drivers/gpu/drm/panel/panel-sitronix-st7789v.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017 Free Electrons
 */

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

#include <video/mipi_display.h>
#include <linux/media-bus-format.h>

#include <drm/drm_device.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>

#define ST7789V_RAMCTRL_CMD		0xb0
#define ST7789V_RAMCTRL_RM_RGB			BIT(4)
#define ST7789V_RAMCTRL_DM_RGB			BIT(0)
#define ST7789V_RAMCTRL_MAGIC			(3 << 6)
#define ST7789V_RAMCTRL_EPF(n)			(((n) & 3) << 4)

#define ST7789V_RGBCTRL_CMD		0xb1
#define ST7789V_RGBCTRL_WO			BIT(7)
#define ST7789V_RGBCTRL_RCM(n)			(((n) & 3) << 5)
#define ST7789V_RGBCTRL_VSYNC_HIGH		BIT(3)
#define ST7789V_RGBCTRL_HSYNC_HIGH		BIT(2)
#define ST7789V_RGBCTRL_PCLK_FALLING		BIT(1)
#define ST7789V_RGBCTRL_DE_LOW			BIT(0)
#define ST7789V_RGBCTRL_VBP(n)			((n) & 0x7f)
#define ST7789V_RGBCTRL_HBP(n)			((n) & 0x1f)

#define ST7789V_PORCTRL_CMD		0xb2
#define ST7789V_PORCTRL_IDLE_BP(n)		(((n) & 0xf) << 4)
#define ST7789V_PORCTRL_IDLE_FP(n)		((n) & 0xf)
#define ST7789V_PORCTRL_PARTIAL_BP(n)		(((n) & 0xf) << 4)
#define ST7789V_PORCTRL_PARTIAL_FP(n)		((n) & 0xf)

#define ST7789V_GCTRL_CMD		0xb7
#define ST7789V_GCTRL_VGHS(n)			(((n) & 7) << 4)
#define ST7789V_GCTRL_VGLS(n)			((n) & 7)

#define ST7789V_VCOMS_CMD		0xbb

#define ST7789V_LCMCTRL_CMD		0xc0
#define ST7789V_LCMCTRL_XBGR			BIT(5)
#define ST7789V_LCMCTRL_XMX			BIT(3)
#define ST7789V_LCMCTRL_XMH			BIT(2)

#define ST7789V_VDVVRHEN_CMD		0xc2
#define ST7789V_VDVVRHEN_CMDEN			BIT(0)

#define ST7789V_VRHS_CMD		0xc3

#define ST7789V_VDVS_CMD		0xc4

#define ST7789V_FRCTRL2_CMD		0xc6

#define ST7789V_PWCTRL1_CMD		0xd0
#define ST7789V_PWCTRL1_MAGIC			0xa4
#define ST7789V_PWCTRL1_AVDD(n)			(((n) & 3) << 6)
#define ST7789V_PWCTRL1_AVCL(n)			(((n) & 3) << 4)
#define ST7789V_PWCTRL1_VDS(n)			((n) & 3)

#define ST7789V_PVGAMCTRL_CMD		0xe0
#define ST7789V_PVGAMCTRL_JP0(n)		(((n) & 3) << 4)
#define ST7789V_PVGAMCTRL_JP1(n)		(((n) & 3) << 4)
#define ST7789V_PVGAMCTRL_VP0(n)		((n) & 0xf)
#define ST7789V_PVGAMCTRL_VP1(n)		((n) & 0x3f)
#define ST7789V_PVGAMCTRL_VP2(n)		((n) & 0x3f)
#define ST7789V_PVGAMCTRL_VP4(n)		((n) & 0x1f)
#define ST7789V_PVGAMCTRL_VP6(n)		((n) & 0x1f)
#define ST7789V_PVGAMCTRL_VP13(n)		((n) & 0xf)
#define ST7789V_PVGAMCTRL_VP20(n)		((n) & 0x7f)
#define ST7789V_PVGAMCTRL_VP27(n)		((n) & 7)
#define ST7789V_PVGAMCTRL_VP36(n)		(((n) & 7) << 4)
#define ST7789V_PVGAMCTRL_VP43(n)		((n) & 0x7f)
#define ST7789V_PVGAMCTRL_VP50(n)		((n) & 0xf)
#define ST7789V_PVGAMCTRL_VP57(n)		((n) & 0x1f)
#define ST7789V_PVGAMCTRL_VP59(n)		((n) & 0x1f)
#define ST7789V_PVGAMCTRL_VP61(n)		((n) & 0x3f)
#define ST7789V_PVGAMCTRL_VP62(n)		((n) & 0x3f)
#define ST7789V_PVGAMCTRL_VP63(n)		(((n) & 0xf) << 4)

#define ST7789V_NVGAMCTRL_CMD		0xe1
#define ST7789V_NVGAMCTRL_JN0(n)		(((n) & 3) << 4)
#define ST7789V_NVGAMCTRL_JN1(n)		(((n) & 3) << 4)
#define ST7789V_NVGAMCTRL_VN0(n)		((n) & 0xf)
#define ST7789V_NVGAMCTRL_VN1(n)		((n) & 0x3f)
#define ST7789V_NVGAMCTRL_VN2(n)		((n) & 0x3f)
#define ST7789V_NVGAMCTRL_VN4(n)		((n) & 0x1f)
#define ST7789V_NVGAMCTRL_VN6(n)		((n) & 0x1f)
#define ST7789V_NVGAMCTRL_VN13(n)		((n) & 0xf)
#define ST7789V_NVGAMCTRL_VN20(n)		((n) & 0x7f)
#define ST7789V_NVGAMCTRL_VN27(n)		((n) & 7)
#define ST7789V_NVGAMCTRL_VN36(n)		(((n) & 7) << 4)
#define ST7789V_NVGAMCTRL_VN43(n)		((n) & 0x7f)
#define ST7789V_NVGAMCTRL_VN50(n)		((n) & 0xf)
#define ST7789V_NVGAMCTRL_VN57(n)		((n) & 0x1f)
#define ST7789V_NVGAMCTRL_VN59(n)		((n) & 0x1f)
#define ST7789V_NVGAMCTRL_VN61(n)		((n) & 0x3f)
#define ST7789V_NVGAMCTRL_VN62(n)		((n) & 0x3f)
#define ST7789V_NVGAMCTRL_VN63(n)		(((n) & 0xf) << 4)

#define ST7789V_TEST(val, func)			\
	do {					\
		if ((val = (func)))		\
			return val;		\
	} while (0)

#define ST7789V_IDS { 0x85, 0x85, 0x52 }
#define ST7789V_IDS_SIZE 3

struct st7789_panel_info {
	const struct drm_display_mode *mode;
	u32 bus_format;
	u32 bus_flags;
	bool invert_mode;
	bool partial_mode;
	u16 partial_start;
	u16 partial_end;
};

struct st7789v {
	struct drm_panel panel;
	const struct st7789_panel_info *info;
	struct spi_device *spi;
	struct gpio_desc *reset;
	struct regulator *power;
	enum drm_panel_orientation orientation;
};

enum st7789v_prefix {
	ST7789V_COMMAND = 0,
	ST7789V_DATA = 1,
};

static inline struct st7789v *panel_to_st7789v(struct drm_panel *panel)
{
	return container_of(panel, struct st7789v, panel);
}

static int st7789v_spi_write(struct st7789v *ctx, enum st7789v_prefix prefix,
			     u8 data)
{
	struct spi_transfer xfer = { };
	u16 txbuf = ((prefix & 1) << 8) | data;

	xfer.tx_buf = &txbuf;
	xfer.len = sizeof(txbuf);

	return spi_sync_transfer(ctx->spi, &xfer, 1);
}

static int st7789v_write_command(struct st7789v *ctx, u8 cmd)
{
	return st7789v_spi_write(ctx, ST7789V_COMMAND, cmd);
}

static int st7789v_write_data(struct st7789v *ctx, u8 cmd)
{
	return st7789v_spi_write(ctx, ST7789V_DATA, cmd);
}

static int st7789v_read_data(struct st7789v *ctx, u8 cmd, u8 *buf,
			     unsigned int len)
{
	struct spi_transfer xfer[2] = { };
	struct spi_message msg;
	u16 txbuf = ((ST7789V_COMMAND & 1) << 8) | cmd;
	u16 rxbuf[4] = {};
	u8 bit9 = 0;
	int ret, i;

	switch (len) {
	case 1:
	case 3:
	case 4:
		break;
	default:
		return -EOPNOTSUPP;
	}

	spi_message_init(&msg);

	xfer[0].tx_buf = &txbuf;
	xfer[0].len = sizeof(txbuf);
	spi_message_add_tail(&xfer[0], &msg);

	xfer[1].rx_buf = rxbuf;
	xfer[1].len = len * 2;
	spi_message_add_tail(&xfer[1], &msg);

	ret = spi_sync(ctx->spi, &msg);
	if (ret)
		return ret;

	for (i = 0; i < len; i++) {
		buf[i] = rxbuf[i] >> i | (bit9 << (9 - i));
		if (i)
			bit9 = rxbuf[i] & GENMASK(i - 1, 0);
	}

	return 0;
}

static int st7789v_check_id(struct drm_panel *panel)
{
	const u8 st7789v_ids[ST7789V_IDS_SIZE] = ST7789V_IDS;
	struct st7789v *ctx = panel_to_st7789v(panel);
	bool invalid_ids = false;
	int ret, i;
	u8 ids[3];

	if (ctx->spi->mode & SPI_NO_RX)
		return 0;

	ret = st7789v_read_data(ctx, MIPI_DCS_GET_DISPLAY_ID, ids, ST7789V_IDS_SIZE);
	if (ret)
		return ret;

	for (i = 0; i < ST7789V_IDS_SIZE; i++) {
		if (ids[i] != st7789v_ids[i]) {
			invalid_ids = true;
			break;
		}
	}

	if (invalid_ids)
		return -EIO;

	return 0;
}

static const struct drm_display_mode default_mode = {
	.clock = 7000,
	.hdisplay = 240,
	.hsync_start = 240 + 38,
	.hsync_end = 240 + 38 + 10,
	.htotal = 240 + 38 + 10 + 10,
	.vdisplay = 320,
	.vsync_start = 320 + 8,
	.vsync_end = 320 + 8 + 4,
	.vtotal = 320 + 8 + 4 + 4,
	.width_mm = 61,
	.height_mm = 103,
	.flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
};

static const struct drm_display_mode t28cp45tn89_mode = {
	.clock = 6008,
	.hdisplay = 240,
	.hsync_start = 240 + 38,
	.hsync_end = 240 + 38 + 10,
	.htotal = 240 + 38 + 10 + 10,
	.vdisplay = 320,
	.vsync_start = 320 + 8,
	.vsync_end = 320 + 8 + 4,
	.vtotal = 320 + 8 + 4 + 4,
	.width_mm = 43,
	.height_mm = 57,
	.flags = DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC,
};

static const struct drm_display_mode et028013dma_mode = {
	.clock = 3000,
	.hdisplay = 240,
	.hsync_start = 240 + 38,
	.hsync_end = 240 + 38 + 10,
	.htotal = 240 + 38 + 10 + 10,
	.vdisplay = 320,
	.vsync_start = 320 + 8,
	.vsync_end = 320 + 8 + 4,
	.vtotal = 320 + 8 + 4 + 4,
	.width_mm = 43,
	.height_mm = 58,
	.flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
};

static const struct drm_display_mode jt240mhqs_hwt_ek_e3_mode = {
	.clock = 6000,
	.hdisplay = 240,
	.hsync_start = 240 + 28,
	.hsync_end = 240 + 28 + 10,
	.htotal = 240 + 28 + 10 + 10,
	.vdisplay = 280,
	.vsync_start = 280 + 8,
	.vsync_end = 280 + 8 + 4,
	.vtotal = 280 + 8 + 4 + 4,
	.width_mm = 43,
	.height_mm = 37,
	.flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
};

static const struct st7789_panel_info default_panel = {
	.mode = &default_mode,
	.invert_mode = true,
	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
	.bus_flags = DRM_BUS_FLAG_DE_HIGH |
		     DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE,
};

static const struct st7789_panel_info t28cp45tn89_panel = {
	.mode = &t28cp45tn89_mode,
	.invert_mode = false,
	.bus_format = MEDIA_BUS_FMT_RGB565_1X16,
	.bus_flags = DRM_BUS_FLAG_DE_HIGH |
		     DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
};

static const struct st7789_panel_info et028013dma_panel = {
	.mode = &et028013dma_mode,
	.invert_mode = true,
	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
	.bus_flags = DRM_BUS_FLAG_DE_HIGH |
		     DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
};

static const struct st7789_panel_info jt240mhqs_hwt_ek_e3_panel = {
	.mode = &jt240mhqs_hwt_ek_e3_mode,
	.invert_mode = true,
	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
	.bus_flags = DRM_BUS_FLAG_DE_HIGH |
		     DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE,
	.partial_mode = true,
	.partial_start = 38,
	.partial_end = 318,
};

static int st7789v_get_modes(struct drm_panel *panel,
			     struct drm_connector *connector)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	struct drm_display_mode *mode;

	mode = drm_mode_duplicate(connector->dev, ctx->info->mode);
	if (!mode) {
		dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
			ctx->info->mode->hdisplay, ctx->info->mode->vdisplay,
			drm_mode_vrefresh(ctx->info->mode));
		return -ENOMEM;
	}

	drm_mode_set_name(mode);

	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
	drm_mode_probed_add(connector, mode);

	connector->display_info.bpc = 6;
	connector->display_info.width_mm = ctx->info->mode->width_mm;
	connector->display_info.height_mm = ctx->info->mode->height_mm;
	connector->display_info.bus_flags = ctx->info->bus_flags;
	drm_display_info_set_bus_formats(&connector->display_info,
					 &ctx->info->bus_format, 1);

	/*
	 * TODO: Remove once all drm drivers call
	 * drm_connector_set_orientation_from_panel()
	 */
	drm_connector_set_panel_orientation(connector, ctx->orientation);

	return 1;
}

static enum drm_panel_orientation st7789v_get_orientation(struct drm_panel *p)
{
	struct st7789v *ctx = panel_to_st7789v(p);

	return ctx->orientation;
}

static int st7789v_prepare(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	u8 mode, pixel_fmt, polarity;
	int ret;

	if (!ctx->info->partial_mode)
		mode = ST7789V_RGBCTRL_WO;
	else
		mode = 0;

	switch (ctx->info->bus_format) {
	case MEDIA_BUS_FMT_RGB666_1X18:
		pixel_fmt = MIPI_DCS_PIXEL_FMT_18BIT;
		break;
	case MEDIA_BUS_FMT_RGB565_1X16:
		pixel_fmt = MIPI_DCS_PIXEL_FMT_16BIT;
		break;
	default:
		dev_err(panel->dev, "unsupported bus format: %d\n",
			ctx->info->bus_format);
		return -EINVAL;
	}

	pixel_fmt = (pixel_fmt << 4) | pixel_fmt;

	polarity = 0;
	if (ctx->info->mode->flags & DRM_MODE_FLAG_PVSYNC)
		polarity |= ST7789V_RGBCTRL_VSYNC_HIGH;
	if (ctx->info->mode->flags & DRM_MODE_FLAG_PHSYNC)
		polarity |= ST7789V_RGBCTRL_HSYNC_HIGH;
	if (ctx->info->bus_flags & DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE)
		polarity |= ST7789V_RGBCTRL_PCLK_FALLING;
	if (ctx->info->bus_flags & DRM_BUS_FLAG_DE_LOW)
		polarity |= ST7789V_RGBCTRL_DE_LOW;

	ret = regulator_enable(ctx->power);
	if (ret)
		return ret;

	gpiod_set_value(ctx->reset, 1);
	msleep(30);
	gpiod_set_value(ctx->reset, 0);
	msleep(120);

	/*
	 * Avoid failing if the IDs are invalid in case the Rx bus width
	 * description is missing.
	 */
	ret = st7789v_check_id(panel);
	if (ret)
		dev_warn(panel->dev, "Unrecognized panel IDs");

	ST7789V_TEST(ret, st7789v_write_command(ctx, MIPI_DCS_EXIT_SLEEP_MODE));

	/* We need to wait 120ms after a sleep out command */
	msleep(120);

	ST7789V_TEST(ret, st7789v_write_command(ctx,
						MIPI_DCS_SET_ADDRESS_MODE));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0));

	ST7789V_TEST(ret, st7789v_write_command(ctx,
						MIPI_DCS_SET_PIXEL_FORMAT));
	ST7789V_TEST(ret, st7789v_write_data(ctx, pixel_fmt));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_PORCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0xc));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0xc));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PORCTRL_IDLE_BP(3) |
					     ST7789V_PORCTRL_IDLE_FP(3)));
	ST7789V_TEST(ret, st7789v_write_data(ctx,
					     ST7789V_PORCTRL_PARTIAL_BP(3) |
					     ST7789V_PORCTRL_PARTIAL_FP(3)));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_GCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_GCTRL_VGLS(5) |
					     ST7789V_GCTRL_VGHS(3)));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_VCOMS_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0x2b));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_LCMCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_LCMCTRL_XMH |
					     ST7789V_LCMCTRL_XMX |
					     ST7789V_LCMCTRL_XBGR));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_VDVVRHEN_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_VDVVRHEN_CMDEN));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_VRHS_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0xf));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_VDVS_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0x20));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_FRCTRL2_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, 0xf));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_PWCTRL1_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PWCTRL1_MAGIC));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PWCTRL1_AVDD(2) |
					     ST7789V_PWCTRL1_AVCL(2) |
					     ST7789V_PWCTRL1_VDS(1)));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_PVGAMCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP63(0xd)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP1(0xca)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP2(0xe)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP4(8)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP6(9)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP13(7)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP20(0x2d)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP27(0xb) |
					     ST7789V_PVGAMCTRL_VP36(3)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP43(0x3d)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_JP1(3) |
					     ST7789V_PVGAMCTRL_VP50(4)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP57(0xa)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP59(0xa)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP61(0x1b)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_PVGAMCTRL_VP62(0x28)));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_NVGAMCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN63(0xd)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN1(0xca)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN2(0xf)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN4(8)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN6(8)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN13(7)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN20(0x2e)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN27(0xc) |
					     ST7789V_NVGAMCTRL_VN36(5)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN43(0x40)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_JN1(3) |
					     ST7789V_NVGAMCTRL_VN50(4)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN57(9)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN59(0xb)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN61(0x1b)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_NVGAMCTRL_VN62(0x28)));

	if (ctx->info->invert_mode) {
		ST7789V_TEST(ret, st7789v_write_command(ctx,
						MIPI_DCS_ENTER_INVERT_MODE));
	} else {
		ST7789V_TEST(ret, st7789v_write_command(ctx,
						MIPI_DCS_EXIT_INVERT_MODE));
	}

	if (ctx->info->partial_mode) {
		u8 area_data[4] = {
			(ctx->info->partial_start >> 8) & 0xff,
			(ctx->info->partial_start >> 0) & 0xff,
			((ctx->info->partial_end - 1) >> 8) & 0xff,
			((ctx->info->partial_end - 1) >> 0) & 0xff,
		};

		/* Caution: if userspace ever pushes a mode different from the
		 * expected one (i.e., the one advertised by get_modes), we'll
		 * add margins.
		 */

		ST7789V_TEST(ret, st7789v_write_command(
					  ctx, MIPI_DCS_ENTER_PARTIAL_MODE));

		ST7789V_TEST(ret, st7789v_write_command(
					  ctx, MIPI_DCS_SET_PAGE_ADDRESS));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[0]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[1]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[2]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[3]));

		ST7789V_TEST(ret, st7789v_write_command(
					  ctx, MIPI_DCS_SET_PARTIAL_ROWS));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[0]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[1]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[2]));
		ST7789V_TEST(ret, st7789v_write_data(ctx, area_data[3]));
	}

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_RAMCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_RAMCTRL_DM_RGB |
					     ST7789V_RAMCTRL_RM_RGB));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_RAMCTRL_EPF(3) |
					     ST7789V_RAMCTRL_MAGIC));

	ST7789V_TEST(ret, st7789v_write_command(ctx, ST7789V_RGBCTRL_CMD));
	ST7789V_TEST(ret, st7789v_write_data(ctx, mode |
					     ST7789V_RGBCTRL_RCM(2) |
					     polarity));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_RGBCTRL_VBP(8)));
	ST7789V_TEST(ret, st7789v_write_data(ctx, ST7789V_RGBCTRL_HBP(20)));

	return 0;
}

static int st7789v_enable(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);

	return st7789v_write_command(ctx, MIPI_DCS_SET_DISPLAY_ON);
}

static int st7789v_disable(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	int ret;

	ST7789V_TEST(ret, st7789v_write_command(ctx, MIPI_DCS_SET_DISPLAY_OFF));

	return 0;
}

static int st7789v_unprepare(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	int ret;

	ST7789V_TEST(ret, st7789v_write_command(ctx, MIPI_DCS_ENTER_SLEEP_MODE));

	regulator_disable(ctx->power);

	return 0;
}

static const struct drm_panel_funcs st7789v_drm_funcs = {
	.disable = st7789v_disable,
	.enable	= st7789v_enable,
	.get_modes = st7789v_get_modes,
	.get_orientation = st7789v_get_orientation,
	.prepare = st7789v_prepare,
	.unprepare = st7789v_unprepare,
};

static int st7789v_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct st7789v *ctx;
	int ret;

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

	spi_set_drvdata(spi, ctx);
	ctx->spi = spi;

	spi->bits_per_word = 9;
	ret = spi_setup(spi);
	if (ret < 0)
		return dev_err_probe(&spi->dev, ret, "Failed to setup spi\n");

	ctx->info = device_get_match_data(&spi->dev);

	drm_panel_init(&ctx->panel, dev, &st7789v_drm_funcs,
		       DRM_MODE_CONNECTOR_DPI);

	ctx->power = devm_regulator_get(dev, "power");
	ret = PTR_ERR_OR_ZERO(ctx->power);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to get regulator\n");

	ctx->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
	ret = PTR_ERR_OR_ZERO(ctx->reset);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to get reset line\n");

	ret = drm_panel_of_backlight(&ctx->panel);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to get backlight\n");

	of_drm_get_panel_orientation(spi->dev.of_node, &ctx->orientation);

	drm_panel_add(&ctx->panel);

	return 0;
}

static void st7789v_remove(struct spi_device *spi)
{
	struct st7789v *ctx = spi_get_drvdata(spi);

	drm_panel_remove(&ctx->panel);
}

static const struct spi_device_id st7789v_spi_id[] = {
	{ "st7789v", (unsigned long) &default_panel },
	{ "t28cp45tn89-v17", (unsigned long) &t28cp45tn89_panel },
	{ "et028013dma", (unsigned long) &et028013dma_panel },
	{ "jt240mhqs-hwt-ek-e3", (unsigned long) &jt240mhqs_hwt_ek_e3_panel },
	{ }
};
MODULE_DEVICE_TABLE(spi, st7789v_spi_id);

static const struct of_device_id st7789v_of_match[] = {
	{ .compatible = "sitronix,st7789v", .data = &default_panel },
	{ .compatible = "inanbo,t28cp45tn89-v17", .data = &t28cp45tn89_panel },
	{ .compatible = "edt,et028013dma", .data = &et028013dma_panel },
	{ .compatible = "jasonic,jt240mhqs-hwt-ek-e3",
	  .data = &jt240mhqs_hwt_ek_e3_panel },
	{ }
};
MODULE_DEVICE_TABLE(of, st7789v_of_match);

static struct spi_driver st7789v_driver = {
	.probe = st7789v_probe,
	.remove = st7789v_remove,
	.id_table = st7789v_spi_id,
	.driver = {
		.name = "st7789v",
		.of_match_table = st7789v_of_match,
	},
};
module_spi_driver(st7789v_driver);

MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_DESCRIPTION("Sitronix st7789v LCD Driver");
MODULE_LICENSE("GPL v2");