path: root/drivers/gpu/drm/bridge/tc358775.c

// SPDX-License-Identifier: GPL-2.0
/*
 * TC358775 DSI to LVDS bridge driver
 *
 * Copyright (C) 2020 SMART Wireless Computing
 * Author: Vinay Simha BN <simhavcs@gmail.com>
 *
 */
/* #define DEBUG */
#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/media-bus-format.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#include <asm/unaligned.h>

#include <drm/display/drm_dp_helper.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drm_probe_helper.h>

#define FLD_VAL(val, start, end) FIELD_PREP(GENMASK(start, end), val)

/* Registers */

/* DSI D-PHY Layer Registers */
#define D0W_DPHYCONTTX  0x0004  /* Data Lane 0 DPHY Tx Control */
#define CLW_DPHYCONTRX  0x0020  /* Clock Lane DPHY Rx Control */
#define D0W_DPHYCONTRX  0x0024  /* Data Lane 0 DPHY Rx Control */
#define D1W_DPHYCONTRX  0x0028  /* Data Lane 1 DPHY Rx Control */
#define D2W_DPHYCONTRX  0x002C  /* Data Lane 2 DPHY Rx Control */
#define D3W_DPHYCONTRX  0x0030  /* Data Lane 3 DPHY Rx Control */
#define COM_DPHYCONTRX  0x0038  /* DPHY Rx Common Control */
#define CLW_CNTRL       0x0040  /* Clock Lane Control */
#define D0W_CNTRL       0x0044  /* Data Lane 0 Control */
#define D1W_CNTRL       0x0048  /* Data Lane 1 Control */
#define D2W_CNTRL       0x004C  /* Data Lane 2 Control */
#define D3W_CNTRL       0x0050  /* Data Lane 3 Control */
#define DFTMODE_CNTRL   0x0054  /* DFT Mode Control */

/* DSI PPI Layer Registers */
#define PPI_STARTPPI    0x0104  /* START control bit of PPI-TX function. */
#define PPI_START_FUNCTION      1

#define PPI_BUSYPPI     0x0108
#define PPI_LINEINITCNT 0x0110  /* Line Initialization Wait Counter  */
#define PPI_LPTXTIMECNT 0x0114
#define PPI_LANEENABLE  0x0134  /* Enables each lane at the PPI layer. */
#define PPI_TX_RX_TA    0x013C  /* DSI Bus Turn Around timing parameters */

/* Analog timer function enable */
#define PPI_CLS_ATMR    0x0140  /* Delay for Clock Lane in LPRX  */
#define PPI_D0S_ATMR    0x0144  /* Delay for Data Lane 0 in LPRX */
#define PPI_D1S_ATMR    0x0148  /* Delay for Data Lane 1 in LPRX */
#define PPI_D2S_ATMR    0x014C  /* Delay for Data Lane 2 in LPRX */
#define PPI_D3S_ATMR    0x0150  /* Delay for Data Lane 3 in LPRX */

#define PPI_D0S_CLRSIPOCOUNT    0x0164  /* For lane 0 */
#define PPI_D1S_CLRSIPOCOUNT    0x0168  /* For lane 1 */
#define PPI_D2S_CLRSIPOCOUNT    0x016C  /* For lane 2 */
#define PPI_D3S_CLRSIPOCOUNT    0x0170  /* For lane 3 */

#define CLS_PRE         0x0180  /* Digital Counter inside of PHY IO */
#define D0S_PRE         0x0184  /* Digital Counter inside of PHY IO */
#define D1S_PRE         0x0188  /* Digital Counter inside of PHY IO */
#define D2S_PRE         0x018C  /* Digital Counter inside of PHY IO */
#define D3S_PRE         0x0190  /* Digital Counter inside of PHY IO */
#define CLS_PREP        0x01A0  /* Digital Counter inside of PHY IO */
#define D0S_PREP        0x01A4  /* Digital Counter inside of PHY IO */
#define D1S_PREP        0x01A8  /* Digital Counter inside of PHY IO */
#define D2S_PREP        0x01AC  /* Digital Counter inside of PHY IO */
#define D3S_PREP        0x01B0  /* Digital Counter inside of PHY IO */
#define CLS_ZERO        0x01C0  /* Digital Counter inside of PHY IO */
#define D0S_ZERO        0x01C4  /* Digital Counter inside of PHY IO */
#define D1S_ZERO        0x01C8  /* Digital Counter inside of PHY IO */
#define D2S_ZERO        0x01CC  /* Digital Counter inside of PHY IO */
#define D3S_ZERO        0x01D0  /* Digital Counter inside of PHY IO */

#define PPI_CLRFLG      0x01E0  /* PRE Counters has reached set values */
#define PPI_CLRSIPO     0x01E4  /* Clear SIPO values, Slave mode use only. */
#define HSTIMEOUT       0x01F0  /* HS Rx Time Out Counter */
#define HSTIMEOUTENABLE 0x01F4  /* Enable HS Rx Time Out Counter */
#define DSI_STARTDSI    0x0204  /* START control bit of DSI-TX function */
#define DSI_RX_START	1

#define DSI_BUSYDSI     0x0208
#define DSI_LANEENABLE  0x0210  /* Enables each lane at the Protocol layer. */
#define DSI_LANESTATUS0 0x0214  /* Displays lane is in HS RX mode. */
#define DSI_LANESTATUS1 0x0218  /* Displays lane is in ULPS or STOP state */

#define DSI_INTSTATUS   0x0220  /* Interrupt Status */
#define DSI_INTMASK     0x0224  /* Interrupt Mask */
#define DSI_INTCLR      0x0228  /* Interrupt Clear */
#define DSI_LPTXTO      0x0230  /* Low Power Tx Time Out Counter */

#define DSIERRCNT       0x0300  /* DSI Error Count */
#define APLCTRL         0x0400  /* Application Layer Control */
#define RDPKTLN         0x0404  /* Command Read Packet Length */

#define VPCTRL          0x0450  /* Video Path Control */
#define HTIM1           0x0454  /* Horizontal Timing Control 1 */
#define HTIM2           0x0458  /* Horizontal Timing Control 2 */
#define VTIM1           0x045C  /* Vertical Timing Control 1 */
#define VTIM2           0x0460  /* Vertical Timing Control 2 */
#define VFUEN           0x0464  /* Video Frame Timing Update Enable */
#define VFUEN_EN	BIT(0)  /* Upload Enable */

/* Mux Input Select for LVDS LINK Input */
#define LV_MX0003        0x0480  /* Bit 0 to 3 */
#define LV_MX0407        0x0484  /* Bit 4 to 7 */
#define LV_MX0811        0x0488  /* Bit 8 to 11 */
#define LV_MX1215        0x048C  /* Bit 12 to 15 */
#define LV_MX1619        0x0490  /* Bit 16 to 19 */
#define LV_MX2023        0x0494  /* Bit 20 to 23 */
#define LV_MX2427        0x0498  /* Bit 24 to 27 */
#define LV_MX(b0, b1, b2, b3)	(FLD_VAL(b0, 4, 0) | FLD_VAL(b1, 12, 8) | \
				FLD_VAL(b2, 20, 16) | FLD_VAL(b3, 28, 24))

/* Input bit numbers used in mux registers */
enum {
	LVI_R0,
	LVI_R1,
	LVI_R2,
	LVI_R3,
	LVI_R4,
	LVI_R5,
	LVI_R6,
	LVI_R7,
	LVI_G0,
	LVI_G1,
	LVI_G2,
	LVI_G3,
	LVI_G4,
	LVI_G5,
	LVI_G6,
	LVI_G7,
	LVI_B0,
	LVI_B1,
	LVI_B2,
	LVI_B3,
	LVI_B4,
	LVI_B5,
	LVI_B6,
	LVI_B7,
	LVI_HS,
	LVI_VS,
	LVI_DE,
	LVI_L0
};

#define LVCFG           0x049C  /* LVDS Configuration  */
#define LVPHY0          0x04A0  /* LVDS PHY 0 */
#define LV_PHY0_RST(v)          FLD_VAL(v, 22, 22) /* PHY reset */
#define LV_PHY0_IS(v)           FLD_VAL(v, 15, 14)
#define LV_PHY0_ND(v)           FLD_VAL(v, 4, 0) /* Frequency range select */
#define LV_PHY0_PRBS_ON(v)      FLD_VAL(v, 20, 16) /* Clock/Data Flag pins */

#define LVPHY1          0x04A4  /* LVDS PHY 1 */
#define SYSSTAT         0x0500  /* System Status  */
#define SYSRST          0x0504  /* System Reset  */

#define SYS_RST_I2CS	BIT(0) /* Reset I2C-Slave controller */
#define SYS_RST_I2CM	BIT(1) /* Reset I2C-Master controller */
#define SYS_RST_LCD	BIT(2) /* Reset LCD controller */
#define SYS_RST_BM	BIT(3) /* Reset Bus Management controller */
#define SYS_RST_DSIRX	BIT(4) /* Reset DSI-RX and App controller */
#define SYS_RST_REG	BIT(5) /* Reset Register module */

/* GPIO Registers */
#define GPIOC           0x0520  /* GPIO Control  */
#define GPIOO           0x0524  /* GPIO Output  */
#define GPIOI           0x0528  /* GPIO Input  */

/* I2C Registers */
#define I2CTIMCTRL      0x0540  /* I2C IF Timing and Enable Control */
#define I2CMADDR        0x0544  /* I2C Master Addressing */
#define WDATAQ          0x0548  /* Write Data Queue */
#define RDATAQ          0x054C  /* Read Data Queue */

/* Chip ID and Revision ID Register */
#define IDREG           0x0580

#define LPX_PERIOD		4
#define TTA_GET			0x40000
#define TTA_SURE		6
#define SINGLE_LINK		1
#define DUAL_LINK		2

#define TC358775XBG_ID  0x00007500

/* Debug Registers */
#define DEBUG00         0x05A0  /* Debug */
#define DEBUG01         0x05A4  /* LVDS Data */

#define DSI_CLEN_BIT		BIT(0)
#define DIVIDE_BY_3		3 /* PCLK=DCLK/3 */
#define DIVIDE_BY_6		6 /* PCLK=DCLK/6 */
#define LVCFG_LVEN_BIT		BIT(0)

#define L0EN BIT(1)

#define TC358775_VPCTRL_VSDELAY__MASK	0x3FF00000
#define TC358775_VPCTRL_VSDELAY__SHIFT	20
static inline u32 TC358775_VPCTRL_VSDELAY(uint32_t val)
{
	return ((val) << TC358775_VPCTRL_VSDELAY__SHIFT) &
			TC358775_VPCTRL_VSDELAY__MASK;
}

#define TC358775_VPCTRL_OPXLFMT__MASK	0x00000100
#define TC358775_VPCTRL_OPXLFMT__SHIFT	8
static inline u32 TC358775_VPCTRL_OPXLFMT(uint32_t val)
{
	return ((val) << TC358775_VPCTRL_OPXLFMT__SHIFT) &
			TC358775_VPCTRL_OPXLFMT__MASK;
}

#define TC358775_VPCTRL_MSF__MASK	0x00000001
#define TC358775_VPCTRL_MSF__SHIFT	0
static inline u32 TC358775_VPCTRL_MSF(uint32_t val)
{
	return ((val) << TC358775_VPCTRL_MSF__SHIFT) &
			TC358775_VPCTRL_MSF__MASK;
}

#define TC358775_LVCFG_PCLKDIV__MASK	0x000000f0
#define TC358775_LVCFG_PCLKDIV__SHIFT	4
static inline u32 TC358775_LVCFG_PCLKDIV(uint32_t val)
{
	return ((val) << TC358775_LVCFG_PCLKDIV__SHIFT) &
			TC358775_LVCFG_PCLKDIV__MASK;
}

#define TC358775_LVCFG_LVDLINK__MASK                         0x00000002
#define TC358775_LVCFG_LVDLINK__SHIFT                        1
static inline u32 TC358775_LVCFG_LVDLINK(uint32_t val)
{
	return ((val) << TC358775_LVCFG_LVDLINK__SHIFT) &
			TC358775_LVCFG_LVDLINK__MASK;
}

enum tc358775_ports {
	TC358775_DSI_IN,
	TC358775_LVDS_OUT0,
	TC358775_LVDS_OUT1,
};

struct tc_data {
	struct i2c_client	*i2c;
	struct device		*dev;

	struct drm_bridge	bridge;
	struct drm_bridge	*panel_bridge;

	struct device_node *host_node;
	struct mipi_dsi_device *dsi;
	u8 num_dsi_lanes;

	struct regulator	*vdd;
	struct regulator	*vddio;
	struct gpio_desc	*reset_gpio;
	struct gpio_desc	*stby_gpio;
	u8			lvds_link; /* single-link or dual-link */
	u8			bpc;
};

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

static void tc_bridge_pre_enable(struct drm_bridge *bridge)
{
	struct tc_data *tc = bridge_to_tc(bridge);
	struct device *dev = &tc->dsi->dev;
	int ret;

	ret = regulator_enable(tc->vddio);
	if (ret < 0)
		dev_err(dev, "regulator vddio enable failed, %d\n", ret);
	usleep_range(10000, 11000);

	ret = regulator_enable(tc->vdd);
	if (ret < 0)
		dev_err(dev, "regulator vdd enable failed, %d\n", ret);
	usleep_range(10000, 11000);

	gpiod_set_value(tc->stby_gpio, 0);
	usleep_range(10000, 11000);

	gpiod_set_value(tc->reset_gpio, 0);
	usleep_range(10, 20);
}

static void tc_bridge_post_disable(struct drm_bridge *bridge)
{
	struct tc_data *tc = bridge_to_tc(bridge);
	struct device *dev = &tc->dsi->dev;
	int ret;

	gpiod_set_value(tc->reset_gpio, 1);
	usleep_range(10, 20);

	gpiod_set_value(tc->stby_gpio, 1);
	usleep_range(10000, 11000);

	ret = regulator_disable(tc->vdd);
	if (ret < 0)
		dev_err(dev, "regulator vdd disable failed, %d\n", ret);
	usleep_range(10000, 11000);

	ret = regulator_disable(tc->vddio);
	if (ret < 0)
		dev_err(dev, "regulator vddio disable failed, %d\n", ret);
	usleep_range(10000, 11000);
}

static void d2l_read(struct i2c_client *i2c, u16 addr, u32 *val)
{
	int ret;
	u8 buf_addr[2];

	put_unaligned_be16(addr, buf_addr);
	ret = i2c_master_send(i2c, buf_addr, sizeof(buf_addr));
	if (ret < 0)
		goto fail;

	ret = i2c_master_recv(i2c, (u8 *)val, sizeof(*val));
	if (ret < 0)
		goto fail;

	pr_debug("d2l: I2C : addr:%04x value:%08x\n", addr, *val);
	return;

fail:
	dev_err(&i2c->dev, "Error %d reading from subaddress 0x%x\n",
		ret, addr);
}

static void d2l_write(struct i2c_client *i2c, u16 addr, u32 val)
{
	u8 data[6];
	int ret;

	put_unaligned_be16(addr, data);
	put_unaligned_le32(val, data + 2);

	ret = i2c_master_send(i2c, data, ARRAY_SIZE(data));
	if (ret < 0)
		dev_err(&i2c->dev, "Error %d writing to subaddress 0x%x\n",
			ret, addr);
}

/* helper function to access bus_formats */
static struct drm_connector *get_connector(struct drm_encoder *encoder)
{
	struct drm_device *dev = encoder->dev;
	struct drm_connector *connector;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
		if (connector->encoder == encoder)
			return connector;

	return NULL;
}

static void tc_bridge_enable(struct drm_bridge *bridge)
{
	struct tc_data *tc = bridge_to_tc(bridge);
	u32 hback_porch, hsync_len, hfront_porch, hactive, htime1, htime2;
	u32 vback_porch, vsync_len, vfront_porch, vactive, vtime1, vtime2;
	u32 val = 0;
	u16 dsiclk, clkdiv, byteclk, t1, t2, t3, vsdelay;
	struct drm_display_mode *mode;
	struct drm_connector *connector = get_connector(bridge->encoder);

	mode = &bridge->encoder->crtc->state->adjusted_mode;

	hback_porch = mode->htotal - mode->hsync_end;
	hsync_len  = mode->hsync_end - mode->hsync_start;
	vback_porch = mode->vtotal - mode->vsync_end;
	vsync_len  = mode->vsync_end - mode->vsync_start;

	htime1 = (hback_porch << 16) + hsync_len;
	vtime1 = (vback_porch << 16) + vsync_len;

	hfront_porch = mode->hsync_start - mode->hdisplay;
	hactive = mode->hdisplay;
	vfront_porch = mode->vsync_start - mode->vdisplay;
	vactive = mode->vdisplay;

	htime2 = (hfront_porch << 16) + hactive;
	vtime2 = (vfront_porch << 16) + vactive;

	d2l_read(tc->i2c, IDREG, &val);

	dev_info(tc->dev, "DSI2LVDS Chip ID.%02x Revision ID. %02x **\n",
		 (val >> 8) & 0xFF, val & 0xFF);

	d2l_write(tc->i2c, SYSRST, SYS_RST_REG | SYS_RST_DSIRX | SYS_RST_BM |
		  SYS_RST_LCD | SYS_RST_I2CM | SYS_RST_I2CS);
	usleep_range(30000, 40000);

	d2l_write(tc->i2c, PPI_TX_RX_TA, TTA_GET | TTA_SURE);
	d2l_write(tc->i2c, PPI_LPTXTIMECNT, LPX_PERIOD);
	d2l_write(tc->i2c, PPI_D0S_CLRSIPOCOUNT, 3);
	d2l_write(tc->i2c, PPI_D1S_CLRSIPOCOUNT, 3);
	d2l_write(tc->i2c, PPI_D2S_CLRSIPOCOUNT, 3);
	d2l_write(tc->i2c, PPI_D3S_CLRSIPOCOUNT, 3);

	val = ((L0EN << tc->num_dsi_lanes) - L0EN) | DSI_CLEN_BIT;
	d2l_write(tc->i2c, PPI_LANEENABLE, val);
	d2l_write(tc->i2c, DSI_LANEENABLE, val);

	d2l_write(tc->i2c, PPI_STARTPPI, PPI_START_FUNCTION);
	d2l_write(tc->i2c, DSI_STARTDSI, DSI_RX_START);

	if (tc->bpc == 8)
		val = TC358775_VPCTRL_OPXLFMT(1);
	else /* bpc = 6; */
		val = TC358775_VPCTRL_MSF(1);

	dsiclk = mode->crtc_clock * 3 * tc->bpc / tc->num_dsi_lanes / 1000;
	clkdiv = dsiclk / (tc->lvds_link == DUAL_LINK ? DIVIDE_BY_6 : DIVIDE_BY_3);
	byteclk = dsiclk / 4;
	t1 = hactive * (tc->bpc * 3 / 8) / tc->num_dsi_lanes;
	t2 = ((100000 / clkdiv)) * (hactive + hback_porch + hsync_len + hfront_porch) / 1000;
	t3 = ((t2 * byteclk) / 100) - (hactive * (tc->bpc * 3 / 8) /
		tc->num_dsi_lanes);

	vsdelay = (clkdiv * (t1 + t3) / byteclk) - hback_porch - hsync_len - hactive;

	val |= TC358775_VPCTRL_VSDELAY(vsdelay);
	d2l_write(tc->i2c, VPCTRL, val);

	d2l_write(tc->i2c, HTIM1, htime1);
	d2l_write(tc->i2c, VTIM1, vtime1);
	d2l_write(tc->i2c, HTIM2, htime2);
	d2l_write(tc->i2c, VTIM2, vtime2);

	d2l_write(tc->i2c, VFUEN, VFUEN_EN);
	d2l_write(tc->i2c, SYSRST, SYS_RST_LCD);
	d2l_write(tc->i2c, LVPHY0, LV_PHY0_PRBS_ON(4) | LV_PHY0_ND(6));

	dev_dbg(tc->dev, "bus_formats %04x bpc %d\n",
		connector->display_info.bus_formats[0],
		tc->bpc);
	/*
	 * Default hardware register settings of tc358775 configured
	 * with MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA jeida-24 format
	 */
	if (connector->display_info.bus_formats[0] ==
		MEDIA_BUS_FMT_RGB888_1X7X4_SPWG) {
		/* VESA-24 */
		d2l_write(tc->i2c, LV_MX0003, LV_MX(LVI_R0, LVI_R1, LVI_R2, LVI_R3));
		d2l_write(tc->i2c, LV_MX0407, LV_MX(LVI_R4, LVI_R7, LVI_R5, LVI_G0));
		d2l_write(tc->i2c, LV_MX0811, LV_MX(LVI_G1, LVI_G2, LVI_G6, LVI_G7));
		d2l_write(tc->i2c, LV_MX1215, LV_MX(LVI_G3, LVI_G4, LVI_G5, LVI_B0));
		d2l_write(tc->i2c, LV_MX1619, LV_MX(LVI_B6, LVI_B7, LVI_B1, LVI_B2));
		d2l_write(tc->i2c, LV_MX2023, LV_MX(LVI_B3, LVI_B4, LVI_B5, LVI_L0));
		d2l_write(tc->i2c, LV_MX2427, LV_MX(LVI_HS, LVI_VS, LVI_DE, LVI_R6));
	} else { /*  MEDIA_BUS_FMT_RGB666_1X7X3_SPWG - JEIDA-18 */
		d2l_write(tc->i2c, LV_MX0003, LV_MX(LVI_R0, LVI_R1, LVI_R2, LVI_R3));
		d2l_write(tc->i2c, LV_MX0407, LV_MX(LVI_R4, LVI_L0, LVI_R5, LVI_G0));
		d2l_write(tc->i2c, LV_MX0811, LV_MX(LVI_G1, LVI_G2, LVI_L0, LVI_L0));
		d2l_write(tc->i2c, LV_MX1215, LV_MX(LVI_G3, LVI_G4, LVI_G5, LVI_B0));
		d2l_write(tc->i2c, LV_MX1619, LV_MX(LVI_L0, LVI_L0, LVI_B1, LVI_B2));
		d2l_write(tc->i2c, LV_MX2023, LV_MX(LVI_B3, LVI_B4, LVI_B5, LVI_L0));
		d2l_write(tc->i2c, LV_MX2427, LV_MX(LVI_HS, LVI_VS, LVI_DE, LVI_L0));
	}

	d2l_write(tc->i2c, VFUEN, VFUEN_EN);

	val = LVCFG_LVEN_BIT;
	if (tc->lvds_link == DUAL_LINK) {
		val |= TC358775_LVCFG_LVDLINK(1);
		val |= TC358775_LVCFG_PCLKDIV(DIVIDE_BY_6);
	} else {
		val |= TC358775_LVCFG_PCLKDIV(DIVIDE_BY_3);
	}
	d2l_write(tc->i2c, LVCFG, val);
}

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);

	/*
	 * Maximum pixel clock speed 135MHz for single-link
	 * 270MHz for dual-link
	 */
	if ((mode->clock > 135000 && tc->lvds_link == SINGLE_LINK) ||
	    (mode->clock > 270000 && tc->lvds_link == DUAL_LINK))
		return MODE_CLOCK_HIGH;

	switch (info->bus_formats[0]) {
	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
		/* RGB888 */
		tc->bpc = 8;
		break;
	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
		/* RGB666 */
		tc->bpc = 6;
		break;
	default:
		dev_warn(tc->dev,
			 "unsupported LVDS bus format 0x%04x\n",
			 info->bus_formats[0]);
		return MODE_NOMODE;
	}

	return MODE_OK;
}

static int tc358775_parse_dt(struct device_node *np, struct tc_data *tc)
{
	struct device_node *endpoint;
	struct device_node *parent;
	struct device_node *remote;
	int dsi_lanes = -1;

	/*
	 * To get the data-lanes of dsi, we need to access the dsi0_out of port1
	 *  of dsi0 endpoint from bridge port0 of d2l_in
	 */
	endpoint = of_graph_get_endpoint_by_regs(tc->dev->of_node,
						 TC358775_DSI_IN, -1);
	if (endpoint) {
		/* dsi0_out node */
		parent = of_graph_get_remote_port_parent(endpoint);
		of_node_put(endpoint);
		if (parent) {
			/* dsi0 port 1 */
			dsi_lanes = drm_of_get_data_lanes_count_ep(parent, 1, -1, 1, 4);
			of_node_put(parent);
		}
	}

	if (dsi_lanes < 0)
		return dsi_lanes;

	tc->num_dsi_lanes = dsi_lanes;

	tc->host_node = of_graph_get_remote_node(np, 0, 0);
	if (!tc->host_node)
		return -ENODEV;

	of_node_put(tc->host_node);

	tc->lvds_link = SINGLE_LINK;
	endpoint = of_graph_get_endpoint_by_regs(tc->dev->of_node,
						 TC358775_LVDS_OUT1, -1);
	if (endpoint) {
		remote = of_graph_get_remote_port_parent(endpoint);
		of_node_put(endpoint);

		if (remote) {
			if (of_device_is_available(remote))
				tc->lvds_link = DUAL_LINK;
			of_node_put(remote);
		}
	}

	dev_dbg(tc->dev, "no.of dsi lanes: %d\n", tc->num_dsi_lanes);
	dev_dbg(tc->dev, "operating in %d-link mode\n",	tc->lvds_link);

	return 0;
}

static int tc_bridge_attach(struct drm_bridge *bridge,
			    enum drm_bridge_attach_flags flags)
{
	struct tc_data *tc = bridge_to_tc(bridge);

	/* Attach the panel-bridge to the dsi bridge */
	return drm_bridge_attach(bridge->encoder, tc->panel_bridge,
				 &tc->bridge, flags);
}

static const struct drm_bridge_funcs tc_bridge_funcs = {
	.attach = tc_bridge_attach,
	.pre_enable = tc_bridge_pre_enable,
	.enable = tc_bridge_enable,
	.mode_valid = tc_mode_valid,
	.post_disable = tc_bridge_post_disable,
};

static int tc_attach_host(struct tc_data *tc)
{
	struct device *dev = &tc->i2c->dev;
	struct mipi_dsi_host *host;
	struct mipi_dsi_device *dsi;
	int ret;
	const struct mipi_dsi_device_info info = { .type = "tc358775",
							.channel = 0,
							.node = NULL,
						};

	host = of_find_mipi_dsi_host_by_node(tc->host_node);
	if (!host) {
		dev_err(dev, "failed to find dsi host\n");
		return -EPROBE_DEFER;
	}

	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
	if (IS_ERR(dsi)) {
		dev_err(dev, "failed to create dsi device\n");
		return PTR_ERR(dsi);
	}

	tc->dsi = dsi;

	dsi->lanes = tc->num_dsi_lanes;
	dsi->format = MIPI_DSI_FMT_RGB888;
	dsi->mode_flags = MIPI_DSI_MODE_VIDEO;

	ret = devm_mipi_dsi_attach(dev, dsi);
	if (ret < 0) {
		dev_err(dev, "failed to attach dsi to host\n");
		return ret;
	}

	return 0;
}

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

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

	tc->dev = dev;
	tc->i2c = client;

	tc->panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node,
						  TC358775_LVDS_OUT0, 0);
	if (IS_ERR(tc->panel_bridge))
		return PTR_ERR(tc->panel_bridge);

	ret = tc358775_parse_dt(dev->of_node, tc);
	if (ret)
		return ret;

	tc->vddio = devm_regulator_get(dev, "vddio-supply");
	if (IS_ERR(tc->vddio)) {
		ret = PTR_ERR(tc->vddio);
		dev_err(dev, "vddio-supply not found\n");
		return ret;
	}

	tc->vdd = devm_regulator_get(dev, "vdd-supply");
	if (IS_ERR(tc->vdd)) {
		ret = PTR_ERR(tc->vdd);
		dev_err(dev, "vdd-supply not found\n");
		return ret;
	}

	tc->stby_gpio = devm_gpiod_get(dev, "stby", GPIOD_OUT_HIGH);
	if (IS_ERR(tc->stby_gpio)) {
		ret = PTR_ERR(tc->stby_gpio);
		dev_err(dev, "cannot get stby-gpio %d\n", ret);
		return ret;
	}

	tc->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(tc->reset_gpio)) {
		ret = PTR_ERR(tc->reset_gpio);
		dev_err(dev, "cannot get reset-gpios %d\n", ret);
		return ret;
	}

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

	i2c_set_clientdata(client, tc);

	ret = tc_attach_host(tc);
	if (ret)
		goto err_bridge_remove;

	return 0;

err_bridge_remove:
	drm_bridge_remove(&tc->bridge);
	return ret;
}

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

	drm_bridge_remove(&tc->bridge);
}

static const struct i2c_device_id tc358775_i2c_ids[] = {
	{ "tc358775", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tc358775_i2c_ids);

static const struct of_device_id tc358775_of_ids[] = {
	{ .compatible = "toshiba,tc358775", },
	{ }
};
MODULE_DEVICE_TABLE(of, tc358775_of_ids);

static struct i2c_driver tc358775_driver = {
	.driver = {
		.name = "tc358775",
		.of_match_table = tc358775_of_ids,
	},
	.id_table = tc358775_i2c_ids,
	.probe = tc_probe,
	.remove	= tc_remove,
};
module_i2c_driver(tc358775_driver);

MODULE_AUTHOR("Vinay Simha BN <simhavcs@gmail.com>");
MODULE_DESCRIPTION("TC358775 DSI/LVDS bridge driver");
MODULE_LICENSE("GPL v2");