// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * tc358767 eDP bridge driver
 *
 * Copyright (C) 2016 CogentEmbedded Inc
 * Author: Andrey Gusakov <andrey.gusakov@cogentembedded.com>
 *
 * Copyright (C) 2016 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
 *
 * Copyright (C) 2016 Zodiac Inflight Innovations
 *
 * Initially based on: drivers/gpu/drm/i2c/tda998x_drv.c
 *
 * Copyright (C) 2012 Texas Instruments
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_dp_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

/* Registers */

/* Display Parallel Interface */
#define DPIPXLFMT               0x0440
#define VS_POL_ACTIVE_LOW               (1 << 10)
#define HS_POL_ACTIVE_LOW               (1 << 9)
#define DE_POL_ACTIVE_HIGH              (0 << 8)
#define SUB_CFG_TYPE_CONFIG1            (0 << 2) /* LSB aligned */
#define SUB_CFG_TYPE_CONFIG2            (1 << 2) /* Loosely Packed */
#define SUB_CFG_TYPE_CONFIG3            (2 << 2) /* LSB aligned 8-bit */
#define DPI_BPP_RGB888                  (0 << 0)
#define DPI_BPP_RGB666                  (1 << 0)
#define DPI_BPP_RGB565                  (2 << 0)

/* Video Path */
#define VPCTRL0                 0x0450
#define VSDELAY                 GENMASK(31, 20)
#define OPXLFMT_RGB666                  (0 << 8)
#define OPXLFMT_RGB888                  (1 << 8)
#define FRMSYNC_DISABLED                (0 << 4) /* Video Timing Gen Disabled */
#define FRMSYNC_ENABLED                 (1 << 4) /* Video Timing Gen Enabled */
#define MSF_DISABLED                    (0 << 0) /* Magic Square FRC disabled */
#define MSF_ENABLED                     (1 << 0) /* Magic Square FRC enabled */
#define HTIM01                  0x0454
#define HPW                     GENMASK(8, 0)
#define HBPR                    GENMASK(24, 16)
#define HTIM02                  0x0458
#define HDISPR                  GENMASK(10, 0)
#define HFPR                    GENMASK(24, 16)
#define VTIM01                  0x045c
#define VSPR                    GENMASK(7, 0)
#define VBPR                    GENMASK(23, 16)
#define VTIM02                  0x0460
#define VFPR                    GENMASK(23, 16)
#define VDISPR                  GENMASK(10, 0)
#define VFUEN0                  0x0464
#define VFUEN                           BIT(0)   /* Video Frame Timing Upload */

/* System */
#define TC_IDREG                0x0500
#define SYSSTAT                 0x0508
#define SYSCTRL                 0x0510
#define DP0_AUDSRC_NO_INPUT             (0 << 3)
#define DP0_AUDSRC_I2S_RX               (1 << 3)
#define DP0_VIDSRC_NO_INPUT             (0 << 0)
#define DP0_VIDSRC_DSI_RX               (1 << 0)
#define DP0_VIDSRC_DPI_RX               (2 << 0)
#define DP0_VIDSRC_COLOR_BAR            (3 << 0)
#define SYSRSTENB               0x050c
#define ENBI2C                          (1 << 0)
#define ENBLCD0                         (1 << 2)
#define ENBBM                           (1 << 3)
#define ENBDSIRX                        (1 << 4)
#define ENBREG                          (1 << 5)
#define ENBHDCP                         (1 << 8)
#define GPIOM                   0x0540
#define GPIOC                   0x0544
#define GPIOO                   0x0548
#define GPIOI                   0x054c
#define INTCTL_G                0x0560
#define INTSTS_G                0x0564

#define INT_SYSERR              BIT(16)
#define INT_GPIO_H(x)           (1 << (x == 0 ? 2 : 10))
#define INT_GPIO_LC(x)          (1 << (x == 0 ? 3 : 11))

#define INT_GP0_LCNT            0x0584
#define INT_GP1_LCNT            0x0588

/* Control */
#define DP0CTL                  0x0600
#define VID_MN_GEN                      BIT(6)   /* Auto-generate M/N values */
#define EF_EN                           BIT(5)   /* Enable Enhanced Framing */
#define VID_EN                          BIT(1)   /* Video transmission enable */
#define DP_EN                           BIT(0)   /* Enable DPTX function */

/* Clocks */
#define DP0_VIDMNGEN0           0x0610
#define DP0_VIDMNGEN1           0x0614
#define DP0_VMNGENSTATUS        0x0618

/* Main Channel */
#define DP0_SECSAMPLE           0x0640
#define DP0_VIDSYNCDELAY        0x0644
#define VID_SYNC_DLY            GENMASK(15, 0)
#define THRESH_DLY              GENMASK(31, 16)

#define DP0_TOTALVAL            0x0648
#define H_TOTAL                 GENMASK(15, 0)
#define V_TOTAL                 GENMASK(31, 16)
#define DP0_STARTVAL            0x064c
#define H_START                 GENMASK(15, 0)
#define V_START                 GENMASK(31, 16)
#define DP0_ACTIVEVAL           0x0650
#define H_ACT                   GENMASK(15, 0)
#define V_ACT                   GENMASK(31, 16)

#define DP0_SYNCVAL             0x0654
#define VS_WIDTH                GENMASK(30, 16)
#define HS_WIDTH                GENMASK(14, 0)
#define SYNCVAL_HS_POL_ACTIVE_LOW       (1 << 15)
#define SYNCVAL_VS_POL_ACTIVE_LOW       (1 << 31)
#define DP0_MISC                0x0658
#define TU_SIZE_RECOMMENDED             (63) /* LSCLK cycles per TU */
#define MAX_TU_SYMBOL           GENMASK(28, 23)
#define TU_SIZE                 GENMASK(21, 16)
#define BPC_6                           (0 << 5)
#define BPC_8                           (1 << 5)

/* AUX channel */
#define DP0_AUXCFG0             0x0660
#define DP0_AUXCFG0_BSIZE       GENMASK(11, 8)
#define DP0_AUXCFG0_ADDR_ONLY   BIT(4)
#define DP0_AUXCFG1             0x0664
#define AUX_RX_FILTER_EN                BIT(16)

#define DP0_AUXADDR             0x0668
#define DP0_AUXWDATA(i)         (0x066c + (i) * 4)
#define DP0_AUXRDATA(i)         (0x067c + (i) * 4)
#define DP0_AUXSTATUS           0x068c
#define AUX_BYTES               GENMASK(15, 8)
#define AUX_STATUS              GENMASK(7, 4)
#define AUX_TIMEOUT             BIT(1)
#define AUX_BUSY                BIT(0)
#define DP0_AUXI2CADR           0x0698

/* Link Training */
#define DP0_SRCCTRL             0x06a0
#define DP0_SRCCTRL_SCRMBLDIS           BIT(13)
#define DP0_SRCCTRL_EN810B              BIT(12)
#define DP0_SRCCTRL_NOTP                (0 << 8)
#define DP0_SRCCTRL_TP1                 (1 << 8)
#define DP0_SRCCTRL_TP2                 (2 << 8)
#define DP0_SRCCTRL_LANESKEW            BIT(7)
#define DP0_SRCCTRL_SSCG                BIT(3)
#define DP0_SRCCTRL_LANES_1             (0 << 2)
#define DP0_SRCCTRL_LANES_2             (1 << 2)
#define DP0_SRCCTRL_BW27                (1 << 1)
#define DP0_SRCCTRL_BW162               (0 << 1)
#define DP0_SRCCTRL_AUTOCORRECT         BIT(0)
#define DP0_LTSTAT              0x06d0
#define LT_LOOPDONE                     BIT(13)
#define LT_STATUS_MASK                  (0x1f << 8)
#define LT_CHANNEL1_EQ_BITS             (DP_CHANNEL_EQ_BITS << 4)
#define LT_INTERLANE_ALIGN_DONE         BIT(3)
#define LT_CHANNEL0_EQ_BITS             (DP_CHANNEL_EQ_BITS)
#define DP0_SNKLTCHGREQ         0x06d4
#define DP0_LTLOOPCTRL          0x06d8
#define DP0_SNKLTCTRL           0x06e4

#define DP1_SRCCTRL             0x07a0

/* PHY */
#define DP_PHY_CTRL             0x0800
#define DP_PHY_RST                      BIT(28)  /* DP PHY Global Soft Reset */
#define BGREN                           BIT(25)  /* AUX PHY BGR Enable */
#define PWR_SW_EN                       BIT(24)  /* PHY Power Switch Enable */
#define PHY_M1_RST                      BIT(12)  /* Reset PHY1 Main Channel */
#define PHY_RDY                         BIT(16)  /* PHY Main Channels Ready */
#define PHY_M0_RST                      BIT(8)   /* Reset PHY0 Main Channel */
#define PHY_2LANE                       BIT(2)   /* PHY Enable 2 lanes */
#define PHY_A0_EN                       BIT(1)   /* PHY Aux Channel0 Enable */
#define PHY_M0_EN                       BIT(0)   /* PHY Main Channel0 Enable */

/* PLL */
#define DP0_PLLCTRL             0x0900
#define DP1_PLLCTRL             0x0904  /* not defined in DS */
#define PXL_PLLCTRL             0x0908
#define PLLUPDATE                       BIT(2)
#define PLLBYP                          BIT(1)
#define PLLEN                           BIT(0)
#define PXL_PLLPARAM            0x0914
#define IN_SEL_REFCLK                   (0 << 14)
#define SYS_PLLPARAM            0x0918
#define REF_FREQ_38M4                   (0 << 8) /* 38.4 MHz */
#define REF_FREQ_19M2                   (1 << 8) /* 19.2 MHz */
#define REF_FREQ_26M                    (2 << 8) /* 26 MHz */
#define REF_FREQ_13M                    (3 << 8) /* 13 MHz */
#define SYSCLK_SEL_LSCLK                (0 << 4)
#define LSCLK_DIV_1                     (0 << 0)
#define LSCLK_DIV_2                     (1 << 0)

/* Test & Debug */
#define TSTCTL                  0x0a00
#define COLOR_R                 GENMASK(31, 24)
#define COLOR_G                 GENMASK(23, 16)
#define COLOR_B                 GENMASK(15, 8)
#define ENI2CFILTER             BIT(4)
#define COLOR_BAR_MODE          GENMASK(1, 0)
#define COLOR_BAR_MODE_BARS     2
#define PLL_DBG                 0x0a04

static bool tc_test_pattern;
module_param_named(test, tc_test_pattern, bool, 0644);

struct tc_edp_link {
        u8                      dpcd[DP_RECEIVER_CAP_SIZE];
        unsigned int            rate;
        u8                      num_lanes;
        u8                      assr;
        bool                    scrambler_dis;
        bool                    spread;
};

struct tc_data {
        struct device           *dev;
        struct regmap           *regmap;
        struct drm_dp_aux       aux;

        struct drm_bridge       bridge;
        struct drm_bridge       *panel_bridge;
        struct drm_connector    connector;

        /* link settings */
        struct tc_edp_link      link;

        /* current mode */
        struct drm_display_mode mode;

        u32                     rev;
        u8                      assr;

        struct gpio_desc        *sd_gpio;
        struct gpio_desc        *reset_gpio;
        struct clk              *refclk;

        /* do we have IRQ */
        bool                    have_irq;

        /* HPD pin number (0 or 1) or -ENODEV */
        int                     hpd_pin;
};

static inline struct tc_data *aux_to_tc(struct drm_dp_aux *a)
{
        return container_of(a, struct tc_data, aux);
}

static inline struct tc_data *bridge_to_tc(struct drm_bridge *b)
{
        return container_of(b, struct tc_data, bridge);
}

static inline struct tc_data *connector_to_tc(struct drm_connector *c)
{
        return container_of(c, struct tc_data, connector);
}

static inline int tc_poll_timeout(struct tc_data *tc, unsigned int addr,
                                  unsigned int cond_mask,
                                  unsigned int cond_value,
                                  unsigned long sleep_us, u64 timeout_us)
{
        unsigned int val;

        return regmap_read_poll_timeout(tc->regmap, addr, val,
                                        (val & cond_mask) == cond_value,
                                        sleep_us, timeout_us);
}

static int tc_aux_wait_busy(struct tc_data *tc)
{
        return tc_poll_timeout(tc, DP0_AUXSTATUS, AUX_BUSY, 0, 100, 100000);
}

static int tc_aux_write_data(struct tc_data *tc, const void *data,
                             size_t size)
{
        u32 auxwdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)] = { 0 };
        int ret, count = ALIGN(size, sizeof(u32));

        memcpy(auxwdata, data, size);

        ret = regmap_raw_write(tc->regmap, DP0_AUXWDATA(0), auxwdata, count);
        if (ret)
                return ret;

        return size;
}

static int tc_aux_read_data(struct tc_data *tc, void *data, size_t size)
{
        u32 auxrdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)];
        int ret, count = ALIGN(size, sizeof(u32));

        ret = regmap_raw_read(tc->regmap, DP0_AUXRDATA(0), auxrdata, count);
        if (ret)
                return ret;

        memcpy(data, auxrdata, size);

        return size;
}

static u32 tc_auxcfg0(struct drm_dp_aux_msg *msg, size_t size)
{
        u32 auxcfg0 = msg->request;

        if (size)
                auxcfg0 |= FIELD_PREP(DP0_AUXCFG0_BSIZE, size - 1);
        else
                auxcfg0 |= DP0_AUXCFG0_ADDR_ONLY;

        return auxcfg0;
}

static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
                               struct drm_dp_aux_msg *msg)
{
        struct tc_data *tc = aux_to_tc(aux);
        size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size);
        u8 request = msg->request & ~DP_AUX_I2C_MOT;
        u32 auxstatus;
        int ret;

        ret = tc_aux_wait_busy(tc);
        if (ret)
                return ret;

        switch (request) {
        case DP_AUX_NATIVE_READ:
        case DP_AUX_I2C_READ:
                break;
        case DP_AUX_NATIVE_WRITE:
        case DP_AUX_I2C_WRITE:
                if (size) {
                        ret = tc_aux_write_data(tc, msg->buffer, size);
                        if (ret < 0)
                                return ret;
                }
                break;
        default:
                return -EINVAL;
        }

        /* Store address */
        ret = regmap_write(tc->regmap, DP0_AUXADDR, msg->address);
        if (ret)
                return ret;
        /* Start transfer */
        ret = regmap_write(tc->regmap, DP0_AUXCFG0, tc_auxcfg0(msg, size));
        if (ret)
                return ret;

        ret = tc_aux_wait_busy(tc);
        if (ret)
                return ret;

        ret = regmap_read(tc->regmap, DP0_AUXSTATUS, &auxstatus);
        if (ret)
                return ret;

        if (auxstatus & AUX_TIMEOUT)
                return -ETIMEDOUT;
        /*
         * For some reason address-only DP_AUX_I2C_WRITE (MOT), still
         * reports 1 byte transferred in its status. To deal we that
         * we ignore aux_bytes field if we know that this was an
         * address-only transfer
         */
        if (size)
                size = FIELD_GET(AUX_BYTES, auxstatus);
        msg->reply = FIELD_GET(AUX_STATUS, auxstatus);

        switch (request) {
        case DP_AUX_NATIVE_READ:
        case DP_AUX_I2C_READ:
                if (size)
                        return tc_aux_read_data(tc, msg->buffer, size);
                break;
        }

        return size;
}

static const char * const training_pattern1_errors[] = {
        "No errors",
        "Aux write error",
        "Aux read error",
        "Max voltage reached error",
        "Loop counter expired error",
        "res", "res", "res"
};

static const char * const training_pattern2_errors[] = {
        "No errors",
        "Aux write error",
        "Aux read error",
        "Clock recovery failed error",
        "Loop counter expired error",
        "res", "res", "res"
};

static u32 tc_srcctrl(struct tc_data *tc)
{
        /*
         * No training pattern, skew lane 1 data by two LSCLK cycles with
         * respect to lane 0 data, AutoCorrect Mode = 0
         */
        u32 reg = DP0_SRCCTRL_NOTP | DP0_SRCCTRL_LANESKEW | DP0_SRCCTRL_EN810B;

        if (tc->link.scrambler_dis)
                reg |= DP0_SRCCTRL_SCRMBLDIS;   /* Scrambler Disabled */
        if (tc->link.spread)
                reg |= DP0_SRCCTRL_SSCG;        /* Spread Spectrum Enable */
        if (tc->link.num_lanes == 2)
                reg |= DP0_SRCCTRL_LANES_2;     /* Two Main Channel Lanes */
        if (tc->link.rate != 162000)
                reg |= DP0_SRCCTRL_BW27;        /* 2.7 Gbps link */
        return reg;
}

static int tc_pllupdate(struct tc_data *tc, unsigned int pllctrl)
{
        int ret;

        ret = regmap_write(tc->regmap, pllctrl, PLLUPDATE | PLLEN);
        if (ret)
                return ret;

        /* Wait for PLL to lock: up to 2.09 ms, depending on refclk */
        usleep_range(3000, 6000);

        return 0;
}

static int tc_pxl_pll_en(struct tc_data *tc, u32 refclk, u32 pixelclock)
{
        int ret;
        int i_pre, best_pre = 1;
        int i_post, best_post = 1;
        int div, best_div = 1;
        int mul, best_mul = 1;
        int delta, best_delta;
        int ext_div[] = {1, 2, 3, 5, 7};
        int best_pixelclock = 0;
        int vco_hi = 0;
        u32 pxl_pllparam;

        dev_dbg(tc->dev, "PLL: requested %d pixelclock, ref %d\n", pixelclock,
                refclk);
        best_delta = pixelclock;
        /* Loop over all possible ext_divs, skipping invalid configurations */
        for (i_pre = 0; i_pre < ARRAY_SIZE(ext_div); i_pre++) {
                /*
                 * refclk / ext_pre_div should be in the 1 to 200 MHz range.
                 * We don't allow any refclk > 200 MHz, only check lower bounds.
                 */
                if (refclk / ext_div[i_pre] < 1000000)
                        continue;
                for (i_post = 0; i_post < ARRAY_SIZE(ext_div); i_post++) {
                        for (div = 1; div <= 16; div++) {
                                u32 clk;
                                u64 tmp;

                                tmp = pixelclock * ext_div[i_pre] *
                                      ext_div[i_post] * div;
                                do_div(tmp, refclk);
                                mul = tmp;

                                /* Check limits */
                                if ((mul < 1) || (mul > 128))
                                        continue;

                                clk = (refclk / ext_div[i_pre] / div) * mul;
                                /*
                                 * refclk * mul / (ext_pre_div * pre_div)
                                 * should be in the 150 to 650 MHz range
                                 */
                                if ((clk > 650000000) || (clk < 150000000))
                                        continue;

                                clk = clk / ext_div[i_post];
                                delta = clk - pixelclock;

                                if (abs(delta) < abs(best_delta)) {
                                        best_pre = i_pre;
                                        best_post = i_post;
                                        best_div = div;
                                        best_mul = mul;
                                        best_delta = delta;
                                        best_pixelclock = clk;
                                }
                        }
                }
        }
        if (best_pixelclock == 0) {
                dev_err(tc->dev, "Failed to calc clock for %d pixelclock\n",
                        pixelclock);
                return -EINVAL;
        }

        dev_dbg(tc->dev, "PLL: got %d, delta %d\n", best_pixelclock,
                best_delta);
        dev_dbg(tc->dev, "PLL: %d / %d / %d * %d / %d\n", refclk,
                ext_div[best_pre], best_div, best_mul, ext_div[best_post]);

        /* if VCO >= 300 MHz */
        if (refclk / ext_div[best_pre] / best_div * best_mul >= 300000000)
                vco_hi = 1;
        /* see DS */
        if (best_div == 16)
                best_div = 0;
        if (best_mul == 128)
                best_mul = 0;

        /* Power up PLL and switch to bypass */
        ret = regmap_write(tc->regmap, PXL_PLLCTRL, PLLBYP | PLLEN);
        if (ret)
                return ret;

        pxl_pllparam  = vco_hi << 24; /* For PLL VCO >= 300 MHz = 1 */
        pxl_pllparam |= ext_div[best_pre] << 20; /* External Pre-divider */
        pxl_pllparam |= ext_div[best_post] << 16; /* External Post-divider */
        pxl_pllparam |= IN_SEL_REFCLK; /* Use RefClk as PLL input */
        pxl_pllparam |= best_div << 8; /* Divider for PLL RefClk */
        pxl_pllparam |= best_mul; /* Multiplier for PLL */

        ret = regmap_write(tc->regmap, PXL_PLLPARAM, pxl_pllparam);
        if (ret)
                return ret;

        /* Force PLL parameter update and disable bypass */
        return tc_pllupdate(tc, PXL_PLLCTRL);
}

static int tc_pxl_pll_dis(struct tc_data *tc)
{
        /* Enable PLL bypass, power down PLL */
        return regmap_write(tc->regmap, PXL_PLLCTRL, PLLBYP);
}

static int tc_stream_clock_calc(struct tc_data *tc)
{
        /*
         * If the Stream clock and Link Symbol clock are
         * asynchronous with each other, the value of M changes over
         * time. This way of generating link clock and stream
         * clock is called Asynchronous Clock mode. The value M
         * must change while the value N stays constant. The
         * value of N in this Asynchronous Clock mode must be set
         * to 2^15 or 32,768.
         *
         * LSCLK = 1/10 of high speed link clock
         *
         * f_STRMCLK = M/N * f_LSCLK
         * M/N = f_STRMCLK / f_LSCLK
         *
         */
        return regmap_write(tc->regmap, DP0_VIDMNGEN1, 32768);
}

static int tc_set_syspllparam(struct tc_data *tc)
{
        unsigned long rate;
        u32 pllparam = SYSCLK_SEL_LSCLK | LSCLK_DIV_2;

        rate = clk_get_rate(tc->refclk);
        switch (rate) {
        case 38400000:
                pllparam |= REF_FREQ_38M4;
                break;
        case 26000000:
                pllparam |= REF_FREQ_26M;
                break;
        case 19200000:
                pllparam |= REF_FREQ_19M2;
                break;
        case 13000000:
                pllparam |= REF_FREQ_13M;
                break;
        default:
                dev_err(tc->dev, "Invalid refclk rate: %lu Hz\n", rate);
                return -EINVAL;
        }

        return regmap_write(tc->regmap, SYS_PLLPARAM, pllparam);
}

static int tc_aux_link_setup(struct tc_data *tc)
{
        int ret;
        u32 dp0_auxcfg1;

        /* Setup DP-PHY / PLL */
        ret = tc_set_syspllparam(tc);
        if (ret)
                goto err;

        ret = regmap_write(tc->regmap, DP_PHY_CTRL,
                           BGREN | PWR_SW_EN | PHY_A0_EN);
        if (ret)
                goto err;
        /*
         * Initially PLLs are in bypass. Force PLL parameter update,
         * disable PLL bypass, enable PLL
         */
        ret = tc_pllupdate(tc, DP0_PLLCTRL);
        if (ret)
                goto err;

        ret = tc_pllupdate(tc, DP1_PLLCTRL);
        if (ret)
                goto err;

        ret = tc_poll_timeout(tc, DP_PHY_CTRL, PHY_RDY, PHY_RDY, 100, 100000);
        if (ret == -ETIMEDOUT) {
                dev_err(tc->dev, "Timeout waiting for PHY to become ready");
                return ret;
        } else if (ret) {
                goto err;
        }

        /* Setup AUX link */
        dp0_auxcfg1  = AUX_RX_FILTER_EN;
        dp0_auxcfg1 |= 0x06 << 8; /* Aux Bit Period Calculator Threshold */
        dp0_auxcfg1 |= 0x3f << 0; /* Aux Response Timeout Timer */

        ret = regmap_write(tc->regmap, DP0_AUXCFG1, dp0_auxcfg1);
        if (ret)
                goto err;

        return 0;
err:
        dev_err(tc->dev, "tc_aux_link_setup failed: %d\n", ret);
        return ret;
}

static int tc_get_display_props(struct tc_data *tc)
{
        u8 revision, num_lanes;
        unsigned int rate;
        int ret;
        u8 reg;

        /* Read DP Rx Link Capability */
        ret = drm_dp_dpcd_read(&tc->aux, DP_DPCD_REV, tc->link.dpcd,
                               DP_RECEIVER_CAP_SIZE);
        if (ret < 0)
                goto err_dpcd_read;

        revision = tc->link.dpcd[DP_DPCD_REV];
        rate = drm_dp_max_link_rate(tc->link.dpcd);
        num_lanes = drm_dp_max_lane_count(tc->link.dpcd);

        if (rate != 162000 && rate != 270000) {
                dev_dbg(tc->dev, "Falling to 2.7 Gbps rate\n");
                rate = 270000;
        }

        tc->link.rate = rate;

        if (num_lanes > 2) {
                dev_dbg(tc->dev, "Falling to 2 lanes\n");
                num_lanes = 2;
        }

        tc->link.num_lanes = num_lanes;

        ret = drm_dp_dpcd_readb(&tc->aux, DP_MAX_DOWNSPREAD, &reg);
        if (ret < 0)
                goto err_dpcd_read;
        tc->link.spread = reg & DP_MAX_DOWNSPREAD_0_5;

        ret = drm_dp_dpcd_readb(&tc->aux, DP_MAIN_LINK_CHANNEL_CODING, &reg);
        if (ret < 0)
                goto err_dpcd_read;

        tc->link.scrambler_dis = false;
        /* read assr */
        ret = drm_dp_dpcd_readb(&tc->aux, DP_EDP_CONFIGURATION_SET, &reg);
        if (ret < 0)
                goto err_dpcd_read;
        tc->link.assr = reg & DP_ALTERNATE_SCRAMBLER_RESET_ENABLE;

        dev_dbg(tc->dev, "DPCD rev: %d.%d, rate: %s, lanes: %d, framing: %s\n",
                revision >> 4, revision & 0x0f,
                (tc->link.rate == 162000) ? "1.62Gbps" : "2.7Gbps",
                tc->link.num_lanes,
                drm_dp_enhanced_frame_cap(tc->link.dpcd) ?
                "enhanced" : "default");
        dev_dbg(tc->dev, "Downspread: %s, scrambler: %s\n",
                tc->link.spread ? "0.5%" : "0.0%",
                tc->link.scrambler_dis ? "disabled" : "enabled");
        dev_dbg(tc->dev, "Display ASSR: %d, TC358767 ASSR: %d\n",
                tc->link.assr, tc->assr);

        return 0;

err_dpcd_read:
        dev_err(tc->dev, "failed to read DPCD: %d\n", ret);
        return ret;
}

static int tc_set_video_mode(struct tc_data *tc,
                             const struct drm_display_mode *mode)
{
        int ret;
        int vid_sync_dly;
        int max_tu_symbol;

        int left_margin = mode->htotal - mode->hsync_end;
        int right_margin = mode->hsync_start - mode->hdisplay;
        int hsync_len = mode->hsync_end - mode->hsync_start;
        int upper_margin = mode->vtotal - mode->vsync_end;
        int lower_margin = mode->vsync_start - mode->vdisplay;
        int vsync_len = mode->vsync_end - mode->vsync_start;
        u32 dp0_syncval;
        u32 bits_per_pixel = 24;
        u32 in_bw, out_bw;

        /*
         * Recommended maximum number of symbols transferred in a transfer unit:
         * DIV_ROUND_UP((input active video bandwidth in bytes) * tu_size,
         *              (output active video bandwidth in bytes))
         * Must be less than tu_size.
         */

        in_bw = mode->clock * bits_per_pixel / 8;
        out_bw = tc->link.num_lanes * tc->link.rate;
        max_tu_symbol = DIV_ROUND_UP(in_bw * TU_SIZE_RECOMMENDED, out_bw);

        dev_dbg(tc->dev, "set mode %dx%d\n",
                mode->hdisplay, mode->vdisplay);
        dev_dbg(tc->dev, "H margin %d,%d sync %d\n",
                left_margin, right_margin, hsync_len);
        dev_dbg(tc->dev, "V margin %d,%d sync %d\n",
                upper_margin, lower_margin, vsync_len);
        dev_dbg(tc->dev, "total: %dx%d\n", mode->htotal, mode->vtotal);


        /*
         * LCD Ctl Frame Size
         * datasheet is not clear of vsdelay in case of DPI
         * assume we do not need any delay when DPI is a source of
         * sync signals
         */
        ret = regmap_write(tc->regmap, VPCTRL0,
                           FIELD_PREP(VSDELAY, 0) |
                           OPXLFMT_RGB888 | FRMSYNC_DISABLED | MSF_DISABLED);
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, HTIM01,
                           FIELD_PREP(HBPR, ALIGN(left_margin, 2)) |
                           FIELD_PREP(HPW, ALIGN(hsync_len, 2)));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, HTIM02,
                           FIELD_PREP(HDISPR, ALIGN(mode->hdisplay, 2)) |
                           FIELD_PREP(HFPR, ALIGN(right_margin, 2)));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, VTIM01,
                           FIELD_PREP(VBPR, upper_margin) |
                           FIELD_PREP(VSPR, vsync_len));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, VTIM02,
                           FIELD_PREP(VFPR, lower_margin) |
                           FIELD_PREP(VDISPR, mode->vdisplay));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, VFUEN0, VFUEN); /* update settings */
        if (ret)
                return ret;

        /* Test pattern settings */
        ret = regmap_write(tc->regmap, TSTCTL,
                           FIELD_PREP(COLOR_R, 120) |
                           FIELD_PREP(COLOR_G, 20) |
                           FIELD_PREP(COLOR_B, 99) |
                           ENI2CFILTER |
                           FIELD_PREP(COLOR_BAR_MODE, COLOR_BAR_MODE_BARS));
        if (ret)
                return ret;

        /* DP Main Stream Attributes */
        vid_sync_dly = hsync_len + left_margin + mode->hdisplay;
        ret = regmap_write(tc->regmap, DP0_VIDSYNCDELAY,
                 FIELD_PREP(THRESH_DLY, max_tu_symbol) |
                 FIELD_PREP(VID_SYNC_DLY, vid_sync_dly));

        ret = regmap_write(tc->regmap, DP0_TOTALVAL,
                           FIELD_PREP(H_TOTAL, mode->htotal) |
                           FIELD_PREP(V_TOTAL, mode->vtotal));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_STARTVAL,
                           FIELD_PREP(H_START, left_margin + hsync_len) |
                           FIELD_PREP(V_START, upper_margin + vsync_len));
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_ACTIVEVAL,
                           FIELD_PREP(V_ACT, mode->vdisplay) |
                           FIELD_PREP(H_ACT, mode->hdisplay));
        if (ret)
                return ret;

        dp0_syncval = FIELD_PREP(VS_WIDTH, vsync_len) |
                      FIELD_PREP(HS_WIDTH, hsync_len);

        if (mode->flags & DRM_MODE_FLAG_NVSYNC)
                dp0_syncval |= SYNCVAL_VS_POL_ACTIVE_LOW;

        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
                dp0_syncval |= SYNCVAL_HS_POL_ACTIVE_LOW;

        ret = regmap_write(tc->regmap, DP0_SYNCVAL, dp0_syncval);
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DPIPXLFMT,
                           VS_POL_ACTIVE_LOW | HS_POL_ACTIVE_LOW |
                           DE_POL_ACTIVE_HIGH | SUB_CFG_TYPE_CONFIG1 |
                           DPI_BPP_RGB888);
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_MISC,
                           FIELD_PREP(MAX_TU_SYMBOL, max_tu_symbol) |
                           FIELD_PREP(TU_SIZE, TU_SIZE_RECOMMENDED) |
                           BPC_8);
        if (ret)
                return ret;

        return 0;
}

static int tc_wait_link_training(struct tc_data *tc)
{
        u32 value;
        int ret;

        ret = tc_poll_timeout(tc, DP0_LTSTAT, LT_LOOPDONE,
                              LT_LOOPDONE, 500, 100000);
        if (ret) {
                dev_err(tc->dev, "Link training timeout waiting for LT_LOOPDONE!\n");
                return ret;
        }

        ret = regmap_read(tc->regmap, DP0_LTSTAT, &value);
        if (ret)
                return ret;

        return (value >> 8) & 0x7;
}

static int tc_main_link_enable(struct tc_data *tc)
{
        struct drm_dp_aux *aux = &tc->aux;
        struct device *dev = tc->dev;
        u32 dp_phy_ctrl;
        u32 value;
        int ret;
        u8 tmp[DP_LINK_STATUS_SIZE];

        dev_dbg(tc->dev, "link enable\n");

        ret = regmap_read(tc->regmap, DP0CTL, &value);
        if (ret)
                return ret;

        if (WARN_ON(value & DP_EN)) {
                ret = regmap_write(tc->regmap, DP0CTL, 0);
                if (ret)
                        return ret;
        }

        ret = regmap_write(tc->regmap, DP0_SRCCTRL, tc_srcctrl(tc));
        if (ret)
                return ret;
        /* SSCG and BW27 on DP1 must be set to the same as on DP0 */
        ret = regmap_write(tc->regmap, DP1_SRCCTRL,
                 (tc->link.spread ? DP0_SRCCTRL_SSCG : 0) |
                 ((tc->link.rate != 162000) ? DP0_SRCCTRL_BW27 : 0));
        if (ret)
                return ret;

        ret = tc_set_syspllparam(tc);
        if (ret)
                return ret;

        /* Setup Main Link */
        dp_phy_ctrl = BGREN | PWR_SW_EN | PHY_A0_EN | PHY_M0_EN;
        if (tc->link.num_lanes == 2)
                dp_phy_ctrl |= PHY_2LANE;

        ret = regmap_write(tc->regmap, DP_PHY_CTRL, dp_phy_ctrl);
        if (ret)
                return ret;

        /* PLL setup */
        ret = tc_pllupdate(tc, DP0_PLLCTRL);
        if (ret)
                return ret;

        ret = tc_pllupdate(tc, DP1_PLLCTRL);
        if (ret)
                return ret;

        /* Reset/Enable Main Links */
        dp_phy_ctrl |= DP_PHY_RST | PHY_M1_RST | PHY_M0_RST;
        ret = regmap_write(tc->regmap, DP_PHY_CTRL, dp_phy_ctrl);
        usleep_range(100, 200);
        dp_phy_ctrl &= ~(DP_PHY_RST | PHY_M1_RST | PHY_M0_RST);
        ret = regmap_write(tc->regmap, DP_PHY_CTRL, dp_phy_ctrl);

        ret = tc_poll_timeout(tc, DP_PHY_CTRL, PHY_RDY, PHY_RDY, 500, 100000);
        if (ret) {
                dev_err(dev, "timeout waiting for phy become ready");
                return ret;
        }

        /* Set misc: 8 bits per color */
        ret = regmap_update_bits(tc->regmap, DP0_MISC, BPC_8, BPC_8);
        if (ret)
                return ret;

        /*
         * ASSR mode
         * on TC358767 side ASSR configured through strap pin
         * seems there is no way to change this setting from SW
         *
         * check is tc configured for same mode
         */
        if (tc->assr != tc->link.assr) {
                dev_dbg(dev, "Trying to set display to ASSR: %d\n",
                        tc->assr);
                /* try to set ASSR on display side */
                tmp[0] = tc->assr;
                ret = drm_dp_dpcd_writeb(aux, DP_EDP_CONFIGURATION_SET, tmp[0]);
                if (ret < 0)
                        goto err_dpcd_read;
                /* read back */
                ret = drm_dp_dpcd_readb(aux, DP_EDP_CONFIGURATION_SET, tmp);
                if (ret < 0)
                        goto err_dpcd_read;

                if (tmp[0] != tc->assr) {
                        dev_dbg(dev, "Failed to switch display ASSR to %d, falling back to unscrambled mode\n",
                                tc->assr);
                        /* trying with disabled scrambler */
                        tc->link.scrambler_dis = true;
                }
        }

        /* Setup Link & DPRx Config for Training */
        tmp[0] = drm_dp_link_rate_to_bw_code(tc->link.rate);
        tmp[1] = tc->link.num_lanes;

        if (drm_dp_enhanced_frame_cap(tc->link.dpcd))
                tmp[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;

        ret = drm_dp_dpcd_write(aux, DP_LINK_BW_SET, tmp, 2);
        if (ret < 0)
                goto err_dpcd_write;

        /* DOWNSPREAD_CTRL */
        tmp[0] = tc->link.spread ? DP_SPREAD_AMP_0_5 : 0x00;
        /* MAIN_LINK_CHANNEL_CODING_SET */
        tmp[1] =  DP_SET_ANSI_8B10B;
        ret = drm_dp_dpcd_write(aux, DP_DOWNSPREAD_CTRL, tmp, 2);
        if (ret < 0)
                goto err_dpcd_write;

        /* Reset voltage-swing & pre-emphasis */
        tmp[0] = tmp[1] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 |
                          DP_TRAIN_PRE_EMPH_LEVEL_0;
        ret = drm_dp_dpcd_write(aux, DP_TRAINING_LANE0_SET, tmp, 2);
        if (ret < 0)
                goto err_dpcd_write;

        /* Clock-Recovery */

        /* Set DPCD 0x102 for Training Pattern 1 */
        ret = regmap_write(tc->regmap, DP0_SNKLTCTRL,
                           DP_LINK_SCRAMBLING_DISABLE |
                           DP_TRAINING_PATTERN_1);
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_LTLOOPCTRL,
                           (15 << 28) | /* Defer Iteration Count */
                           (15 << 24) | /* Loop Iteration Count */
                           (0xd << 0)); /* Loop Timer Delay */
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_SRCCTRL,
                           tc_srcctrl(tc) | DP0_SRCCTRL_SCRMBLDIS |
                           DP0_SRCCTRL_AUTOCORRECT |
                           DP0_SRCCTRL_TP1);
        if (ret)
                return ret;

        /* Enable DP0 to start Link Training */
        ret = regmap_write(tc->regmap, DP0CTL,
                           (drm_dp_enhanced_frame_cap(tc->link.dpcd) ?
                                EF_EN : 0) | DP_EN);
        if (ret)
                return ret;

        /* wait */

        ret = tc_wait_link_training(tc);
        if (ret < 0)
                return ret;

        if (ret) {
                dev_err(tc->dev, "Link training phase 1 failed: %s\n",
                        training_pattern1_errors[ret]);
                return -ENODEV;
        }

        /* Channel Equalization */

        /* Set DPCD 0x102 for Training Pattern 2 */
        ret = regmap_write(tc->regmap, DP0_SNKLTCTRL,
                           DP_LINK_SCRAMBLING_DISABLE |
                           DP_TRAINING_PATTERN_2);
        if (ret)
                return ret;

        ret = regmap_write(tc->regmap, DP0_SRCCTRL,
                           tc_srcctrl(tc) | DP0_SRCCTRL_SCRMBLDIS |
                           DP0_SRCCTRL_AUTOCORRECT |
                           DP0_SRCCTRL_TP2);
        if (ret)
                return ret;

        /* wait */
        ret = tc_wait_link_training(tc);
        if (ret < 0)
                return ret;

        if (ret) {
                dev_err(tc->dev, "Link training phase 2 failed: %s\n",
                        training_pattern2_errors[ret]);
                return -ENODEV;
        }

        /*
         * Toshiba's documentation suggests to first clear DPCD 0x102, then
         * clear the training pattern bit in DP0_SRCCTRL. Testing shows
         * that the link sometimes drops if those steps are done in that order,
         * but if the steps are done in reverse order, the link stays up.
         *
         * So we do the steps differently than documented here.
         */

        /* Clear Training Pattern, set AutoCorrect Mode = 1 */
        ret = regmap_write(tc->regmap, DP0_SRCCTRL, tc_srcctrl(tc) |
                           DP0_SRCCTRL_AUTOCORRECT);
        if (ret)
                return ret;

        /* Clear DPCD 0x102 */
        /* Note: Can Not use DP0_SNKLTCTRL (0x06E4) short cut */
        tmp[0] = tc->link.scrambler_dis ? DP_LINK_SCRAMBLING_DISABLE : 0x00;
        ret = drm_dp_dpcd_writeb(aux, DP_TRAINING_PATTERN_SET, tmp[0]);
        if (ret < 0)
                goto err_dpcd_write;

        /* Check link status */
        ret = drm_dp_dpcd_read_link_status(aux, tmp);
        if (ret < 0)
                goto err_dpcd_read;

        ret = 0;

        value = tmp[0] & DP_CHANNEL_EQ_BITS;

        if (value != DP_CHANNEL_EQ_BITS) {
                dev_err(tc->dev, "Lane 0 failed: %x\n", value);
                ret = -ENODEV;
        }

        if (tc->link.num_lanes == 2) {
                value = (tmp[0] >> 4) & DP_CHANNEL_EQ_BITS;

                if (value != DP_CHANNEL_EQ_BITS) {
                        dev_err(tc->dev, "Lane 1 failed: %x\n", value);
                        ret = -ENODEV;
                }

                if (!(tmp[2] & DP_INTERLANE_ALIGN_DONE)) {
                        dev_err(tc->dev, "Interlane align failed\n");
                        ret = -ENODEV;
                }
        }

        if (ret) {
                dev_err(dev, "0x0202 LANE0_1_STATUS:            0x%02x\n", tmp[0]);
                dev_err(dev, "0x0203 LANE2_3_STATUS             0x%02x\n", tmp[1]);
                dev_err(dev, "0x0204 LANE_ALIGN_STATUS_UPDATED: 0x%02x\n", tmp[2]);
                dev_err(dev, "0x0205 SINK_STATUS:               0x%02x\n", tmp[3]);
                dev_err(dev, "0x0206 ADJUST_REQUEST_LANE0_1:    0x%02x\n", tmp[4]);
                dev_err(dev, "0x0207 ADJUST_REQUEST_LANE2_3:    0x%02x\n", tmp[5]);
                return ret;
        }

        return 0;
err_dpcd_read:
        dev_err(tc->dev, "Failed to read DPCD: %d\n", ret);
        return ret;
err_dpcd_write:
        dev_err(tc->dev, "Failed to write DPCD: %d\n", ret);
        return ret;
}

static int tc_main_link_disable(struct tc_data *tc)
{
        int ret;

        dev_dbg(tc->dev, "link disable\n");

        ret = regmap_write(tc->regmap, DP0_SRCCTRL, 0);
        if (ret)
                return ret;

        return regmap_write(tc->regmap, DP0CTL, 0);
}

static int tc_stream_enable(struct tc_data *tc)
{
        int ret;
        u32 value;

        dev_dbg(tc->dev, "enable video stream\n");

        /* PXL PLL setup */
        if (tc_test_pattern) {
                ret = tc_pxl_pll_en(tc, clk_get_rate(tc->refclk),
                                    1000 * tc->mode.clock);
                if (ret)
                        return ret;
        }

        ret = tc_set_video_mode(tc, &tc->mode);
        if (ret)
                return ret;

        /* Set M/N */
        ret = tc_stream_clock_calc(tc);
        if (ret)
                return ret;

        value = VID_MN_GEN | DP_EN;
        if (drm_dp_enhanced_frame_cap(tc->link.dpcd))
                value |= EF_EN;
        ret = regmap_write(tc->regmap, DP0CTL, value);
        if (ret)
                return ret;
        /*
         * VID_EN assertion should be delayed by at least N * LSCLK
         * cycles from the time VID_MN_GEN is enabled in order to
         * generate stable values for VID_M. LSCLK is 270 MHz or
         * 162 MHz, VID_N is set to 32768 in  tc_stream_clock_calc(),
         * so a delay of at least 203 us should suffice.
         */
        usleep_range(500, 1000);
        value |= VID_EN;
        ret = regmap_write(tc->regmap, DP0CTL, value);
        if (ret)
                return ret;
        /* Set input interface */
        value = DP0_AUDSRC_NO_INPUT;
        if (tc_test_pattern)
                value |= DP0_VIDSRC_COLOR_BAR;
        else
                value |= DP0_VIDSRC_DPI_RX;
        ret = regmap_write(tc->regmap, SYSCTRL, value);
        if (ret)
                return ret;

        return 0;
}

static int tc_stream_disable(struct tc_data *tc)
{
        int ret;

        dev_dbg(tc->dev, "disable video stream\n");

        ret = regmap_update_bits(tc->regmap, DP0CTL, VID_EN, 0);
        if (ret)
                return ret;

        tc_pxl_pll_dis(tc);

        return 0;
}

static void tc_bridge_enable(struct drm_bridge *bridge)
{
        struct tc_data *tc = bridge_to_tc(bridge);
        int ret;

        ret = tc_get_display_props(tc);
        if (ret < 0) {
                dev_err(tc->dev, "failed to read display props: %d\n", ret);
                return;
        }

        ret = tc_main_link_enable(tc);
        if (ret < 0) {
                dev_err(tc->dev, "main link enable error: %d\n", ret);
                return;
        }

        ret = tc_stream_enable(tc);
        if (ret < 0) {
                dev_err(tc->dev, "main link stream start error: %d\n", ret);
                tc_main_link_disable(tc);
                return;
        }
}

static void tc_bridge_disable(struct drm_bridge *bridge)
{
        struct tc_data *tc = bridge_to_tc(bridge);
        int ret;

        ret = tc_stream_disable(tc);
        if (ret < 0)
                dev_err(tc->dev, "main link stream stop error: %d\n", ret);

        ret = tc_main_link_disable(tc);
        if (ret < 0)
                dev_err(tc->dev, "main link disable error: %d\n", ret);
}

static bool tc_bridge_mode_fixup(struct drm_bridge *bridge,
                                 const struct drm_display_mode *mode,
                                 struct drm_display_mode *adj)
{
        /* Fixup sync polarities, both hsync and vsync are active low */
        adj->flags = mode->flags;
        adj->flags |= (DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
        adj->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);

        return true;
}

static enum drm_mode_status tc_mode_valid(struct drm_bridge *bridge,
                                          const struct drm_display_info *info,
                                          const struct drm_display_mode *mode)
{
        struct tc_data *tc = bridge_to_tc(bridge);
        u32 req, avail;
        u32 bits_per_pixel = 24;

        /* DPI interface clock limitation: upto 154 MHz */
        if (mode->clock > 154000)
                return MODE_CLOCK_HIGH;

        req = mode->clock * bits_per_pixel / 8;
        avail = tc->link.num_lanes * tc->link.rate;

        if (req > avail)
                return MODE_BAD;

        return MODE_OK;
}

static void tc_bridge_mode_set(struct drm_bridge *bridge,
                               const struct drm_display_mode *mode,
                               const struct drm_display_mode *adj)
{
        struct tc_data *tc = bridge_to_tc(bridge);

        tc->mode = *mode;
}

static struct edid *tc_get_edid(struct drm_bridge *bridge,
                                struct drm_connector *connector)
{
        struct tc_data *tc = bridge_to_tc(bridge);

        return drm_get_edid(connector, &tc->aux.ddc);
}

static int tc_connector_get_modes(struct drm_connector *connector)
{
        struct tc_data *tc = connector_to_tc(connector);
        int num_modes;
        struct edid *edid;
        int ret;

        ret = tc_get_display_props(tc);
        if (ret < 0) {
                dev_err(tc->dev, "failed to read display props: %d\n", ret);
                return 0;
        }

        if (tc->panel_bridge) {
                num_modes = drm_bridge_get_modes(tc->panel_bridge, connector);
                if (num_modes > 0)
                        return num_modes;
        }

        edid = tc_get_edid(&tc->bridge, connector);
        num_modes = drm_add_edid_modes(connector, edid);
        kfree(edid);

        return num_modes;
}

static const struct drm_connector_helper_funcs tc_connector_helper_funcs = {
        .get_modes = tc_connector_get_modes,
};

static enum drm_connector_status tc_bridge_detect(struct drm_bridge *bridge)
{
        struct tc_data *tc = bridge_to_tc(bridge);
        bool conn;
        u32 val;
        int ret;

        ret = regmap_read(tc->regmap, GPIOI, &val);
        if (ret)
                return connector_status_unknown;

        conn = val & BIT(tc->hpd_pin);

        if (conn)
                return connector_status_connected;
        else
                return connector_status_disconnected;
}

static enum drm_connector_status
tc_connector_detect(struct drm_connector *connector, bool force)
{
        struct tc_data *tc = connector_to_tc(connector);

        if (tc->hpd_pin >= 0)
                return tc_bridge_detect(&tc->bridge);

        if (tc->panel_bridge)
                return connector_status_connected;
        else
                return connector_status_unknown;
}

static const struct drm_connector_funcs tc_connector_funcs = {
        .detect = tc_connector_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .destroy = drm_connector_cleanup,
        .reset = drm_atomic_helper_connector_reset,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};

static int tc_bridge_attach(struct drm_bridge *bridge,
                            enum drm_bridge_attach_flags flags)
{
        u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
        struct tc_data *tc = bridge_to_tc(bridge);
        struct drm_device *drm = bridge->dev;
        int ret;

        if (tc->panel_bridge) {
                /* If a connector is required then this driver shall create it */
                ret = drm_bridge_attach(tc->bridge.encoder, tc->panel_bridge,
                                        &tc->bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
                if (ret)
                        return ret;
        }

        if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
                return 0;

        tc->aux.drm_dev = drm;
        ret = drm_dp_aux_register(&tc->aux);
        if (ret < 0)
                return ret;

        /* Create DP/eDP connector */
        drm_connector_helper_add(&tc->connector, &tc_connector_helper_funcs);
        ret = drm_connector_init(drm, &tc->connector, &tc_connector_funcs, tc->bridge.type);
        if (ret)
                goto aux_unregister;

        /* Don't poll if don't have HPD connected */
        if (tc->hpd_pin >= 0) {
                if (tc->have_irq)
                        tc->connector.polled = DRM_CONNECTOR_POLL_HPD;
                else
                        tc->connector.polled = DRM_CONNECTOR_POLL_CONNECT |
                                               DRM_CONNECTOR_POLL_DISCONNECT;
        }

        drm_display_info_set_bus_formats(&tc->connector.display_info,
                                         &bus_format, 1);
        tc->connector.display_info.bus_flags =
                DRM_BUS_FLAG_DE_HIGH |
                DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE |
                DRM_BUS_FLAG_SYNC_DRIVE_NEGEDGE;
        drm_connector_attach_encoder(&tc->connector, tc->bridge.encoder);

        return 0;
aux_unregister:
        drm_dp_aux_unregister(&tc->aux);
        return ret;
}

static void tc_bridge_detach(struct drm_bridge *bridge)
{
        drm_dp_aux_unregister(&bridge_to_tc(bridge)->aux);
}

static const struct drm_bridge_funcs tc_bridge_funcs = {
        .attach = tc_bridge_attach,
        .detach = tc_bridge_detach,
        .mode_valid = tc_mode_valid,
        .mode_set = tc_bridge_mode_set,
        .enable = tc_bridge_enable,
        .disable = tc_bridge_disable,
        .mode_fixup = tc_bridge_mode_fixup,
        .detect = tc_bridge_detect,
        .get_edid = tc_get_edid,
};

static bool tc_readable_reg(struct device *dev, unsigned int reg)
{
        return reg != SYSCTRL;
}

static const struct regmap_range tc_volatile_ranges[] = {
        regmap_reg_range(DP0_AUXWDATA(0), DP0_AUXSTATUS),
        regmap_reg_range(DP0_LTSTAT, DP0_SNKLTCHGREQ),
        regmap_reg_range(DP_PHY_CTRL, DP_PHY_CTRL),
        regmap_reg_range(DP0_PLLCTRL, PXL_PLLCTRL),
        regmap_reg_range(VFUEN0, VFUEN0),
        regmap_reg_range(INTSTS_G, INTSTS_G),
        regmap_reg_range(GPIOI, GPIOI),
};

static const struct regmap_access_table tc_volatile_table = {
        .yes_ranges = tc_volatile_ranges,
        .n_yes_ranges = ARRAY_SIZE(tc_volatile_ranges),
};

static bool tc_writeable_reg(struct device *dev, unsigned int reg)
{
        return (reg != TC_IDREG) &&
               (reg != DP0_LTSTAT) &&
               (reg != DP0_SNKLTCHGREQ);
}

static const struct regmap_config tc_regmap_config = {
        .name = "tc358767",
        .reg_bits = 16,
        .val_bits = 32,
        .reg_stride = 4,
        .max_register = PLL_DBG,
        .cache_type = REGCACHE_RBTREE,
        .readable_reg = tc_readable_reg,
        .volatile_table = &tc_volatile_table,
        .writeable_reg = tc_writeable_reg,
        .reg_format_endian = REGMAP_ENDIAN_BIG,
        .val_format_endian = REGMAP_ENDIAN_LITTLE,
};

static irqreturn_t tc_irq_handler(int irq, void *arg)
{
        struct tc_data *tc = arg;
        u32 val;
        int r;

        r = regmap_read(tc->regmap, INTSTS_G, &val);
        if (r)
                return IRQ_NONE;

        if (!val)
                return IRQ_NONE;

        if (val & INT_SYSERR) {
                u32 stat = 0;

                regmap_read(tc->regmap, SYSSTAT, &stat);

                dev_err(tc->dev, "syserr %x\n", stat);
        }

        if (tc->hpd_pin >= 0 && tc->bridge.dev) {
                /*
                 * H is triggered when the GPIO goes high.
                 *
                 * LC is triggered when the GPIO goes low and stays low for
                 * the duration of LCNT
                 */
                bool h = val & INT_GPIO_H(tc->hpd_pin);
                bool lc = val & INT_GPIO_LC(tc->hpd_pin);

                dev_dbg(tc->dev, "GPIO%d: %s %s\n", tc->hpd_pin,
                        h ? "H" : "", lc ? "LC" : "");

                if (h || lc)
                        drm_kms_helper_hotplug_event(tc->bridge.dev);
        }

        regmap_write(tc->regmap, INTSTS_G, val);

        return IRQ_HANDLED;
}

static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct drm_panel *panel;
        struct tc_data *tc;
        int ret;

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

        tc->dev = dev;

        /* port@2 is the output port */
        ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &panel, NULL);
        if (ret && ret != -ENODEV)
                return ret;

        if (panel) {
                struct drm_bridge *panel_bridge;

                panel_bridge = devm_drm_panel_bridge_add(dev, panel);
                if (IS_ERR(panel_bridge))
                        return PTR_ERR(panel_bridge);

                tc->panel_bridge = panel_bridge;
                tc->bridge.type = DRM_MODE_CONNECTOR_eDP;
        } else {
                tc->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
        }

        /* Shut down GPIO is optional */
        tc->sd_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
        if (IS_ERR(tc->sd_gpio))
                return PTR_ERR(tc->sd_gpio);

        if (tc->sd_gpio) {
                gpiod_set_value_cansleep(tc->sd_gpio, 0);
                usleep_range(5000, 10000);
        }

        /* Reset GPIO is optional */
        tc->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(tc->reset_gpio))
                return PTR_ERR(tc->reset_gpio);

        if (tc->reset_gpio) {
                gpiod_set_value_cansleep(tc->reset_gpio, 1);
                usleep_range(5000, 10000);
        }

        tc->refclk = devm_clk_get(dev, "ref");
        if (IS_ERR(tc->refclk)) {
                ret = PTR_ERR(tc->refclk);
                dev_err(dev, "Failed to get refclk: %d\n", ret);
                return ret;
        }

        tc->regmap = devm_regmap_init_i2c(client, &tc_regmap_config);
        if (IS_ERR(tc->regmap)) {
                ret = PTR_ERR(tc->regmap);
                dev_err(dev, "Failed to initialize regmap: %d\n", ret);
                return ret;
        }

        ret = of_property_read_u32(dev->of_node, "toshiba,hpd-pin",
                                   &tc->hpd_pin);
        if (ret) {
                tc->hpd_pin = -ENODEV;
        } else {
                if (tc->hpd_pin < 0 || tc->hpd_pin > 1) {
                        dev_err(dev, "failed to parse HPD number\n");
                        return ret;
                }
        }

        if (client->irq > 0) {
                /* enable SysErr */
                regmap_write(tc->regmap, INTCTL_G, INT_SYSERR);

                ret = devm_request_threaded_irq(dev, client->irq,
                                                NULL, tc_irq_handler,
                                                IRQF_ONESHOT,
                                                "tc358767-irq", tc);
                if (ret) {
                        dev_err(dev, "failed to register dp interrupt\n");
                        return ret;
                }

                tc->have_irq = true;
        }

        ret = regmap_read(tc->regmap, TC_IDREG, &tc->rev);
        if (ret) {
                dev_err(tc->dev, "can not read device ID: %d\n", ret);
                return ret;
        }

        if ((tc->rev != 0x6601) && (tc->rev != 0x6603)) {
                dev_err(tc->dev, "invalid device ID: 0x%08x\n", tc->rev);
                return -EINVAL;
        }

        tc->assr = (tc->rev == 0x6601); /* Enable ASSR for eDP panels */

        if (!tc->reset_gpio) {
                /*
                 * If the reset pin isn't present, do a software reset. It isn't
                 * as thorough as the hardware reset, as we can't reset the I2C
                 * communication block for obvious reasons, but it's getting the
                 * chip into a defined state.
                 */
                regmap_update_bits(tc->regmap, SYSRSTENB,
                                ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP,
                                0);
                regmap_update_bits(tc->regmap, SYSRSTENB,
                                ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP,
                                ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP);
                usleep_range(5000, 10000);
        }

        if (tc->hpd_pin >= 0) {
                u32 lcnt_reg = tc->hpd_pin == 0 ? INT_GP0_LCNT : INT_GP1_LCNT;
                u32 h_lc = INT_GPIO_H(tc->hpd_pin) | INT_GPIO_LC(tc->hpd_pin);

                /* Set LCNT to 2ms */
                regmap_write(tc->regmap, lcnt_reg,
                             clk_get_rate(tc->refclk) * 2 / 1000);
                /* We need the "alternate" mode for HPD */
                regmap_write(tc->regmap, GPIOM, BIT(tc->hpd_pin));

                if (tc->have_irq) {
                        /* enable H & LC */
                        regmap_update_bits(tc->regmap, INTCTL_G, h_lc, h_lc);
                }
        }

        ret = tc_aux_link_setup(tc);
        if (ret)
                return ret;

        /* Register DP AUX channel */
        tc->aux.name = "TC358767 AUX i2c adapter";
        tc->aux.dev = tc->dev;
        tc->aux.transfer = tc_aux_transfer;
        drm_dp_aux_init(&tc->aux);

        tc->bridge.funcs = &tc_bridge_funcs;
        if (tc->hpd_pin >= 0)
                tc->bridge.ops |= DRM_BRIDGE_OP_DETECT;
        tc->bridge.ops |= DRM_BRIDGE_OP_EDID;

        tc->bridge.of_node = dev->of_node;
        drm_bridge_add(&tc->bridge);

        i2c_set_clientdata(client, tc);

        return 0;
}

static int tc_remove(struct i2c_client *client)
{
        struct tc_data *tc = i2c_get_clientdata(client);

        drm_bridge_remove(&tc->bridge);

        return 0;
}

static const struct i2c_device_id tc358767_i2c_ids[] = {
        { "tc358767", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, tc358767_i2c_ids);

static const struct of_device_id tc358767_of_ids[] = {
        { .compatible = "toshiba,tc358767", },
        { }
};
MODULE_DEVICE_TABLE(of, tc358767_of_ids);

static struct i2c_driver tc358767_driver = {
        .driver = {
                .name = "tc358767",
                .of_match_table = tc358767_of_ids,
        },
        .id_table = tc358767_i2c_ids,
        .probe = tc_probe,
        .remove = tc_remove,
};
module_i2c_driver(tc358767_driver);

MODULE_AUTHOR("Andrey Gusakov <andrey.gusakov@cogentembedded.com>");
MODULE_DESCRIPTION("tc358767 eDP encoder driver");
MODULE_LICENSE("GPL");