIT,
        ST_RGND_1K,
        ST_RSEN_HIGH,
        ST_MHL_ESTABLISHED,
        ST_FAILURE_DISCOVERY,
        ST_FAILURE,
};

struct sii9234 {
        struct i2c_client *client[4];
        struct drm_bridge bridge;
        struct device *dev;
        struct gpio_desc *gpio_reset;
        int i2c_error;
        struct regulator_bulk_data supplies[4];

        struct mutex lock; /* Protects fields below and device registers */
        enum sii9234_state state;
};

enum sii9234_client_id {
        I2C_MHL,
        I2C_TPI,
        I2C_HDMI,
        I2C_CBUS,
};

static const char * const sii9234_client_name[] = {
        [I2C_MHL] = "MHL",
        [I2C_TPI] = "TPI",
        [I2C_HDMI] = "HDMI",
        [I2C_CBUS] = "CBUS",
};

static int sii9234_writeb(struct sii9234 *ctx, int id, int offset,
                          int value)
{
        int ret;
        struct i2c_client *client = ctx->client[id];

        if (ctx->i2c_error)
                return ctx->i2c_error;

        ret = i2c_smbus_write_byte_data(client, offset, value);
        if (ret < 0)
                dev_err(ctx->dev, "writeb: %4s[0x%02x] <- 0x%02x\n",
                        sii9234_client_name[id], offset, value);
        ctx->i2c_error = ret;

        return ret;
}

static int sii9234_writebm(struct sii9234 *ctx, int id, int offset,
                           int value, int mask)
{
        int ret;
        struct i2c_client *client = ctx->client[id];

        if (ctx->i2c_error)
                return ctx->i2c_error;

        ret = i2c_smbus_write_byte(client, offset);
        if (ret < 0) {
                dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
                        sii9234_client_name[id], offset, value);
                ctx->i2c_error = ret;
                return ret;
        }

        ret = i2c_smbus_read_byte(client);
        if (ret < 0) {
                dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
                        sii9234_client_name[id], offset, value);
                ctx->i2c_error = ret;
                return ret;
        }

        value = (value & mask) | (ret & ~mask);

        ret = i2c_smbus_write_byte_data(client, offset, value);
        if (ret < 0) {
                dev_err(ctx->dev, "writebm: %4s[0x%02x] <- 0x%02x\n",
                        sii9234_client_name[id], offset, value);
                ctx->i2c_error = ret;
        }

        return ret;
}

static int sii9234_readb(struct sii9234 *ctx, int id, int offset)
{
        int ret;
        struct i2c_client *client = ctx->client[id];

        if (ctx->i2c_error)
                return ctx->i2c_error;

        ret = i2c_smbus_write_byte(client, offset);
        if (ret < 0) {
                dev_err(ctx->dev, "readb: %4s[0x%02x]\n",
                        sii9234_client_name[id], offset);
                ctx->i2c_error = ret;
                return ret;
        }

        ret = i2c_smbus_read_byte(client);
        if (ret < 0) {
                dev_err(ctx->dev, "readb: %4s[0x%02x]\n",
                        sii9234_client_name[id], offset);
                ctx->i2c_error = ret;
        }

        return ret;
}

static int sii9234_clear_error(struct sii9234 *ctx)
{
        int ret = ctx->i2c_error;

        ctx->i2c_error = 0;

        return ret;
}

#define mhl_tx_writeb(sii9234, offset, value) \
        sii9234_writeb(sii9234, I2C_MHL, offset, value)
#define mhl_tx_writebm(sii9234, offset, value, mask) \
        sii9234_writebm(sii9234, I2C_MHL, offset, value, mask)
#define mhl_tx_readb(sii9234, offset) \
        sii9234_readb(sii9234, I2C_MHL, offset)
#define cbus_writeb(sii9234, offset, value) \
        sii9234_writeb(sii9234, I2C_CBUS, offset, value)
#define cbus_writebm(sii9234, offset, value, mask) \
        sii9234_writebm(sii9234, I2C_CBUS, offset, value, mask)
#define cbus_readb(sii9234, offset) \
        sii9234_readb(sii9234, I2C_CBUS, offset)
#define hdmi_writeb(sii9234, offset, value) \
        sii9234_writeb(sii9234, I2C_HDMI, offset, value)
#define hdmi_writebm(sii9234, offset, value, mask) \
        sii9234_writebm(sii9234, I2C_HDMI, offset, value, mask)
#define hdmi_readb(sii9234, offset) \
        sii9234_readb(sii9234, I2C_HDMI, offset)
#define tpi_writeb(sii9234, offset, value) \
        sii9234_writeb(sii9234, I2C_TPI, offset, value)
#define tpi_writebm(sii9234, offset, value, mask) \
        sii9234_writebm(sii9234, I2C_TPI, offset, value, mask)
#define tpi_readb(sii9234, offset) \
        sii9234_readb(sii9234, I2C_TPI, offset)

static u8 sii9234_tmds_control(struct sii9234 *ctx, bool enable)
{
        mhl_tx_writebm(ctx, MHL_TX_TMDS_CCTRL, enable ? ~0 : 0,
                       BIT_TMDS_CCTRL_TMDS_OE);
        mhl_tx_writebm(ctx, MHL_TX_INT_CTRL_REG, enable ? ~0 : 0,
                       MHL_HPD_OUT_OVR_EN | MHL_HPD_OUT_OVR_VAL);
        return sii9234_clear_error(ctx);
}

static int sii9234_cbus_reset(struct sii9234 *ctx)
{
        int i;

        mhl_tx_writebm(ctx, MHL_TX_SRST, ~0, BIT_CBUS_RESET);
        msleep(T_SRC_CBUS_DEGLITCH);
        mhl_tx_writebm(ctx, MHL_TX_SRST, 0, BIT_CBUS_RESET);

        for (i = 0; i < 4; i++) {
                /*
                 * Enable WRITE_STAT interrupt for writes to all
                 * 4 MSC Status registers.
                 */
                cbus_writeb(ctx, 0xE0 + i, 0xF2);
                /*
                 * Enable SET_INT interrupt for writes to all
                 * 4 MSC Interrupt registers.
                 */
                cbus_writeb(ctx, 0xF0 + i, 0xF2);
        }

        return sii9234_clear_error(ctx);
}

/* Require to chek mhl imformation of samsung in cbus_init_register */
static int sii9234_cbus_init(struct sii9234 *ctx)
{
        cbus_writeb(ctx, 0x07, 0xF2);
        cbus_writeb(ctx, 0x40, 0x03);
        cbus_writeb(ctx, 0x42, 0x06);
        cbus_writeb(ctx, 0x36, 0x0C);
        cbus_writeb(ctx, 0x3D, 0xFD);
        cbus_writeb(ctx, 0x1C, 0x01);
        cbus_writeb(ctx, 0x1D, 0x0F);
        cbus_writeb(ctx, 0x44, 0x02);
        /* Setup our devcap */
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_DEV_STATE, 0x00);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_MHL_VERSION,
                    SII9234_MHL_VERSION);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_CAT,
                    MHL_DCAP_CAT_SOURCE);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_ADOPTER_ID_H, 0x01);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_ADOPTER_ID_L, 0x41);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_VID_LINK_MODE,
                    MHL_DCAP_VID_LINK_RGB444 | MHL_DCAP_VID_LINK_YCBCR444);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_VIDEO_TYPE,
                    MHL_DCAP_VT_GRAPHICS);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_LOG_DEV_MAP,
                    MHL_DCAP_LD_GUI);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_BANDWIDTH, 0x0F);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_FEATURE_FLAG,
                    MHL_DCAP_FEATURE_RCP_SUPPORT | MHL_DCAP_FEATURE_RAP_SUPPORT
                        | MHL_DCAP_FEATURE_SP_SUPPORT);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_DEVICE_ID_H, 0x0);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_DEVICE_ID_L, 0x0);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_SCRATCHPAD_SIZE,
                    SII9234_SCRATCHPAD_SIZE);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_INT_STAT_SIZE,
                    SII9234_INT_STAT_SIZE);
        cbus_writeb(ctx, CBUS_DEVCAP_OFFSET + MHL_DCAP_RESERVED, 0);
        cbus_writebm(ctx, 0x31, 0x0C, 0x0C);
        cbus_writeb(ctx, 0x30, 0x01);
        cbus_writebm(ctx, 0x3C, 0x30, 0x38);
        cbus_writebm(ctx, 0x22, 0x0D, 0x0F);
        cbus_writebm(ctx, 0x2E, 0x15, 0x15);
        cbus_writeb(ctx, CBUS_INTR1_ENABLE_REG, 0);
        cbus_writeb(ctx, CBUS_INTR2_ENABLE_REG, 0);

        return sii9234_clear_error(ctx);
}

static void force_usb_id_switch_open(struct sii9234 *ctx)
{
        /* Disable CBUS discovery */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL1_REG, 0, 0x01);
        /* Force USB ID switch to open */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL6_REG, ~0, USB_ID_OVR);
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL3_REG, ~0, 0x86);
        /* Force upstream HPD to 0 when not in MHL mode. */
        mhl_tx_writebm(ctx, MHL_TX_INT_CTRL_REG, 0, 0x30);
}

static void release_usb_id_switch_open(struct sii9234 *ctx)
{
        msleep(T_SRC_CBUS_FLOAT);
        /* Clear USB ID switch to open */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL6_REG, 0, USB_ID_OVR);
        /* Enable CBUS discovery */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL1_REG, ~0, 0x01);
}

static int sii9234_power_init(struct sii9234 *ctx)
{
        /* Force the SiI9234 into the D0 state. */
        tpi_writeb(ctx, TPI_DPD_REG, 0x3F);
        /* Enable TxPLL Clock */
        hdmi_writeb(ctx, HDMI_RX_TMDS_CLK_EN_REG, 0x01);
        /* Enable Tx Clock Path & Equalizer */
        hdmi_writeb(ctx, HDMI_RX_TMDS_CH_EN_REG, 0x15);
        /* Power Up TMDS */
        mhl_tx_writeb(ctx, 0x08, 0x35);
        return sii9234_clear_error(ctx);
}

static int sii9234_hdmi_init(struct sii9234 *ctx)
{
        hdmi_writeb(ctx, HDMI_RX_TMDS0_CCTRL1_REG, 0xC1);
        hdmi_writeb(ctx, HDMI_RX_PLL_CALREFSEL_REG, 0x03);
        hdmi_writeb(ctx, HDMI_RX_PLL_VCOCAL_REG, 0x20);
        hdmi_writeb(ctx, HDMI_RX_EQ_DATA0_REG, 0x8A);
        hdmi_writeb(ctx, HDMI_RX_EQ_DATA1_REG, 0x6A);
        hdmi_writeb(ctx, HDMI_RX_EQ_DATA2_REG, 0xAA);
        hdmi_writeb(ctx, HDMI_RX_EQ_DATA3_REG, 0xCA);
        hdmi_writeb(ctx, HDMI_RX_EQ_DATA4_REG, 0xEA);
        hdmi_writeb(ctx, HDMI_RX_TMDS_ZONE_CTRL_REG, 0xA0);
        hdmi_writeb(ctx, HDMI_RX_TMDS_MODE_CTRL_REG, 0x00);
        mhl_tx_writeb(ctx, MHL_TX_TMDS_CCTRL, 0x34);
        hdmi_writeb(ctx, 0x45, 0x44);
        hdmi_writeb(ctx, 0x31, 0x0A);
        hdmi_writeb(ctx, HDMI_RX_TMDS0_CCTRL1_REG, 0xC1);

        return sii9234_clear_error(ctx);
}

static int sii9234_mhl_tx_ctl_int(struct sii9234 *ctx)
{
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL1_REG, 0xD0);
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL2_REG, 0xFC);
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL4_REG, 0xEB);
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL7_REG, 0x0C);

        return sii9234_clear_error(ctx);
}

static int sii9234_reset(struct sii9234 *ctx)
{
        int ret;

        sii9234_clear_error(ctx);

        ret = sii9234_power_init(ctx);
        if (ret < 0)
                return ret;
        ret = sii9234_cbus_reset(ctx);
        if (ret < 0)
                return ret;
        ret = sii9234_hdmi_init(ctx);
        if (ret < 0)
                return ret;
        ret = sii9234_mhl_tx_ctl_int(ctx);
        if (ret < 0)
                return ret;

        /* Enable HDCP Compliance safety */
        mhl_tx_writeb(ctx, 0x2B, 0x01);
        /* CBUS discovery cycle time for each drive and float = 150us */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL1_REG, 0x04, 0x06);
        /* Clear bit 6 (reg_skip_rgnd) */
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL2_REG, (1 << 7) /* Reserved */
                      | 2 << ATT_THRESH_SHIFT | DEGLITCH_TIME_50MS);
        /*
         * Changed from 66 to 65 for 94[1:0] = 01 = 5k reg_cbusmhl_pup_sel
         * 1.8V CBUS VTH & GND threshold
         * to meet CTS 3.3.7.2 spec
         */
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL5_REG, 0x77);
        cbus_writebm(ctx, CBUS_LINK_CONTROL_2_REG, ~0, MHL_INIT_TIMEOUT);
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL6_REG, 0xA0);
        /* RGND & single discovery attempt (RGND blocking) */
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL6_REG, BLOCK_RGND_INT |
                      DVRFLT_SEL | SINGLE_ATT);
        /* Use VBUS path of discovery state machine */
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL8_REG, 0);
        /* 0x92[3] sets the CBUS / ID switch */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL6_REG, ~0, USB_ID_OVR);
        /*
         * To allow RGND engine to operate correctly.
         * When moving the chip from D2 to D0 (power up, init regs)
         * the values should be
         * 94[1:0] = 01  reg_cbusmhl_pup_sel[1:0] should be set for 5k
         * 93[7:6] = 10  reg_cbusdisc_pup_sel[1:0] should be
         * set for 10k (default)
         * 93[5:4] = 00  reg_cbusidle_pup_sel[1:0] = open (default)
         */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL3_REG, ~0, 0x86);
        /*
         * Change from CC to 8C to match 5K
         * to meet CTS 3.3.72 spec
         */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL4_REG, ~0, 0x8C);
        /* Configure the interrupt as active high */
        mhl_tx_writebm(ctx, MHL_TX_INT_CTRL_REG, 0, 0x06);

        msleep(25);

        /* Release usb_id switch */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL6_REG, 0,  USB_ID_OVR);
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL1_REG, 0x27);

        ret = sii9234_clear_error(ctx);
        if (ret < 0)
                return ret;
        ret = sii9234_cbus_init(ctx);
        if (ret < 0)
                return ret;

        /* Enable Auto soft reset on SCDT = 0 */
        mhl_tx_writeb(ctx, 0x05, 0x04);
        /* HDMI Transcode mode enable */
        mhl_tx_writeb(ctx, 0x0D, 0x1C);
        mhl_tx_writeb(ctx, MHL_TX_INTR4_ENABLE_REG,
                      RGND_READY_MASK | CBUS_LKOUT_MASK
                        | MHL_DISC_FAIL_MASK | MHL_EST_MASK);
        mhl_tx_writeb(ctx, MHL_TX_INTR1_ENABLE_REG, 0x60);

        /* This point is very important before measure RGND impedance */
        force_usb_id_switch_open(ctx);
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL4_REG, 0, 0xF0);
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL5_REG, 0, 0x03);
        release_usb_id_switch_open(ctx);

        /* Force upstream HPD to 0 when not in MHL mode */
        mhl_tx_writebm(ctx, MHL_TX_INT_CTRL_REG, 0, 1 << 5);
        mhl_tx_writebm(ctx, MHL_TX_INT_CTRL_REG, ~0, 1 << 4);

        return sii9234_clear_error(ctx);
}

static int sii9234_goto_d3(struct sii9234 *ctx)
{
        int ret;

        dev_dbg(ctx->dev, "sii9234: detection started d3\n");

        ret = sii9234_reset(ctx);
        if (ret < 0)
                goto exit;

        hdmi_writeb(ctx, 0x01, 0x03);
        tpi_writebm(ctx, TPI_DPD_REG, 0, 1);
        /* I2C above is expected to fail because power goes down */
        sii9234_clear_error(ctx);

        ctx->state = ST_D3;

        return 0;
 exit:
        dev_err(ctx->dev, "%s failed\n", __func__);
        return -1;
}

static int sii9234_hw_on(struct sii9234 *ctx)
{
        return regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
}

static void sii9234_hw_off(struct sii9234 *ctx)
{
        gpiod_set_value(ctx->gpio_reset, 1);
        msleep(20);
        regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
}

static void sii9234_hw_reset(struct sii9234 *ctx)
{
        gpiod_set_value(ctx->gpio_reset, 1);
        msleep(20);
        gpiod_set_value(ctx->gpio_reset, 0);
}

static void sii9234_cable_in(struct sii9234 *ctx)
{
        int ret;

        mutex_lock(&ctx->lock);
        if (ctx->state != ST_OFF)
                goto unlock;
        ret = sii9234_hw_on(ctx);
        if (ret < 0)
                goto unlock;

        sii9234_hw_reset(ctx);
        sii9234_goto_d3(ctx);
        /* To avoid irq storm, when hw is in meta state */
        enable_irq(to_i2c_client(ctx->dev)->irq);

unlock:
        mutex_unlock(&ctx->lock);
}

static void sii9234_cable_out(struct sii9234 *ctx)
{
        mutex_lock(&ctx->lock);

        if (ctx->state == ST_OFF)
                goto unlock;

        disable_irq(to_i2c_client(ctx->dev)->irq);
        tpi_writeb(ctx, TPI_DPD_REG, 0);
        /* Turn on&off hpd festure for only QCT HDMI */
        sii9234_hw_off(ctx);

        ctx->state = ST_OFF;

unlock:
        mutex_unlock(&ctx->lock);
}

static enum sii9234_state sii9234_rgnd_ready_irq(struct sii9234 *ctx)
{
        int value;

        if (ctx->state == ST_D3) {
                int ret;

                dev_dbg(ctx->dev, "RGND_READY_INT\n");
                sii9234_hw_reset(ctx);

                ret = sii9234_reset(ctx);
                if (ret < 0) {
                        dev_err(ctx->dev, "sii9234_reset() failed\n");
                        return ST_FAILURE;
                }

                return ST_RGND_INIT;
        }

        /* Got interrupt in inappropriate state */
        if (ctx->state != ST_RGND_INIT)
                return ST_FAILURE;

        value = mhl_tx_readb(ctx, MHL_TX_STAT2_REG);
        if (sii9234_clear_error(ctx))
                return ST_FAILURE;

        if ((value & RGND_INTP_MASK) != RGND_INTP_1K) {
                dev_warn(ctx->dev, "RGND is not 1k\n");
                return ST_RGND_INIT;
        }
        dev_dbg(ctx->dev, "RGND 1K!!\n");
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL4_REG, ~0, 0x8C);
        mhl_tx_writeb(ctx, MHL_TX_DISC_CTRL5_REG, 0x77);
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL6_REG, ~0, 0x05);
        if (sii9234_clear_error(ctx))
                return ST_FAILURE;

        msleep(T_SRC_VBUS_CBUS_TO_STABLE);
        return ST_RGND_1K;
}

static enum sii9234_state sii9234_mhl_established(struct sii9234 *ctx)
{
        dev_dbg(ctx->dev, "mhl est interrupt\n");

        /* Discovery override */
        mhl_tx_writeb(ctx, MHL_TX_MHLTX_CTL1_REG, 0x10);
        /* Increase DDC translation layer timer (byte mode) */
        cbus_writeb(ctx, 0x07, 0x32);
        cbus_writebm(ctx, 0x44, ~0, 1 << 1);
        /* Keep the discovery enabled. Need RGND interrupt */
        mhl_tx_writebm(ctx, MHL_TX_DISC_CTRL1_REG, ~0, 1);
        mhl_tx_writeb(ctx, MHL_TX_INTR1_ENABLE_REG,
                      RSEN_CHANGE_INT_MASK | HPD_CHANGE_INT_MASK);

        if (sii9234_clear_error(ctx))
                return ST_FAILURE;

        return ST_MHL_ESTABLISHED;
}

static enum sii9234_state sii9234_hpd_change(struct sii9234 *ctx)
{
        int value;

        value = cbus_readb(ctx, CBUS_MSC_REQ_ABORT_REASON_REG);
        if (sii9234_clear_error(ctx))
                return ST_FAILURE;

        if (value & SET_HPD_DOWNSTREAM) {
                /* Downstream HPD High, Enable TMDS */
                sii9234_tmds_control(ctx, true);
        } else {
                /* Downstream HPD Low, Disable TMDS */
                sii9234_tmds_control(ctx, false);
        }

        return ctx->state;
}

static enum sii9234_state sii9234_rsen_change(struct sii9234 *ctx)
{
        int value;

        /* Work_around code to handle wrong interrupt */
        if (ctx->state != ST_RGND_1K) {
                dev_err(ctx->dev, "RSEN_HIGH without RGND_1K\n");
                return ST_FAILURE;
        }
        value = mhl_tx_readb(ctx, MHL_TX_SYSSTAT_REG);
        if (value < 0)
                return ST_FAILURE;

        if (value & RSEN_STATUS) {
                dev_dbg(ctx->dev, "MHL cable connected.. RSEN High\n");
                return ST_RSEN_HIGH;
        }
        dev_dbg(ctx->dev, "RSEN lost\n");
        /*
         * Once RSEN loss is confirmed,we need to check
         * based on cable status and chip power status,whether
         * it is SINK Loss(HDMI cable not connected, TV Off)
         * or MHL cable disconnection
         * TODO: Define the below mhl_disconnection()
         */
        msleep(T_SRC_RXSENSE_DEGLITCH);
        value = mhl_tx_readb(ctx, MHL_TX_SYSSTAT_REG);
        if (value < 0)
                return ST_FAILURE;
        dev_dbg(ctx->dev, "sys_stat: %x\n", value);

        if (value & RSEN_STATUS) {
                dev_dbg(ctx->dev, "RSEN recovery\n");
                return ST_RSEN_HIGH;
        }
        dev_dbg(ctx->dev, "RSEN Really LOW\n");
        /* To meet CTS 3.3.22.2 spec */
        sii9234_tmds_control(ctx, false);
        force_usb_id_switch_open(ctx);
        release_usb_id_switch_open(ctx);

        return ST_FAILURE;
}

static irqreturn_t sii9234_irq_thread(int irq, void *data)
{
        struct sii9234 *ctx = data;
        int intr1, intr4;
        int intr1_en, intr4_en;
        int cbus_intr1, cbus_intr2;

        dev_dbg(ctx->dev, "%s\n", __func__);

        mutex_lock(&ctx->lock);

        intr1 = mhl_tx_readb(ctx, MHL_TX_INTR1_REG);
        intr4 = mhl_tx_readb(ctx, MHL_TX_INTR4_REG);
        intr1_en = mhl_tx_readb(ctx, MHL_TX_INTR1_ENABLE_REG);
        intr4_en = mhl_tx_readb(ctx, MHL_TX_INTR4_ENABLE_REG);
        cbus_intr1 = cbus_readb(ctx, CBUS_INT_STATUS_1_REG);
        cbus_intr2 = cbus_readb(ctx, CBUS_INT_STATUS_2_REG);

        if (sii9234_clear_error(ctx))
                goto done;

        dev_dbg(ctx->dev, "irq %02x/%02x %02x/%02x %02x/%02x\n",
                intr1, intr1_en, intr4, intr4_en, cbus_intr1, cbus_intr2);

        if (intr4 & RGND_READY_INT)
                ctx->state = sii9234_rgnd_ready_irq(ctx);
        if (intr1 & RSEN_CHANGE_INT)
                ctx->state = sii9234_rsen_change(ctx);
        if (intr4 & MHL_EST_INT)
                ctx->state = sii9234_mhl_established(ctx);
        if (intr1 & HPD_CHANGE_INT)
                ctx->state = sii9234_hpd_change(ctx);
        if (intr4 & CBUS_LKOUT_INT)
                ctx->state = ST_FAILURE;
        if (intr4 & MHL_DISC_FAIL_INT)
                ctx->state = ST_FAILURE_DISCOVERY;

 done:
        /* Clean interrupt status and pending flags */
        mhl_tx_writeb(ctx, MHL_TX_INTR1_REG, intr1);
        mhl_tx_writeb(ctx, MHL_TX_INTR4_REG, intr4);
        cbus_writeb(ctx, CBUS_MHL_STATUS_REG_0, 0xFF);
        cbus_writeb(ctx, CBUS_MHL_STATUS_REG_1, 0xFF);
        cbus_writeb(ctx, CBUS_INT_STATUS_1_REG, cbus_intr1);
        cbus_writeb(ctx, CBUS_INT_STATUS_2_REG, cbus_intr2);

        sii9234_clear_error(ctx);

        if (ctx->state == ST_FAILURE) {
                dev_dbg(ctx->dev, "try to reset after failure\n");
                sii9234_hw_reset(ctx);
                sii9234_goto_d3(ctx);
        }

        if (ctx->state == ST_FAILURE_DISCOVERY) {
                dev_err(ctx->dev, "discovery failed, no power for MHL?\n");
                tpi_writebm(ctx, TPI_DPD_REG, 0, 1);
                ctx->state = ST_D3;
        }

        mutex_unlock(&ctx->lock);

        return IRQ_HANDLED;
}

static int sii9234_init_resources(struct sii9234 *ctx,
                                  struct i2c_client *client)
{
        struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
        int ret;

        if (!ctx->dev->of_node) {
                dev_err(ctx->dev, "not DT device\n");
                return -ENODEV;
        }

        ctx->gpio_reset = devm_gpiod_get(ctx->dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(ctx->gpio_reset)) {
                dev_err(ctx->dev, "failed to get reset gpio from DT\n");
                return PTR_ERR(ctx->gpio_reset);
        }

        ctx->supplies[0].supply = "avcc12";
        ctx->supplies[1].supply = "avcc33";
        ctx->supplies[2].supply = "iovcc18";
        ctx->supplies[3].supply = "cvcc12";
        ret = devm_regulator_bulk_get(ctx->dev, 4, ctx->supplies);
        if (ret) {
                dev_err(ctx->dev, "regulator_bulk failed\n");
                return ret;
        }

        ctx->client[I2C_MHL] = client;

        ctx->client[I2C_TPI] = i2c_new_dummy(adapter, I2C_TPI_ADDR);
        if (!ctx->client[I2C_TPI]) {
                dev_err(ctx->dev, "failed to create TPI client\n");
                return -ENODEV;
        }

        ctx->client[I2C_HDMI] = i2c_new_dummy(adapter, I2C_HDMI_ADDR);
        if (!ctx->client[I2C_HDMI]) {
                dev_err(ctx->dev, "failed to create HDMI RX client\n");
                goto fail_tpi;
        }

        ctx->client[I2C_CBUS] = i2c_new_dummy(adapter, I2C_CBUS_ADDR);
        if (!ctx->client[I2C_CBUS]) {
                dev_err(ctx->dev, "failed to create CBUS client\n");
                goto fail_hdmi;
        }

        return 0;

fail_hdmi:
        i2c_unregister_device(ctx->client[I2C_HDMI]);
fail_tpi:
        i2c_unregister_device(ctx->client[I2C_TPI]);

        return -ENODEV;
}

static void sii9234_deinit_resources(struct sii9234 *ctx)
{
        i2c_unregister_device(ctx->client[I2C_CBUS]);
        i2c_unregister_device(ctx->client[I2C_HDMI]);
        i2c_unregister_device(ctx->client[I2C_TPI]);
}

static inline struct sii9234 *bridge_to_sii9234(struct drm_bridge *bridge)
{
        return container_of(bridge, struct sii9234, bridge);
}

static enum drm_mode_status sii9234_mode_valid(struct drm_bridge *bridge,
                                         const struct drm_display_mode *mode)
{
        if (mode->clock > MHL1_MAX_CLK)
                return MODE_CLOCK_HIGH;

        return MODE_OK;
}

static const struct drm_bridge_funcs sii9234_bridge_funcs = {
        .mode_valid = sii9234_mode_valid,
};

static int sii9234_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
        struct sii9234 *ctx;
        struct device *dev = &client->dev;
        int ret;

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

        ctx->dev = dev;
        mutex_init(&ctx->lock);

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(dev, "I2C adapter lacks SMBUS feature\n");
                return -EIO;
        }

        if (!client->irq) {
                dev_err(dev, "no irq provided\n");
                return -EINVAL;
        }

        irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
        ret = devm_request_threaded_irq(dev, client->irq, NULL,
                                        sii9234_irq_thread,
                                        IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
                                        "sii9234", ctx);
        if (ret < 0) {
                dev_err(dev, "failed to install IRQ handler\n");
                return ret;
        }

        ret = sii9234_init_resources(ctx, client);
        if (ret < 0)
                return ret;

        i2c_set_clientdata(client, ctx);

        ctx->bridge.funcs = &sii9234_bridge_funcs;
        ctx->bridge.of_node = dev->of_node;
        drm_bridge_add(&ctx->bridge);

        sii9234_cable_in(ctx);

        return 0;
}

static int sii9234_remove(struct i2c_client *client)
{
        struct sii9234 *ctx = i2c_get_clientdata(client);

        sii9234_cable_out(ctx);
        drm_bridge_remove(&ctx->bridge);
        sii9234_deinit_resources(ctx);

        return 0;
}

static const struct of_device_id sii9234_dt_match[] = {
        { .compatible = "sil,sii9234" },
        { },
};
MODULE_DEVICE_TABLE(of, sii9234_dt_match);

static const struct i2c_device_id sii9234_id[] = {
        { "SII9234", 0 },
        { },
};
MODULE_DEVICE_TABLE(i2c, sii9234_id);

static struct i2c_driver sii9234_driver = {
        .driver = {
                .name   = "sii9234",
                .of_match_table = sii9234_dt_match,
        },
        .probe = sii9234_probe,
        .remove = sii9234_remove,
        .id_table = sii9234_id,
};

module_i2c_driver(sii9234_driver);
MODULE_LICENSE("GPL");