drivers/gpu/drm/panel/panel-sitronix-st7701.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2019, Amarula Solutions.
  * Author: Jagan Teki <jagan@amarulasolutions.com>
  */

 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_print.h>

 #include <linux/backlight.h>
 #include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regulator/consumer.h>

 #include <video/mipi_display.h>

 /* Command2 BKx selection command */
 #define DSI_CMD2BKX_SEL			0xFF

 /* Command2, BK0 commands */
 #define DSI_CMD2_BK0_PVGAMCTRL		0xB0 /* Positive Voltage Gamma Control */
 #define DSI_CMD2_BK0_NVGAMCTRL		0xB1 /* Negative Voltage Gamma Control */
 #define DSI_CMD2_BK0_LNESET		0xC0 /* Display Line setting */
 #define DSI_CMD2_BK0_PORCTRL		0xC1 /* Porch control */
 #define DSI_CMD2_BK0_INVSEL		0xC2 /* Inversion selection, Frame Rate Control */

 /* Command2, BK1 commands */
 #define DSI_CMD2_BK1_VRHS		0xB0 /* Vop amplitude setting */
 #define DSI_CMD2_BK1_VCOM		0xB1 /* VCOM amplitude setting */
 #define DSI_CMD2_BK1_VGHSS		0xB2 /* VGH Voltage setting */
 #define DSI_CMD2_BK1_TESTCMD		0xB3 /* TEST Command Setting */
 #define DSI_CMD2_BK1_VGLS		0xB5 /* VGL Voltage setting */
 #define DSI_CMD2_BK1_PWCTLR1		0xB7 /* Power Control 1 */
 #define DSI_CMD2_BK1_PWCTLR2		0xB8 /* Power Control 2 */
 #define DSI_CMD2_BK1_SPD1		0xC1 /* Source pre_drive timing set1 */
 #define DSI_CMD2_BK1_SPD2		0xC2 /* Source EQ2 Setting */
 #define DSI_CMD2_BK1_MIPISET1		0xD0 /* MIPI Setting 1 */

 /**
  * Command2 with BK function selection.
  *
  * BIT[4, 0]: [CN2, BKXSEL]
  * 10 = CMD2BK0, Command2 BK0
  * 11 = CMD2BK1, Command2 BK1
  * 00 = Command2 disable
  */
 #define DSI_CMD2BK1_SEL			0x11
 #define DSI_CMD2BK0_SEL			0x10
 #define DSI_CMD2BKX_SEL_NONE		0x00

 /* Command2, BK0 bytes */
 #define DSI_LINESET_LINE		0x69
 #define DSI_LINESET_LDE_EN		BIT(7)
 #define DSI_LINESET_LINEDELTA		GENMASK(1, 0)
 #define DSI_CMD2_BK0_LNESET_B1		DSI_LINESET_LINEDELTA
 #define DSI_CMD2_BK0_LNESET_B0		(DSI_LINESET_LDE_EN | DSI_LINESET_LINE)
 #define DSI_INVSEL_DEFAULT		GENMASK(5, 4)
 #define DSI_INVSEL_NLINV		GENMASK(2, 0)
 #define DSI_INVSEL_RTNI			GENMASK(2, 1)
 #define DSI_CMD2_BK0_INVSEL_B1		DSI_INVSEL_RTNI
 #define DSI_CMD2_BK0_INVSEL_B0		(DSI_INVSEL_DEFAULT | DSI_INVSEL_NLINV)
 #define DSI_CMD2_BK0_PORCTRL_B0(m)	((m)->vtotal - (m)->vsync_end)
 #define DSI_CMD2_BK0_PORCTRL_B1(m)	((m)->vsync_start - (m)->vdisplay)

 /* Command2, BK1 bytes */
 #define DSI_CMD2_BK1_VRHA_SET		0x45
 #define DSI_CMD2_BK1_VCOM_SET		0x13
 #define DSI_CMD2_BK1_VGHSS_SET		GENMASK(2, 0)
 #define DSI_CMD2_BK1_TESTCMD_VAL	BIT(7)
 #define DSI_VGLS_DEFAULT		BIT(6)
 #define DSI_VGLS_SEL			GENMASK(2, 0)
 #define DSI_CMD2_BK1_VGLS_SET		(DSI_VGLS_DEFAULT | DSI_VGLS_SEL)
 #define DSI_PWCTLR1_AP			BIT(7) /* Gamma OP bias, max */
 #define DSI_PWCTLR1_APIS		BIT(2) /* Source OP input bias, min */
 #define DSI_PWCTLR1_APOS		BIT(0) /* Source OP output bias, min */
 #define DSI_CMD2_BK1_PWCTLR1_SET	(DSI_PWCTLR1_AP | DSI_PWCTLR1_APIS | \
 					DSI_PWCTLR1_APOS)
 #define DSI_PWCTLR2_AVDD		BIT(5) /* AVDD 6.6v */
 #define DSI_PWCTLR2_AVCL		0x0    /* AVCL -4.4v */
 #define DSI_CMD2_BK1_PWCTLR2_SET	(DSI_PWCTLR2_AVDD | DSI_PWCTLR2_AVCL)
 #define DSI_SPD1_T2D			BIT(3)
 #define DSI_CMD2_BK1_SPD1_SET		(GENMASK(6, 4) | DSI_SPD1_T2D)
 #define DSI_CMD2_BK1_SPD2_SET		DSI_CMD2_BK1_SPD1_SET
 #define DSI_MIPISET1_EOT_EN		BIT(3)
 #define DSI_CMD2_BK1_MIPISET1_SET	(BIT(7) | DSI_MIPISET1_EOT_EN)

 struct st7701_panel_desc {
 	const struct drm_display_mode *mode;
 	unsigned int lanes;
 	unsigned long flags;
 	enum mipi_dsi_pixel_format format;
 	const char *const *supply_names;
 	unsigned int num_supplies;
 	unsigned int panel_sleep_delay;
 };

 struct st7701 {
 	struct drm_panel panel;
 	struct mipi_dsi_device *dsi;
 	const struct st7701_panel_desc *desc;

 	struct backlight_device *backlight;
 	struct regulator_bulk_data *supplies;
 	struct gpio_desc *reset;
 	unsigned int sleep_delay;
 };

 static inline struct st7701 *panel_to_st7701(struct drm_panel *panel)
 {
 	return container_of(panel, struct st7701, panel);
 }

 static inline int st7701_dsi_write(struct st7701 *st7701, const void *seq,
 				   size_t len)
 {
 	return mipi_dsi_dcs_write_buffer(st7701->dsi, seq, len);
 }

 #define ST7701_DSI(st7701, seq...)				\
 	{							\
 		const u8 d[] = { seq };				\
 		st7701_dsi_write(st7701, d, ARRAY_SIZE(d));	\
 	}

 static void st7701_init_sequence(struct st7701 *st7701)
 {
 	const struct drm_display_mode *mode = st7701->desc->mode;

 	ST7701_DSI(st7701, MIPI_DCS_SOFT_RESET, 0x00);

 	/* We need to wait 5ms before sending new commands */
 	msleep(5);

 	ST7701_DSI(st7701, MIPI_DCS_EXIT_SLEEP_MODE, 0x00);

 	msleep(st7701->sleep_delay);

 	/* Command2, BK0 */
 	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
 		   0x77, 0x01, 0x00, 0x00, DSI_CMD2BK0_SEL);
 	ST7701_DSI(st7701, DSI_CMD2_BK0_PVGAMCTRL, 0x00, 0x0E, 0x15, 0x0F,
 		   0x11, 0x08, 0x08, 0x08, 0x08, 0x23, 0x04, 0x13, 0x12,
 		   0x2B, 0x34, 0x1F);
 	ST7701_DSI(st7701, DSI_CMD2_BK0_NVGAMCTRL, 0x00, 0x0E, 0x95, 0x0F,
 		   0x13, 0x07, 0x09, 0x08, 0x08, 0x22, 0x04, 0x10, 0x0E,
 		   0x2C, 0x34, 0x1F);
 	ST7701_DSI(st7701, DSI_CMD2_BK0_LNESET,
 		   DSI_CMD2_BK0_LNESET_B0, DSI_CMD2_BK0_LNESET_B1);
 	ST7701_DSI(st7701, DSI_CMD2_BK0_PORCTRL,
 		   DSI_CMD2_BK0_PORCTRL_B0(mode),
 		   DSI_CMD2_BK0_PORCTRL_B1(mode));
 	ST7701_DSI(st7701, DSI_CMD2_BK0_INVSEL,
 		   DSI_CMD2_BK0_INVSEL_B0, DSI_CMD2_BK0_INVSEL_B1);

 	/* Command2, BK1 */
 	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
 			0x77, 0x01, 0x00, 0x00, DSI_CMD2BK1_SEL);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_VRHS, DSI_CMD2_BK1_VRHA_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_VCOM, DSI_CMD2_BK1_VCOM_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_VGHSS, DSI_CMD2_BK1_VGHSS_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_TESTCMD, DSI_CMD2_BK1_TESTCMD_VAL);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_VGLS, DSI_CMD2_BK1_VGLS_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_PWCTLR1, DSI_CMD2_BK1_PWCTLR1_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_PWCTLR2, DSI_CMD2_BK1_PWCTLR2_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_SPD1, DSI_CMD2_BK1_SPD1_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_SPD2, DSI_CMD2_BK1_SPD2_SET);
 	ST7701_DSI(st7701, DSI_CMD2_BK1_MIPISET1, DSI_CMD2_BK1_MIPISET1_SET);

 	/**
 	 * ST7701_SPEC_V1.2 is unable to provide enough information above this
 	 * specific command sequence, so grab the same from vendor BSP driver.
 	 */
 	ST7701_DSI(st7701, 0xE0, 0x00, 0x00, 0x02);
 	ST7701_DSI(st7701, 0xE1, 0x0B, 0x00, 0x0D, 0x00, 0x0C, 0x00, 0x0E,
 		   0x00, 0x00, 0x44, 0x44);
 	ST7701_DSI(st7701, 0xE2, 0x33, 0x33, 0x44, 0x44, 0x64, 0x00, 0x66,
 		   0x00, 0x65, 0x00, 0x67, 0x00, 0x00);
 	ST7701_DSI(st7701, 0xE3, 0x00, 0x00, 0x33, 0x33);
 	ST7701_DSI(st7701, 0xE4, 0x44, 0x44);
 	ST7701_DSI(st7701, 0xE5, 0x0C, 0x78, 0x3C, 0xA0, 0x0E, 0x78, 0x3C,
 		   0xA0, 0x10, 0x78, 0x3C, 0xA0, 0x12, 0x78, 0x3C, 0xA0);
 	ST7701_DSI(st7701, 0xE6, 0x00, 0x00, 0x33, 0x33);
 	ST7701_DSI(st7701, 0xE7, 0x44, 0x44);
 	ST7701_DSI(st7701, 0xE8, 0x0D, 0x78, 0x3C, 0xA0, 0x0F, 0x78, 0x3C,
 		   0xA0, 0x11, 0x78, 0x3C, 0xA0, 0x13, 0x78, 0x3C, 0xA0);
 	ST7701_DSI(st7701, 0xEB, 0x02, 0x02, 0x39, 0x39, 0xEE, 0x44, 0x00);
 	ST7701_DSI(st7701, 0xEC, 0x00, 0x00);
 	ST7701_DSI(st7701, 0xED, 0xFF, 0xF1, 0x04, 0x56, 0x72, 0x3F, 0xFF,
 		   0xFF, 0xFF, 0xFF, 0xF3, 0x27, 0x65, 0x40, 0x1F, 0xFF);

 	/* disable Command2 */
 	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
 		   0x77, 0x01, 0x00, 0x00, DSI_CMD2BKX_SEL_NONE);
 }

 static int st7701_prepare(struct drm_panel *panel)
 {
 	struct st7701 *st7701 = panel_to_st7701(panel);
 	int ret;

 	gpiod_set_value(st7701->reset, 0);

 	ret = regulator_bulk_enable(st7701->desc->num_supplies,
 				    st7701->supplies);
 	if (ret < 0)
 		return ret;
 	msleep(20);

 	gpiod_set_value(st7701->reset, 1);
 	msleep(150);

 	st7701_init_sequence(st7701);

 	return 0;
 }

 static int st7701_enable(struct drm_panel *panel)
 {
 	struct st7701 *st7701 = panel_to_st7701(panel);

 	ST7701_DSI(st7701, MIPI_DCS_SET_DISPLAY_ON, 0x00);
 	backlight_enable(st7701->backlight);

 	return 0;
 }

 static int st7701_disable(struct drm_panel *panel)
 {
 	struct st7701 *st7701 = panel_to_st7701(panel);

 	backlight_disable(st7701->backlight);
 	ST7701_DSI(st7701, MIPI_DCS_SET_DISPLAY_OFF, 0x00);

 	return 0;
 }

 static int st7701_unprepare(struct drm_panel *panel)
 {
 	struct st7701 *st7701 = panel_to_st7701(panel);

 	ST7701_DSI(st7701, MIPI_DCS_ENTER_SLEEP_MODE, 0x00);

 	msleep(st7701->sleep_delay);

 	gpiod_set_value(st7701->reset, 0);

 	/**
 	 * During the Resetting period, the display will be blanked
 	 * (The display is entering blanking sequence, which maximum
 	 * time is 120 ms, when Reset Starts in Sleep Out –mode. The
 	 * display remains the blank state in Sleep In –mode.) and
 	 * then return to Default condition for Hardware Reset.
 	 *
 	 * So we need wait sleep_delay time to make sure reset completed.
 	 */
 	msleep(st7701->sleep_delay);

 	regulator_bulk_disable(st7701->desc->num_supplies, st7701->supplies);

 	return 0;
 }

 static int st7701_get_modes(struct drm_panel *panel)
 {
 	struct st7701 *st7701 = panel_to_st7701(panel);
 	const struct drm_display_mode *desc_mode = st7701->desc->mode;
 	struct drm_display_mode *mode;

 	mode = drm_mode_duplicate(panel->drm, desc_mode);
 	if (!mode) {
 		DRM_DEV_ERROR(&st7701->dsi->dev,
 			      "failed to add mode %ux%ux@%u\n",
 			      desc_mode->hdisplay, desc_mode->vdisplay,
 			      desc_mode->vrefresh);
 		return -ENOMEM;
 	}

 	drm_mode_set_name(mode);
 	drm_mode_probed_add(panel->connector, mode);

 	panel->connector->display_info.width_mm = desc_mode->width_mm;
 	panel->connector->display_info.height_mm = desc_mode->height_mm;

 	return 1;
 }

 static const struct drm_panel_funcs st7701_funcs = {
 	.disable	= st7701_disable,
 	.unprepare	= st7701_unprepare,
 	.prepare	= st7701_prepare,
 	.enable		= st7701_enable,
 	.get_modes	= st7701_get_modes,
 };

 static const struct drm_display_mode ts8550b_mode = {
 	.clock		= 27500,

 	.hdisplay	= 480,
 	.hsync_start	= 480 + 38,
 	.hsync_end	= 480 + 38 + 12,
 	.htotal		= 480 + 38 + 12 + 12,

 	.vdisplay	= 854,
 	.vsync_start	= 854 + 4,
 	.vsync_end	= 854 + 4 + 8,
 	.vtotal		= 854 + 4 + 8 + 18,

 	.width_mm	= 69,
 	.height_mm	= 139,

 	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
 };

 static const char * const ts8550b_supply_names[] = {
 	"VCC",
 	"IOVCC",
 };

 static const struct st7701_panel_desc ts8550b_desc = {
 	.mode = &ts8550b_mode,
 	.lanes = 2,
 	.flags = MIPI_DSI_MODE_VIDEO,
 	.format = MIPI_DSI_FMT_RGB888,
 	.supply_names = ts8550b_supply_names,
 	.num_supplies = ARRAY_SIZE(ts8550b_supply_names),
 	.panel_sleep_delay = 80, /* panel need extra 80ms for sleep out cmd */
 };

 static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
 {
 	const struct st7701_panel_desc *desc;
 	struct st7701 *st7701;
 	int ret, i;

 	st7701 = devm_kzalloc(&dsi->dev, sizeof(*st7701), GFP_KERNEL);
 	if (!st7701)
 		return -ENOMEM;

 	desc = of_device_get_match_data(&dsi->dev);
 	dsi->mode_flags = desc->flags;
 	dsi->format = desc->format;
 	dsi->lanes = desc->lanes;

 	st7701->supplies = devm_kcalloc(&dsi->dev, desc->num_supplies,
 					sizeof(*st7701->supplies),
 					GFP_KERNEL);
 	if (!st7701->supplies)
 		return -ENOMEM;

 	for (i = 0; i < desc->num_supplies; i++)
 		st7701->supplies[i].supply = desc->supply_names[i];

 	ret = devm_regulator_bulk_get(&dsi->dev, desc->num_supplies,
 				      st7701->supplies);
 	if (ret < 0)
 		return ret;

 	st7701->reset = devm_gpiod_get(&dsi->dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(st7701->reset)) {
 		DRM_DEV_ERROR(&dsi->dev, "Couldn't get our reset GPIO\n");
 		return PTR_ERR(st7701->reset);
 	}

 	st7701->backlight = devm_of_find_backlight(&dsi->dev);
 	if (IS_ERR(st7701->backlight))
 		return PTR_ERR(st7701->backlight);

 	drm_panel_init(&st7701->panel);

 	/**
 	 * Once sleep out has been issued, ST7701 IC required to wait 120ms
 	 * before initiating new commands.
 	 *
 	 * On top of that some panels might need an extra delay to wait, so
 	 * add panel specific delay for those cases. As now this panel specific
 	 * delay information is referenced from those panel BSP driver, example
 	 * ts8550b and there is no valid documentation for that.
 	 */
 	st7701->sleep_delay = 120 + desc->panel_sleep_delay;
 	st7701->panel.funcs = &st7701_funcs;
 	st7701->panel.dev = &dsi->dev;

 	ret = drm_panel_add(&st7701->panel);
 	if (ret < 0)
 		return ret;

 	mipi_dsi_set_drvdata(dsi, st7701);
 	st7701->dsi = dsi;
 	st7701->desc = desc;

 	return mipi_dsi_attach(dsi);
 }

 static int st7701_dsi_remove(struct mipi_dsi_device *dsi)
 {
 	struct st7701 *st7701 = mipi_dsi_get_drvdata(dsi);

 	mipi_dsi_detach(dsi);
 	drm_panel_remove(&st7701->panel);

 	return 0;
 }

 static const struct of_device_id st7701_of_match[] = {
 	{ .compatible = "techstar,ts8550b", .data = &ts8550b_desc },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, st7701_of_match);

 static struct mipi_dsi_driver st7701_dsi_driver = {
 	.probe		= st7701_dsi_probe,
 	.remove		= st7701_dsi_remove,
 	.driver = {
 		.name		= "st7701",
 		.of_match_table	= st7701_of_match,
 	},
 };
 module_mipi_dsi_driver(st7701_dsi_driver);

 MODULE_AUTHOR("Jagan Teki <jagan@amarulasolutions.com>");
 MODULE_DESCRIPTION("Sitronix ST7701 LCD Panel Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2019, Amarula Solutions.
	* Author: Jagan Teki <jagan@amarulasolutions.com>
	*/

	#include <drm/drm_mipi_dsi.h>
	#include <drm/drm_modes.h>
	#include <drm/drm_panel.h>
	#include <drm/drm_print.h>

	#include <linux/backlight.h>
	#include <linux/gpio/consumer.h>
	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/regulator/consumer.h>

	#include <video/mipi_display.h>

	/* Command2 BKx selection command */
	#define DSI_CMD2BKX_SEL 0xFF

	/* Command2, BK0 commands */
	#define DSI_CMD2_BK0_PVGAMCTRL 0xB0 /* Positive Voltage Gamma Control */
	#define DSI_CMD2_BK0_NVGAMCTRL 0xB1 /* Negative Voltage Gamma Control */
	#define DSI_CMD2_BK0_LNESET 0xC0 /* Display Line setting */
	#define DSI_CMD2_BK0_PORCTRL 0xC1 /* Porch control */
	#define DSI_CMD2_BK0_INVSEL 0xC2 /* Inversion selection, Frame Rate Control */

	/* Command2, BK1 commands */
	#define DSI_CMD2_BK1_VRHS 0xB0 /* Vop amplitude setting */
	#define DSI_CMD2_BK1_VCOM 0xB1 /* VCOM amplitude setting */
	#define DSI_CMD2_BK1_VGHSS 0xB2 /* VGH Voltage setting */
	#define DSI_CMD2_BK1_TESTCMD 0xB3 /* TEST Command Setting */
	#define DSI_CMD2_BK1_VGLS 0xB5 /* VGL Voltage setting */
	#define DSI_CMD2_BK1_PWCTLR1 0xB7 /* Power Control 1 */
	#define DSI_CMD2_BK1_PWCTLR2 0xB8 /* Power Control 2 */
	#define DSI_CMD2_BK1_SPD1 0xC1 /* Source pre_drive timing set1 */
	#define DSI_CMD2_BK1_SPD2 0xC2 /* Source EQ2 Setting */
	#define DSI_CMD2_BK1_MIPISET1 0xD0 /* MIPI Setting 1 */

	/**
	* Command2 with BK function selection.
	*
	* BIT[4, 0]: [CN2, BKXSEL]
	* 10 = CMD2BK0, Command2 BK0
	* 11 = CMD2BK1, Command2 BK1
	* 00 = Command2 disable
	*/
	#define DSI_CMD2BK1_SEL 0x11
	#define DSI_CMD2BK0_SEL 0x10
	#define DSI_CMD2BKX_SEL_NONE 0x00

	/* Command2, BK0 bytes */
	#define DSI_LINESET_LINE 0x69
	#define DSI_LINESET_LDE_EN BIT(7)
	#define DSI_LINESET_LINEDELTA GENMASK(1, 0)
	#define DSI_CMD2_BK0_LNESET_B1 DSI_LINESET_LINEDELTA
	#define DSI_CMD2_BK0_LNESET_B0 (DSI_LINESET_LDE_EN \| DSI_LINESET_LINE)
	#define DSI_INVSEL_DEFAULT GENMASK(5, 4)
	#define DSI_INVSEL_NLINV GENMASK(2, 0)
	#define DSI_INVSEL_RTNI GENMASK(2, 1)
	#define DSI_CMD2_BK0_INVSEL_B1 DSI_INVSEL_RTNI
	#define DSI_CMD2_BK0_INVSEL_B0 (DSI_INVSEL_DEFAULT \| DSI_INVSEL_NLINV)
	#define DSI_CMD2_BK0_PORCTRL_B0(m) ((m)->vtotal - (m)->vsync_end)
	#define DSI_CMD2_BK0_PORCTRL_B1(m) ((m)->vsync_start - (m)->vdisplay)

	/* Command2, BK1 bytes */
	#define DSI_CMD2_BK1_VRHA_SET 0x45
	#define DSI_CMD2_BK1_VCOM_SET 0x13
	#define DSI_CMD2_BK1_VGHSS_SET GENMASK(2, 0)
	#define DSI_CMD2_BK1_TESTCMD_VAL BIT(7)
	#define DSI_VGLS_DEFAULT BIT(6)
	#define DSI_VGLS_SEL GENMASK(2, 0)
	#define DSI_CMD2_BK1_VGLS_SET (DSI_VGLS_DEFAULT \| DSI_VGLS_SEL)
	#define DSI_PWCTLR1_AP BIT(7) /* Gamma OP bias, max */
	#define DSI_PWCTLR1_APIS BIT(2) /* Source OP input bias, min */
	#define DSI_PWCTLR1_APOS BIT(0) /* Source OP output bias, min */
	#define DSI_CMD2_BK1_PWCTLR1_SET (DSI_PWCTLR1_AP \| DSI_PWCTLR1_APIS \| \
	DSI_PWCTLR1_APOS)
	#define DSI_PWCTLR2_AVDD BIT(5) /* AVDD 6.6v */
	#define DSI_PWCTLR2_AVCL 0x0 /* AVCL -4.4v */
	#define DSI_CMD2_BK1_PWCTLR2_SET (DSI_PWCTLR2_AVDD \| DSI_PWCTLR2_AVCL)
	#define DSI_SPD1_T2D BIT(3)
	#define DSI_CMD2_BK1_SPD1_SET (GENMASK(6, 4) \| DSI_SPD1_T2D)
	#define DSI_CMD2_BK1_SPD2_SET DSI_CMD2_BK1_SPD1_SET
	#define DSI_MIPISET1_EOT_EN BIT(3)
	#define DSI_CMD2_BK1_MIPISET1_SET (BIT(7) \| DSI_MIPISET1_EOT_EN)

	struct st7701_panel_desc {
	const struct drm_display_mode *mode;
	unsigned int lanes;
	unsigned long flags;
	enum mipi_dsi_pixel_format format;
	const char const supply_names;
	unsigned int num_supplies;
	unsigned int panel_sleep_delay;
	};

	struct st7701 {
	struct drm_panel panel;
	struct mipi_dsi_device *dsi;
	const struct st7701_panel_desc *desc;

	struct backlight_device *backlight;
	struct regulator_bulk_data *supplies;
	struct gpio_desc *reset;
	unsigned int sleep_delay;
	};

	static inline struct st7701 panel_to_st7701(struct drm_panel panel)
	{
	return container_of(panel, struct st7701, panel);
	}

	static inline int st7701_dsi_write(struct st7701 st7701, const void seq,
	size_t len)
	{
	return mipi_dsi_dcs_write_buffer(st7701->dsi, seq, len);
	}

	#define ST7701_DSI(st7701, seq...) \
	{ \
	const u8 d[] = { seq }; \
	st7701_dsi_write(st7701, d, ARRAY_SIZE(d)); \
	}

	static void st7701_init_sequence(struct st7701 *st7701)
	{
	const struct drm_display_mode *mode = st7701->desc->mode;

	ST7701_DSI(st7701, MIPI_DCS_SOFT_RESET, 0x00);

	/* We need to wait 5ms before sending new commands */
	msleep(5);

	ST7701_DSI(st7701, MIPI_DCS_EXIT_SLEEP_MODE, 0x00);

	msleep(st7701->sleep_delay);

	/* Command2, BK0 */
	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
	0x77, 0x01, 0x00, 0x00, DSI_CMD2BK0_SEL);
	ST7701_DSI(st7701, DSI_CMD2_BK0_PVGAMCTRL, 0x00, 0x0E, 0x15, 0x0F,
	0x11, 0x08, 0x08, 0x08, 0x08, 0x23, 0x04, 0x13, 0x12,
	0x2B, 0x34, 0x1F);
	ST7701_DSI(st7701, DSI_CMD2_BK0_NVGAMCTRL, 0x00, 0x0E, 0x95, 0x0F,
	0x13, 0x07, 0x09, 0x08, 0x08, 0x22, 0x04, 0x10, 0x0E,
	0x2C, 0x34, 0x1F);
	ST7701_DSI(st7701, DSI_CMD2_BK0_LNESET,
	DSI_CMD2_BK0_LNESET_B0, DSI_CMD2_BK0_LNESET_B1);
	ST7701_DSI(st7701, DSI_CMD2_BK0_PORCTRL,
	DSI_CMD2_BK0_PORCTRL_B0(mode),
	DSI_CMD2_BK0_PORCTRL_B1(mode));
	ST7701_DSI(st7701, DSI_CMD2_BK0_INVSEL,
	DSI_CMD2_BK0_INVSEL_B0, DSI_CMD2_BK0_INVSEL_B1);

	/* Command2, BK1 */
	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
	0x77, 0x01, 0x00, 0x00, DSI_CMD2BK1_SEL);
	ST7701_DSI(st7701, DSI_CMD2_BK1_VRHS, DSI_CMD2_BK1_VRHA_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_VCOM, DSI_CMD2_BK1_VCOM_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_VGHSS, DSI_CMD2_BK1_VGHSS_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_TESTCMD, DSI_CMD2_BK1_TESTCMD_VAL);
	ST7701_DSI(st7701, DSI_CMD2_BK1_VGLS, DSI_CMD2_BK1_VGLS_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_PWCTLR1, DSI_CMD2_BK1_PWCTLR1_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_PWCTLR2, DSI_CMD2_BK1_PWCTLR2_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_SPD1, DSI_CMD2_BK1_SPD1_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_SPD2, DSI_CMD2_BK1_SPD2_SET);
	ST7701_DSI(st7701, DSI_CMD2_BK1_MIPISET1, DSI_CMD2_BK1_MIPISET1_SET);

	/**
	* ST7701_SPEC_V1.2 is unable to provide enough information above this
	* specific command sequence, so grab the same from vendor BSP driver.
	*/
	ST7701_DSI(st7701, 0xE0, 0x00, 0x00, 0x02);
	ST7701_DSI(st7701, 0xE1, 0x0B, 0x00, 0x0D, 0x00, 0x0C, 0x00, 0x0E,
	0x00, 0x00, 0x44, 0x44);
	ST7701_DSI(st7701, 0xE2, 0x33, 0x33, 0x44, 0x44, 0x64, 0x00, 0x66,
	0x00, 0x65, 0x00, 0x67, 0x00, 0x00);
	ST7701_DSI(st7701, 0xE3, 0x00, 0x00, 0x33, 0x33);
	ST7701_DSI(st7701, 0xE4, 0x44, 0x44);
	ST7701_DSI(st7701, 0xE5, 0x0C, 0x78, 0x3C, 0xA0, 0x0E, 0x78, 0x3C,
	0xA0, 0x10, 0x78, 0x3C, 0xA0, 0x12, 0x78, 0x3C, 0xA0);
	ST7701_DSI(st7701, 0xE6, 0x00, 0x00, 0x33, 0x33);
	ST7701_DSI(st7701, 0xE7, 0x44, 0x44);
	ST7701_DSI(st7701, 0xE8, 0x0D, 0x78, 0x3C, 0xA0, 0x0F, 0x78, 0x3C,
	0xA0, 0x11, 0x78, 0x3C, 0xA0, 0x13, 0x78, 0x3C, 0xA0);
	ST7701_DSI(st7701, 0xEB, 0x02, 0x02, 0x39, 0x39, 0xEE, 0x44, 0x00);
	ST7701_DSI(st7701, 0xEC, 0x00, 0x00);
	ST7701_DSI(st7701, 0xED, 0xFF, 0xF1, 0x04, 0x56, 0x72, 0x3F, 0xFF,
	0xFF, 0xFF, 0xFF, 0xF3, 0x27, 0x65, 0x40, 0x1F, 0xFF);

	/* disable Command2 */
	ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
	0x77, 0x01, 0x00, 0x00, DSI_CMD2BKX_SEL_NONE);
	}

	static int st7701_prepare(struct drm_panel *panel)
	{
	struct st7701 *st7701 = panel_to_st7701(panel);
	int ret;

	gpiod_set_value(st7701->reset, 0);

	ret = regulator_bulk_enable(st7701->desc->num_supplies,
	st7701->supplies);
	if (ret < 0)
	return ret;
	msleep(20);

	gpiod_set_value(st7701->reset, 1);
	msleep(150);

	st7701_init_sequence(st7701);

	return 0;
	}

	static int st7701_enable(struct drm_panel *panel)
	{
	struct st7701 *st7701 = panel_to_st7701(panel);

	ST7701_DSI(st7701, MIPI_DCS_SET_DISPLAY_ON, 0x00);
	backlight_enable(st7701->backlight);

	return 0;
	}

	static int st7701_disable(struct drm_panel *panel)
	{
	struct st7701 *st7701 = panel_to_st7701(panel);

	backlight_disable(st7701->backlight);
	ST7701_DSI(st7701, MIPI_DCS_SET_DISPLAY_OFF, 0x00);

	return 0;
	}

	static int st7701_unprepare(struct drm_panel *panel)
	{
	struct st7701 *st7701 = panel_to_st7701(panel);

	ST7701_DSI(st7701, MIPI_DCS_ENTER_SLEEP_MODE, 0x00);

	msleep(st7701->sleep_delay);

	gpiod_set_value(st7701->reset, 0);

	/**
	* During the Resetting period, the display will be blanked
	* (The display is entering blanking sequence, which maximum
	* time is 120 ms, when Reset Starts in Sleep Out –mode. The
	* display remains the blank state in Sleep In –mode.) and
	* then return to Default condition for Hardware Reset.
	*
	* So we need wait sleep_delay time to make sure reset completed.
	*/
	msleep(st7701->sleep_delay);

	regulator_bulk_disable(st7701->desc->num_supplies, st7701->supplies);

	return 0;
	}

	static int st7701_get_modes(struct drm_panel *panel)
	{
	struct st7701 *st7701 = panel_to_st7701(panel);
	const struct drm_display_mode *desc_mode = st7701->desc->mode;
	struct drm_display_mode *mode;

	mode = drm_mode_duplicate(panel->drm, desc_mode);
	if (!mode) {
	DRM_DEV_ERROR(&st7701->dsi->dev,
	"failed to add mode %ux%ux@%u\n",
	desc_mode->hdisplay, desc_mode->vdisplay,
	desc_mode->vrefresh);
	return -ENOMEM;
	}

	drm_mode_set_name(mode);
	drm_mode_probed_add(panel->connector, mode);

	panel->connector->display_info.width_mm = desc_mode->width_mm;
	panel->connector->display_info.height_mm = desc_mode->height_mm;

	return 1;
	}

	static const struct drm_panel_funcs st7701_funcs = {
	.disable = st7701_disable,
	.unprepare = st7701_unprepare,
	.prepare = st7701_prepare,
	.enable = st7701_enable,
	.get_modes = st7701_get_modes,
	};

	static const struct drm_display_mode ts8550b_mode = {
	.clock = 27500,

	.hdisplay = 480,
	.hsync_start = 480 + 38,
	.hsync_end = 480 + 38 + 12,
	.htotal = 480 + 38 + 12 + 12,

	.vdisplay = 854,
	.vsync_start = 854 + 4,
	.vsync_end = 854 + 4 + 8,
	.vtotal = 854 + 4 + 8 + 18,

	.width_mm = 69,
	.height_mm = 139,

	.type = DRM_MODE_TYPE_DRIVER \| DRM_MODE_TYPE_PREFERRED,
	};

	static const char * const ts8550b_supply_names[] = {
	"VCC",
	"IOVCC",
	};

	static const struct st7701_panel_desc ts8550b_desc = {
	.mode = &ts8550b_mode,
	.lanes = 2,
	.flags = MIPI_DSI_MODE_VIDEO,
	.format = MIPI_DSI_FMT_RGB888,
	.supply_names = ts8550b_supply_names,
	.num_supplies = ARRAY_SIZE(ts8550b_supply_names),
	.panel_sleep_delay = 80, /* panel need extra 80ms for sleep out cmd */
	};

	static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
	{
	const struct st7701_panel_desc *desc;
	struct st7701 *st7701;
	int ret, i;

	st7701 = devm_kzalloc(&dsi->dev, sizeof(*st7701), GFP_KERNEL);
	if (!st7701)
	return -ENOMEM;

	desc = of_device_get_match_data(&dsi->dev);
	dsi->mode_flags = desc->flags;
	dsi->format = desc->format;
	dsi->lanes = desc->lanes;

	st7701->supplies = devm_kcalloc(&dsi->dev, desc->num_supplies,
	sizeof(*st7701->supplies),
	GFP_KERNEL);
	if (!st7701->supplies)
	return -ENOMEM;

	for (i = 0; i < desc->num_supplies; i++)
	st7701->supplies[i].supply = desc->supply_names[i];

	ret = devm_regulator_bulk_get(&dsi->dev, desc->num_supplies,
	st7701->supplies);
	if (ret < 0)
	return ret;

	st7701->reset = devm_gpiod_get(&dsi->dev, "reset", GPIOD_OUT_LOW);
	if (IS_ERR(st7701->reset)) {
	DRM_DEV_ERROR(&dsi->dev, "Couldn't get our reset GPIO\n");
	return PTR_ERR(st7701->reset);
	}

	st7701->backlight = devm_of_find_backlight(&dsi->dev);
	if (IS_ERR(st7701->backlight))
	return PTR_ERR(st7701->backlight);

	drm_panel_init(&st7701->panel);

	/**
	* Once sleep out has been issued, ST7701 IC required to wait 120ms
	* before initiating new commands.
	*
	* On top of that some panels might need an extra delay to wait, so
	* add panel specific delay for those cases. As now this panel specific
	* delay information is referenced from those panel BSP driver, example
	* ts8550b and there is no valid documentation for that.
	*/
	st7701->sleep_delay = 120 + desc->panel_sleep_delay;
	st7701->panel.funcs = &st7701_funcs;
	st7701->panel.dev = &dsi->dev;

	ret = drm_panel_add(&st7701->panel);
	if (ret < 0)
	return ret;

	mipi_dsi_set_drvdata(dsi, st7701);
	st7701->dsi = dsi;
	st7701->desc = desc;

	return mipi_dsi_attach(dsi);
	}

	static int st7701_dsi_remove(struct mipi_dsi_device *dsi)
	{
	struct st7701 *st7701 = mipi_dsi_get_drvdata(dsi);

	mipi_dsi_detach(dsi);
	drm_panel_remove(&st7701->panel);

	return 0;
	}

	static const struct of_device_id st7701_of_match[] = {
	{ .compatible = "techstar,ts8550b", .data = &ts8550b_desc },
	{ }
	};
	MODULE_DEVICE_TABLE(of, st7701_of_match);

	static struct mipi_dsi_driver st7701_dsi_driver = {
	.probe = st7701_dsi_probe,
	.remove = st7701_dsi_remove,
	.driver = {
	.name = "st7701",
	.of_match_table = st7701_of_match,
	},
	};
	module_mipi_dsi_driver(st7701_dsi_driver);

	MODULE_AUTHOR("Jagan Teki <jagan@amarulasolutions.com>");
	MODULE_DESCRIPTION("Sitronix ST7701 LCD Panel Driver");
	MODULE_LICENSE("GPL");