text: /*
   * Copyright (C) 2017 Free Electrons
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation.
   */
  
  #include <linux/gpio/consumer.h>
  #include <linux/regulator/consumer.h>
  #include <linux/spi/spi.h>
  
  #include <drm/drmP.h>
  #include <drm/drm_panel.h>
  
  #include <video/mipi_display.h>
  
  #define ST7789V_COLMOD_RGB_FMT_18BITS		(6 << 4)
  #define ST7789V_COLMOD_CTRL_FMT_18BITS		(6 << 0)
  
  #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_HIGH		BIT(1)
  #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)
  
  struct st7789v {
  	struct drm_panel panel;
  	struct spi_device *spi;
  	struct gpio_desc *reset;
  	struct backlight_device *backlight;
  	struct regulator *power;
  };
  
  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 = { };
  	struct spi_message msg;
  	u16 txbuf = ((prefix & 1) << 8) | data;
  
  	spi_message_init(&msg);
  
  	xfer.tx_buf = &txbuf;
  	xfer.bits_per_word = 9;
  	xfer.len = sizeof(txbuf);
  
  	spi_message_add_tail(&xfer, &msg);
  	return spi_sync(ctx->spi, &msg);
  }
  
  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 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,
  	.vrefresh = 60,
  };
  
  static int st7789v_get_modes(struct drm_panel *panel)
  {
  	struct drm_connector *connector = panel->connector;
  	struct drm_display_mode *mode;
  
  	mode = drm_mode_duplicate(panel->drm, &default_mode);
  	if (!mode) {
  		dev_err(panel->drm->dev, "failed to add mode %ux%ux@%u\n",
  			default_mode.hdisplay, default_mode.vdisplay,
  			default_mode.vrefresh);
  		return -ENOMEM;
  	}
  
  	drm_mode_set_name(mode);
  
  	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
  	drm_mode_probed_add(connector, mode);
  
  	panel->connector->display_info.width_mm = 61;
  	panel->connector->display_info.height_mm = 103;
  
  	return 1;
  }
  
  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(ctx->reset, 1);
  	msleep(30);
  	gpiod_set_value(ctx->reset, 0);
  	msleep(120);
  
  	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,
  					     (MIPI_DCS_PIXEL_FMT_18BIT << 4) |
  					     (MIPI_DCS_PIXEL_FMT_18BIT)));
  
  	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)));
  
  	ST7789V_TEST(ret, st7789v_write_command(ctx, MIPI_DCS_ENTER_INVERT_MODE));
  
  	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, ST7789V_RGBCTRL_WO |
  					     ST7789V_RGBCTRL_RCM(2) |
  					     ST7789V_RGBCTRL_VSYNC_HIGH |
  					     ST7789V_RGBCTRL_HSYNC_HIGH |
  					     ST7789V_RGBCTRL_PCLK_HIGH));
  	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);
  
  	if (ctx->backlight) {
  		ctx->backlight->props.state &= ~BL_CORE_FBBLANK;
  		ctx->backlight->props.power = FB_BLANK_UNBLANK;
  		backlight_update_status(ctx->backlight);
  	}
  
  	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));
  
  	if (ctx->backlight) {
  		ctx->backlight->props.power = FB_BLANK_POWERDOWN;
  		ctx->backlight->props.state |= BL_CORE_FBBLANK;
  		backlight_update_status(ctx->backlight);
  	}
  
  	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,
  	.prepare	= st7789v_prepare,
  	.unprepare	= st7789v_unprepare,
  };
  
  static int st7789v_probe(struct spi_device *spi)
  {
  	struct device_node *backlight;
  	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;
  
  	ctx->panel.dev = &spi->dev;
  	ctx->panel.funcs = &st7789v_drm_funcs;
  
  	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_LOW);
  	if (IS_ERR(ctx->reset)) {
  		dev_err(&spi->dev, "Couldn't get our reset line\n");
  		return PTR_ERR(ctx->reset);
  	}
  
  	backlight = of_parse_phandle(spi->dev.of_node, "backlight", 0);
  	if (backlight) {
  		ctx->backlight = of_find_backlight_by_node(backlight);
  		of_node_put(backlight);
  
  		if (!ctx->backlight)
  			return -EPROBE_DEFER;
  	}
  
  	ret = drm_panel_add(&ctx->panel);
  	if (ret < 0)
  		goto err_free_backlight;
  
  	return 0;
  
  err_free_backlight:
  	if (ctx->backlight)
  		put_device(&ctx->backlight->dev);
  
  	return ret;
  }
  
  static int st7789v_remove(struct spi_device *spi)
  {
  	struct st7789v *ctx = spi_get_drvdata(spi);
  
  	drm_panel_detach(&ctx->panel);
  	drm_panel_remove(&ctx->panel);
  
  	if (ctx->backlight)
  		put_device(&ctx->backlight->dev);
  
  	return 0;
  }
  
  static const struct of_device_id st7789v_of_match[] = {
  	{ .compatible = "sitronix,st7789v" },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, st7789v_of_match);
  
  static struct spi_driver st7789v_driver = {
  	.probe = st7789v_probe,
  	.remove = st7789v_remove,
  	.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");
  