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// SPDX-License-Identifier: GPL-2.0-only
/*
 * LH24030C50 RGB panel driver based on the ST7789V controller.
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <video/display_timing.h>
#include <video/videomode.h>
#include <video/of_videomode.h>

#include <drm/drm_device.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#include <linux/media-bus-format.h>

struct st7789v {
	struct drm_panel panel;
	struct spi_device *spi;
	struct gpio_desc *reset;
	struct gpio_desc *sclk;
	struct gpio_desc *mosi;
	struct gpio_desc *cs;
	struct regulator *power;
};
static inline struct st7789v *panel_to_st7789v(struct drm_panel *panel)
{
	return container_of(panel, struct st7789v, panel);
}

static void st7789v_spi_bitbang(struct st7789v *ctx, int dc, u8 data)
{
	int i;

	gpiod_set_value_cansleep(ctx->cs, 0);
	udelay(1);
	gpiod_set_value_cansleep(ctx->sclk, 0);
	gpiod_set_value_cansleep(ctx->mosi, dc ? 1 : 0);
	udelay(2);
	gpiod_set_value_cansleep(ctx->sclk, 1);
	udelay(2);
	for (i = 0; i < 8; i++) {
		gpiod_set_value_cansleep(ctx->sclk, 0);
		gpiod_set_value_cansleep(ctx->mosi, (data >> (7 - i)) & 1);
		udelay(2);
		gpiod_set_value_cansleep(ctx->sclk, 1);
		udelay(2);
	}
	gpiod_set_value_cansleep(ctx->sclk, 0);
	udelay(1);
	gpiod_set_value_cansleep(ctx->cs, 1);
	udelay(1);
}

static int st7789v_write_command(struct st7789v *ctx, u8 cmd)
{
	st7789v_spi_bitbang(ctx, 0, cmd);
	return 0;
}

static int st7789v_write_data(struct st7789v *ctx, u8 data)
{
	st7789v_spi_bitbang(ctx, 1, data);
	return 0;
}

static void st7789v_spi_idle(struct st7789v *ctx)
{
	gpiod_set_value_cansleep(ctx->cs, 1);
	gpiod_set_value_cansleep(ctx->sclk, 0);
	gpiod_set_value_cansleep(ctx->mosi, 0);
}

static const struct drm_display_mode default_mode = {
	.clock = 7000,
	.hdisplay = 240,
	.hsync_start = 240,
	.hsync_end = 240 + 51,
	.htotal = 240 + 51 + 51,
	.vdisplay = 320,
	.vsync_start = 320,
	.vsync_end = 320 + 12,
	.vtotal = 320 + 12 + 12,
	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
};

static int st7789v_get_modes(struct drm_panel *panel,
			     struct drm_connector *connector)
{
	struct drm_display_mode *mode;
	const u32 bus_format = MEDIA_BUS_FMT_RGB666_1X18;
	const struct drm_display_mode *src_mode = &default_mode;
	struct videomode vm;

	if (!of_get_videomode(panel->dev->of_node, &vm, 0)) {
		struct drm_display_mode *dt_mode;

		dt_mode = drm_mode_create(connector->dev);
		if (dt_mode) {
			drm_display_mode_from_videomode(&vm, dt_mode);
			dt_mode->type = DRM_MODE_TYPE_DRIVER |
					DRM_MODE_TYPE_PREFERRED;
			src_mode = dt_mode;
		}
	}

	mode = drm_mode_duplicate(connector->dev, src_mode);
	if (!mode) {
		dev_err(panel->dev, "failed to add mode %ux%ux@%u\n",
			src_mode->hdisplay, src_mode->vdisplay,
			drm_mode_vrefresh(src_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.width_mm = 43;
	connector->display_info.height_mm = 57;

	drm_display_info_set_bus_formats(&connector->display_info,
					  &bus_format, 1);
	connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH |
					    DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;

	return 1;
}
static void LCD_Init(struct st7789v *ctx)
{
	st7789v_spi_idle(ctx);
	st7789v_write_command(ctx, 0x01);
	msleep(150);
	st7789v_write_command(ctx, 0x11);
	msleep(120);
	//--------------------------------Display and color format setting----------------------------//
	st7789v_write_command(ctx, 0x36);
	st7789v_write_data(ctx, 0x08);
	st7789v_write_command(ctx, 0x3a);
	st7789v_write_data(ctx, 0x06);

	st7789v_write_command(ctx, 0xB0);
	st7789v_write_data(ctx, 0x12); // 第1参数：RM=1, DM=01(RGB)
	st7789v_write_data(ctx, 0xC0); // 第2参数：EPF1 EPF0=11，其余控制位0

	st7789v_write_command(ctx, 0xB1);
	st7789v_write_data(ctx, 0x40);
	st7789v_write_data(ctx, 0x04);
	st7789v_write_data(ctx, 0x0a);
	//--------------------------------ST7789S Frame rate setting----------------------------------//
	st7789v_write_command(ctx, 0xb2);
	st7789v_write_data(ctx, 0x0c);
	st7789v_write_data(ctx, 0x0c);
	st7789v_write_data(ctx, 0x00);
	st7789v_write_data(ctx, 0x33);
	st7789v_write_data(ctx, 0x33);
	st7789v_write_command(ctx, 0xb7);
	st7789v_write_data(ctx, 0x35);
	//---------------------------------ST7789S Power setting--------------------------------------//
	st7789v_write_command(ctx, 0xbb);
	st7789v_write_data(ctx, 0x2b);
	st7789v_write_command(ctx, 0xc0);
	st7789v_write_data(ctx, 0x2c);
	st7789v_write_command(ctx, 0xc2);
	st7789v_write_data(ctx, 0x01);
	st7789v_write_command(ctx, 0xc3);
	st7789v_write_data(ctx, 0x11);
	st7789v_write_command(ctx, 0xc4);
	st7789v_write_data(ctx, 0x20);
	st7789v_write_command(ctx, 0xc6);
	st7789v_write_data(ctx, 0x0f);
	st7789v_write_command(ctx, 0xd0);
	st7789v_write_data(ctx, 0xa4);
	st7789v_write_data(ctx, 0xa1);
	//--------------------------------ST7789S gamma setting---------------------------------------//
	st7789v_write_command(ctx, 0xe0);
	st7789v_write_data(ctx, 0xd0);
	st7789v_write_data(ctx, 0x00);
	st7789v_write_data(ctx, 0x06);
	st7789v_write_data(ctx, 0x09);
	st7789v_write_data(ctx, 0x0b);
	st7789v_write_data(ctx, 0x2a);
	st7789v_write_data(ctx, 0x3c);
	st7789v_write_data(ctx, 0x55);
	st7789v_write_data(ctx, 0x4b);
	st7789v_write_data(ctx, 0x08);
	st7789v_write_data(ctx, 0x16);
	st7789v_write_data(ctx, 0x14);
	st7789v_write_data(ctx, 0x19);
	st7789v_write_data(ctx, 0x20);

	st7789v_write_command(ctx, 0xe1);
	st7789v_write_data(ctx, 0xd0);
	st7789v_write_data(ctx, 0x00);
	st7789v_write_data(ctx, 0x06);
	st7789v_write_data(ctx, 0x09);
	st7789v_write_data(ctx, 0x0b);
	st7789v_write_data(ctx, 0x29);
	st7789v_write_data(ctx, 0x36);
	st7789v_write_data(ctx, 0x54);
	st7789v_write_data(ctx, 0x4b);
	st7789v_write_data(ctx, 0x0d);
	st7789v_write_data(ctx, 0x16);
	st7789v_write_data(ctx, 0x14);
	st7789v_write_data(ctx, 0x21);
	st7789v_write_data(ctx, 0x20);
}

static int st7789v_prepare(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	int ret;

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

	gpiod_set_value_cansleep(ctx->reset, 1);
	msleep(50);
	gpiod_set_value_cansleep(ctx->reset, 0);
	msleep(50);
	st7789v_spi_idle(ctx);
	msleep(150);

	LCD_Init(ctx);

	return 0;
}

static int st7789v_enable(struct drm_panel *panel)
{
	struct st7789v *ctx = panel_to_st7789v(panel);
	msleep(20); // 等待第一帧脏画面刷新完毕
	st7789v_write_command(ctx, 0x29);
	msleep(50);
	return 0;
}

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

	st7789v_write_command(ctx, 0x28);

	return 0;
}

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

	st7789v_write_command(ctx, 0x10);
	msleep(120);
	gpiod_set_value_cansleep(ctx->reset, 1);
	st7789v_spi_idle(ctx);

	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,
	.prepare	= st7789v_prepare,
	.unprepare	= st7789v_unprepare,
};

static int st7789v_probe(struct spi_device *spi)
{
	struct st7789v *ctx;
	int ret;

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

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

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

	ctx->power = devm_regulator_get(&spi->dev, "power");
	if (IS_ERR(ctx->power))
		return PTR_ERR(ctx->power);

	ctx->reset = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(ctx->reset)) {
		dev_err(&spi->dev, "Couldn't get our reset line\n");
		return PTR_ERR(ctx->reset);
	}

	ctx->sclk = devm_gpiod_get(&spi->dev, "spi-scl", GPIOD_OUT_LOW);
	if (IS_ERR(ctx->sclk))
		return PTR_ERR(ctx->sclk);
	ctx->mosi = devm_gpiod_get(&spi->dev, "spi-sdi", GPIOD_OUT_LOW);
	if (IS_ERR(ctx->mosi))
		return PTR_ERR(ctx->mosi);
	ctx->cs = devm_gpiod_get(&spi->dev, "spi-cs", GPIOD_OUT_HIGH);
	if (IS_ERR(ctx->cs))
		return PTR_ERR(ctx->cs);

	st7789v_spi_idle(ctx);

	ret = drm_panel_of_backlight(&ctx->panel);
	if (ret)
		return ret;

	drm_panel_add(&ctx->panel);

	return 0;
}

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

	drm_panel_remove(&ctx->panel);

	return 0;
}

static const struct of_device_id st7789v_of_match[] = {
	{ .compatible = "lh,lh24030c50" },
	{ }
};
MODULE_DEVICE_TABLE(of, st7789v_of_match);

static struct spi_driver st7789v_driver = {
	.probe = st7789v_probe,
	.remove = st7789v_remove,
	.driver = {
		.name = "lh24030c50",
		.of_match_table = st7789v_of_match,
	},
};
module_spi_driver(st7789v_driver);

MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_DESCRIPTION("LH24030C50 RGB LCD panel driver");
MODULE_LICENSE("GPL v2");