[PATCH v2 5/6] drm/sitronix/st7571: split up the driver into a common and an i2c part

[Marcus Folkesson <marcus.folkesson@gmail.com>]

Split up the driver to make it possible to add support for hw interfaces
other than I2C.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---
 MAINTAINERS                           |   1 +
 drivers/gpu/drm/sitronix/Kconfig      |  26 +-
 drivers/gpu/drm/sitronix/Makefile     |   1 +
 drivers/gpu/drm/sitronix/st7571-i2c.c | 925 +---------------------------------
 drivers/gpu/drm/sitronix/st7571.c     | 918 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/sitronix/st7571.h     |   6 +
 6 files changed, 960 insertions(+), 917 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 2814faae61eceecae1bccaaf92010e22dca81376..66e9ffb757c8bb19dbb894eb51f88f589ee83af6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8083,6 +8083,7 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/display/sitronix,st7567.yaml
 F:	Documentation/devicetree/bindings/display/sitronix,st7571.yaml
 F:	drivers/gpu/drm/sitronix/st7571-i2c.c
+F:	drivers/gpu/drm/sitronix/st7571.c
 F:	drivers/gpu/drm/sitronix/st7571.h
 
 DRM DRIVER FOR SITRONIX ST7701 PANELS
diff --git a/drivers/gpu/drm/sitronix/Kconfig b/drivers/gpu/drm/sitronix/Kconfig
index 6de7d92d9b74c72746915b945869dba91f161d2b..0676a86661caa4ab81f226ff2e990a3e2526f74d 100644
--- a/drivers/gpu/drm/sitronix/Kconfig
+++ b/drivers/gpu/drm/sitronix/Kconfig
@@ -1,13 +1,29 @@
-config DRM_ST7571_I2C
-	tristate "DRM support for Sitronix ST7571 display panels (I2C)"
-	depends on DRM && I2C && MMU
+config DRM_ST7571
+	tristate "DRM support for Sitronix ST7567/ST7571 display panels"
+	depends on DRM && MMU
 	select DRM_CLIENT_SELECTION
 	select DRM_GEM_SHMEM_HELPER
 	select DRM_KMS_HELPER
-	select REGMAP_I2C
 	select VIDEOMODE_HELPERS
 	help
-	  DRM driver for Sitronix ST7571 panels controlled over I2C.
+	  Sitronix ST7571 is a driver and controller for 4-level gray
+	  scale and monochrome dot matrix LCD panels.
+
+	  DRM driver for Sitronix ST7567/ST7571 panels.
+	  This is only the core driver, a driver for the appropriate bus
+	  transport in your chip also must be selected.
+
+	  if M is selected the module will be called st7571.
+
+config DRM_ST7571_I2C
+	tristate "DRM support for Sitronix ST7567/ST7571 display panels (I2C)"
+	depends on DRM_ST7571 && I2C
+	select REGMAP_I2C
+	help
+	  Sitronix ST7571 is a driver and controller for 4-level gray
+	  scale and monochrome dot matrix LCD panels.
+
+	  DRM driver for Sitronix ST7565/ST7571 panels connected via I2C bus.
 
 	  if M is selected the module will be called st7571-i2c.
 
diff --git a/drivers/gpu/drm/sitronix/Makefile b/drivers/gpu/drm/sitronix/Makefile
index bd139e5a6995fa026cc635b3c29782473d1efad7..8073bb776ff94de750f350b636fd9db3d54fdd46 100644
--- a/drivers/gpu/drm/sitronix/Makefile
+++ b/drivers/gpu/drm/sitronix/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_DRM_ST7571)		+= st7571.o
 obj-$(CONFIG_DRM_ST7571_I2C)		+= st7571-i2c.o
 obj-$(CONFIG_DRM_ST7586)		+= st7586.o
 obj-$(CONFIG_DRM_ST7735R)		+= st7735r.o
diff --git a/drivers/gpu/drm/sitronix/st7571-i2c.c b/drivers/gpu/drm/sitronix/st7571-i2c.c
index f994ace407390dba30c0968ca99f437382badfab..44bc94be33d6654e33688b0375bbac403b3d122f 100644
--- a/drivers/gpu/drm/sitronix/st7571-i2c.c
+++ b/drivers/gpu/drm/sitronix/st7571-i2c.c
@@ -1,85 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * Driver for Sitronix ST7571, a 4 level gray scale dot matrix LCD controller
+ * Driver for Sitronix ST7571 connected via I2C bus.
  *
  * Copyright (C) 2025 Marcus Folkesson <marcus.folkesson@gmail.com>
  */
 
-#include <linux/bitfield.h>
-#include <linux/delay.h>
-#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
 
-#include <drm/clients/drm_client_setup.h>
-#include <drm/drm_atomic.h>
-#include <drm/drm_atomic_helper.h>
-#include <drm/drm_connector.h>
-#include <drm/drm_crtc_helper.h>
-#include <drm/drm_damage_helper.h>
-#include <drm/drm_drv.h>
-#include <drm/drm_encoder.h>
-#include <drm/drm_fb_helper.h>
-#include <drm/drm_fbdev_shmem.h>
-#include <drm/drm_fourcc.h>
-#include <drm/drm_framebuffer.h>
-#include <drm/drm_gem_atomic_helper.h>
-#include <drm/drm_gem_framebuffer_helper.h>
-#include <drm/drm_gem_shmem_helper.h>
-#include <drm/drm_modeset_helper_vtables.h>
-#include <drm/drm_module.h>
-#include <drm/drm_plane.h>
-#include <drm/drm_probe_helper.h>
-
-#include <video/display_timing.h>
-#include <video/of_display_timing.h>
-
 #include "st7571.h"
 
-#define ST7571_COMMAND_MODE			(0x00)
-#define ST7571_DATA_MODE			(0x40)
-
-/* Normal mode command set */
-#define ST7571_DISPLAY_OFF			(0xae)
-#define ST7571_DISPLAY_ON			(0xaf)
-#define ST7571_OSC_ON				(0xab)
-#define ST7571_SET_COLUMN_LSB(c)		(0x00 | FIELD_PREP(GENMASK(3, 0), (c)))
-#define ST7571_SET_COLUMN_MSB(c)		(0x10 | FIELD_PREP(GENMASK(2, 0), (c) >> 4))
-#define ST7571_SET_COM0_LSB(x)			(FIELD_PREP(GENMASK(6, 0), (x)))
-#define ST7571_SET_COM0_MSB			(0x44)
-#define ST7571_SET_COM_SCAN_DIR(d)		(0xc0 | FIELD_PREP(GENMASK(3, 3), (d)))
-#define ST7571_SET_CONTRAST_LSB(c)		(FIELD_PREP(GENMASK(5, 0), (c)))
-#define ST7571_SET_CONTRAST_MSB			(0x81)
-#define ST7571_SET_DISPLAY_DUTY_LSB(d)		(FIELD_PREP(GENMASK(7, 0), (d)))
-#define ST7571_SET_DISPLAY_DUTY_MSB		(0x48)
-#define ST7571_SET_ENTIRE_DISPLAY_ON(p)		(0xa4 | FIELD_PREP(GENMASK(0, 0), (p)))
-#define ST7571_SET_LCD_BIAS(b)			(0x50 | FIELD_PREP(GENMASK(2, 0), (b)))
-#define ST7571_SET_MODE_LSB(m)			(FIELD_PREP(GENMASK(7, 2), (m)))
-#define ST7571_SET_MODE_MSB			(0x38)
-#define ST7571_SET_PAGE(p)			(0xb0 | FIELD_PREP(GENMASK(3, 0), (p)))
-#define ST7571_SET_POWER(p)			(0x28 | FIELD_PREP(GENMASK(2, 0), (p)))
-#define ST7571_SET_REGULATOR_REG(r)		(0x20 | FIELD_PREP(GENMASK(2, 0), (r)))
-#define ST7571_SET_REVERSE(r)			(0xa6 | FIELD_PREP(GENMASK(0, 0), (r)))
-#define ST7571_SET_SEG_SCAN_DIR(d)		(0xa0 | FIELD_PREP(GENMASK(0, 0), (d)))
-#define ST7571_SET_START_LINE_LSB(l)		(FIELD_PREP(GENMASK(6, 0), (l)))
-#define ST7571_SET_START_LINE_MSB		(0x40)
-
-/* Extension command set 3 */
-#define ST7571_COMMAND_SET_3			(0x7b)
-#define ST7571_SET_COLOR_MODE(c)		(0x10 | FIELD_PREP(GENMASK(0, 0), (c)))
-#define ST7571_COMMAND_SET_NORMAL		(0x00)
-
-/* ST7567 commands */
-#define ST7567_SET_LCD_BIAS(m) (0xa2 | FIELD_PREP(GENMASK(0, 0), (m)))
-
-#define ST7571_PAGE_HEIGHT 8
-
-#define DRIVER_NAME "st7571"
-#define DRIVER_DESC "ST7571 DRM driver"
-#define DRIVER_MAJOR 1
-#define DRIVER_MINOR 0
-
 struct st7571_i2c_transport {
 	struct i2c_client *client;
 
@@ -107,12 +38,7 @@ struct st7571_i2c_transport {
 	bool ignore_nak;
 };
 
-static inline struct st7571_device *drm_to_st7571(struct drm_device *drm)
-{
-	return container_of(drm, struct st7571_device, drm);
-}
-
-static int st7571_regmap_write(void *context, const void *data, size_t count)
+static int st7571_i2c_regmap_write(void *context, const void *data, size_t count)
 {
 	struct st7571_i2c_transport *t = context;
 	int ret;
@@ -139,825 +65,23 @@ static int st7571_regmap_write(void *context, const void *data, size_t count)
 }
 
 /* The st7571 driver does not read registers but regmap expects a .read */
-static int st7571_regmap_read(void *context, const void *reg_buf,
-			      size_t reg_size, void *val_buf, size_t val_size)
+static int st7571_i2c_regmap_read(void *context, const void *reg_buf,
+				  size_t reg_size, void *val_buf, size_t val_size)
 {
 	return -EOPNOTSUPP;
 }
 
-static int st7571_send_command_list(struct st7571_device *st7571,
-				    const u8 *cmd_list, size_t len)
-{
-	int ret;
-
-	for (int i = 0; i < len; i++) {
-		ret = regmap_write(st7571->regmap, ST7571_COMMAND_MODE, cmd_list[i]);
-		if (ret < 0)
-			return ret;
-	}
-
-	return ret;
-}
-
-static inline u8 st7571_transform_xy(const char *p, int x, int y, u8 bpp)
-{
-	int xrest = x % 8;
-	u8 result = 0;
-	u8 row_len = 16 * bpp;
-
-	/*
-	 * Transforms an (x, y) pixel coordinate into a vertical 8-bit
-	 * column from the framebuffer. It calculates the corresponding byte in the
-	 * framebuffer, extracts the bit at the given x position across 8 consecutive
-	 * rows, and packs those bits into a single byte.
-	 *
-	 * Return an 8-bit value representing a vertical column of pixels.
-	 */
-	x = x / 8;
-	y = (y / 8) * 8;
-
-	for (int i = 0; i < 8; i++) {
-		int row_idx = y + i;
-		u8 byte = p[row_idx * row_len + x];
-		u8 bit = (byte >> xrest) & 1;
-
-		result |= (bit << i);
-	}
-
-	return result;
-}
-
-static int st7571_set_position(struct st7571_device *st7571, int x, int y)
-{
-	u8 cmd_list[] = {
-		ST7571_SET_COLUMN_LSB(x),
-		ST7571_SET_COLUMN_MSB(x),
-		ST7571_SET_PAGE(y / ST7571_PAGE_HEIGHT),
-	};
-
-	return st7571_send_command_list(st7571, cmd_list, ARRAY_SIZE(cmd_list));
-}
-
-static int st7571_fb_clear_screen(struct st7571_device *st7571)
-{
-	u32 npixels = st7571->ncols * round_up(st7571->nlines, ST7571_PAGE_HEIGHT) * st7571->bpp;
-	char pixelvalue = 0x00;
-
-	st7571_set_position(st7571, 0, 0);
-	for (int i = 0; i < npixels; i++)
-		regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, &pixelvalue, 1);
-
-	return 0;
-}
-
-static void st7571_prepare_buffer_monochrome(struct st7571_device *st7571,
-					     const struct iosys_map *vmap,
-					     struct drm_framebuffer *fb,
-					     struct drm_rect *rect,
-					     struct drm_format_conv_state *fmtcnv_state)
-{
-	unsigned int dst_pitch;
-	struct iosys_map dst;
-	u32 size;
-
-	switch (fb->format->format) {
-	case DRM_FORMAT_XRGB8888:
-		dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 8);
-		iosys_map_set_vaddr(&dst, st7571->hwbuf);
-
-		drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, vmap, fb, rect, fmtcnv_state);
-		break;
-
-	case DRM_FORMAT_R1:
-		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
-		memcpy(st7571->hwbuf, vmap->vaddr, size);
-		break;
-	}
-}
-
-static void st7571_prepare_buffer_grayscale(struct st7571_device *st7571,
-					    const struct iosys_map *vmap,
-					    struct drm_framebuffer *fb,
-					    struct drm_rect *rect,
-					    struct drm_format_conv_state *fmtcnv_state)
-{
-	u32 size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
-	unsigned int dst_pitch;
-	struct iosys_map dst;
-
-	switch (fb->format->format) {
-	case DRM_FORMAT_XRGB8888:
-		dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 4);
-		iosys_map_set_vaddr(&dst, st7571->hwbuf);
-
-		drm_fb_xrgb8888_to_gray2(&dst, &dst_pitch, vmap, fb, rect, fmtcnv_state);
-		break;
-
-	case DRM_FORMAT_R1:
-		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
-		memcpy(st7571->hwbuf, vmap->vaddr, size);
-		break;
-
-	case DRM_FORMAT_R2:
-		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 4;
-		memcpy(st7571->hwbuf, vmap->vaddr, size);
-		break;
-	}
-}
-
-static int st7571_fb_update_rect_monochrome(struct drm_framebuffer *fb, struct drm_rect *rect)
-{
-	struct st7571_device *st7571 = drm_to_st7571(fb->dev);
-	char *row = st7571->row;
-
-	/* Align y to display page boundaries */
-	rect->y1 = round_down(rect->y1, ST7571_PAGE_HEIGHT);
-	rect->y2 = min_t(unsigned int, round_up(rect->y2, ST7571_PAGE_HEIGHT), st7571->nlines);
-
-	for (int y = rect->y1; y < rect->y2; y += ST7571_PAGE_HEIGHT) {
-		for (int x = rect->x1; x < rect->x2; x++)
-			row[x] = st7571_transform_xy(st7571->hwbuf, x, y, 1);
-
-		st7571_set_position(st7571, rect->x1, y);
-
-		/* TODO: Investige why we can't write multiple bytes at once */
-		for (int x = rect->x1; x < rect->x2; x++)
-			regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
-	}
-
-	return 0;
-}
-
-static int st7571_fb_update_rect_grayscale(struct drm_framebuffer *fb, struct drm_rect *rect)
-{
-	struct st7571_device *st7571 = drm_to_st7571(fb->dev);
-	u32 format = fb->format->format;
-	char *row = st7571->row;
-	int x1;
-	int x2;
-
-	/* Align y to display page boundaries */
-	rect->y1 = round_down(rect->y1, ST7571_PAGE_HEIGHT);
-	rect->y2 = min_t(unsigned int, round_up(rect->y2, ST7571_PAGE_HEIGHT), st7571->nlines);
-
-	switch (format) {
-	case DRM_FORMAT_R1:
-		x1 = rect->x1 * 1;
-		x2 = rect->x2 * 1;
-		break;
-	case DRM_FORMAT_R2:
-		fallthrough;
-	case DRM_FORMAT_XRGB8888:
-		x1 = rect->x1 * 2;
-		x2 = rect->x2 * 2;
-		break;
-	}
-
-	for (int y = rect->y1; y < rect->y2; y += ST7571_PAGE_HEIGHT) {
-		for (int x = x1; x < x2; x++)
-			row[x] = st7571_transform_xy(st7571->hwbuf, x, y, 2);
-
-		st7571_set_position(st7571, rect->x1, y);
-
-		/* TODO: Investige why we can't write multiple bytes at once */
-		for (int x = x1; x < x2; x++) {
-			regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
-
-			/*
-			 * As the display supports grayscale, all pixels must be written as two bits
-			 * even if the format is monochrome.
-			 *
-			 * The bit values maps to the following grayscale:
-			 * 0 0 = Black
-			 * 0 1 = Dark gray
-			 * 1 0 = Light gray
-			 * 1 1 = White
-			 *
-			 * For monochrome formats, write the same value twice to get
-			 * either a black or white pixel.
-			 */
-			if (format == DRM_FORMAT_R1)
-				regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
-		}
-	}
-
-	return 0;
-}
-
-static int st7571_connector_get_modes(struct drm_connector *conn)
-{
-	struct st7571_device *st7571 = drm_to_st7571(conn->dev);
-
-	return drm_connector_helper_get_modes_fixed(conn, &st7571->mode);
-}
-
-static const struct drm_connector_helper_funcs st7571_connector_helper_funcs = {
-	.get_modes = st7571_connector_get_modes,
-};
-
-static const struct st7571_panel_format st7571_monochrome = {
-	.prepare_buffer = st7571_prepare_buffer_monochrome,
-	.update_rect = st7571_fb_update_rect_monochrome,
-	.mode = ST7571_COLOR_MODE_BLACKWHITE,
-	.formats = {
-		DRM_FORMAT_XRGB8888,
-		DRM_FORMAT_R1,
-	},
-	.nformats = 2,
-};
-
-static const struct st7571_panel_format st7571_grayscale = {
-	.prepare_buffer = st7571_prepare_buffer_grayscale,
-	.update_rect = st7571_fb_update_rect_grayscale,
-	.mode = ST7571_COLOR_MODE_GRAY,
-	.formats = {
-		DRM_FORMAT_XRGB8888,
-		DRM_FORMAT_R1,
-		DRM_FORMAT_R2,
-	},
-	.nformats = 3,
-};
-
-static const u64 st7571_primary_plane_fmtmods[] = {
-	DRM_FORMAT_MOD_LINEAR,
-	DRM_FORMAT_MOD_INVALID
-};
-
-static int st7571_primary_plane_helper_atomic_check(struct drm_plane *plane,
-						    struct drm_atomic_state *state)
-{
-	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_crtc *new_crtc = new_plane_state->crtc;
-	struct drm_crtc_state *new_crtc_state = NULL;
-
-	if (new_crtc)
-		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
-
-	return drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
-						   DRM_PLANE_NO_SCALING,
-						   DRM_PLANE_NO_SCALING,
-						   false, false);
-}
-
-static void st7571_primary_plane_helper_atomic_update(struct drm_plane *plane,
-						      struct drm_atomic_state *state)
-{
-	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
-	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
-	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
-	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_atomic_helper_damage_iter iter;
-	struct drm_device *drm = plane->dev;
-	struct drm_rect damage;
-	struct st7571_device *st7571 = drm_to_st7571(plane->dev);
-	int ret, idx;
-
-	if (!fb)
-		return; /* no framebuffer; plane is disabled */
-
-	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
-	if (ret)
-		return;
-
-	if (!drm_dev_enter(drm, &idx))
-		goto out_drm_gem_fb_end_cpu_access;
-
-	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
-	drm_atomic_for_each_plane_damage(&iter, &damage) {
-		st7571->pformat->prepare_buffer(st7571,
-						&shadow_plane_state->data[0],
-						fb, &damage,
-						&shadow_plane_state->fmtcnv_state);
-
-		st7571->pformat->update_rect(fb, &damage);
-	}
-
-	drm_dev_exit(idx);
-
-out_drm_gem_fb_end_cpu_access:
-	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
-}
-
-static void st7571_primary_plane_helper_atomic_disable(struct drm_plane *plane,
-						       struct drm_atomic_state *state)
-{
-	struct drm_device *drm = plane->dev;
-	struct st7571_device *st7571 = drm_to_st7571(plane->dev);
-	int idx;
-
-	if (!drm_dev_enter(drm, &idx))
-		return;
-
-	st7571_fb_clear_screen(st7571);
-	drm_dev_exit(idx);
-}
-
-static const struct drm_plane_helper_funcs st7571_primary_plane_helper_funcs = {
-	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
-	.atomic_check = st7571_primary_plane_helper_atomic_check,
-	.atomic_update = st7571_primary_plane_helper_atomic_update,
-	.atomic_disable = st7571_primary_plane_helper_atomic_disable,
-};
-
-static const struct drm_plane_funcs st7571_primary_plane_funcs = {
-	.update_plane = drm_atomic_helper_update_plane,
-	.disable_plane = drm_atomic_helper_disable_plane,
-	.destroy = drm_plane_cleanup,
-	DRM_GEM_SHADOW_PLANE_FUNCS,
-};
-
-/*
- * CRTC
- */
-
-static enum drm_mode_status st7571_crtc_mode_valid(struct drm_crtc *crtc,
-						   const struct drm_display_mode *mode)
-{
-	struct st7571_device *st7571 = drm_to_st7571(crtc->dev);
-
-	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &st7571->mode);
-}
-
-static const struct drm_crtc_helper_funcs st7571_crtc_helper_funcs = {
-	.atomic_check = drm_crtc_helper_atomic_check,
-	.mode_valid = st7571_crtc_mode_valid,
-};
-
-static const struct drm_crtc_funcs st7571_crtc_funcs = {
-	.reset = drm_atomic_helper_crtc_reset,
-	.destroy = drm_crtc_cleanup,
-	.set_config = drm_atomic_helper_set_config,
-	.page_flip = drm_atomic_helper_page_flip,
-	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
-};
-
-/*
- * Encoder
- */
-
-static void st7571_encoder_atomic_enable(struct drm_encoder *encoder,
-					 struct drm_atomic_state *state)
-{
-	struct drm_device *drm = encoder->dev;
-	struct st7571_device *st7571 = drm_to_st7571(drm);
-	u8 command = ST7571_DISPLAY_ON;
-	int ret;
-
-	ret = st7571->pdata->init(st7571);
-	if (ret)
-		return;
-
-	st7571_send_command_list(st7571, &command, 1);
-}
-
-static void st7571_encoder_atomic_disable(struct drm_encoder *encoder,
-					  struct drm_atomic_state *state)
-{
-	struct drm_device *drm = encoder->dev;
-	struct st7571_device *st7571 = drm_to_st7571(drm);
-	u8 command = ST7571_DISPLAY_OFF;
-
-	st7571_send_command_list(st7571, &command, 1);
-}
-
-static const struct drm_encoder_funcs st7571_encoder_funcs = {
-	.destroy = drm_encoder_cleanup,
-
-};
-
-static const struct drm_encoder_helper_funcs st7571_encoder_helper_funcs = {
-	.atomic_enable = st7571_encoder_atomic_enable,
-	.atomic_disable = st7571_encoder_atomic_disable,
-};
-
-/*
- * Connector
- */
-
-static const struct drm_connector_funcs st7571_connector_funcs = {
-	.reset = drm_atomic_helper_connector_reset,
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = drm_connector_cleanup,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static const struct drm_mode_config_funcs st7571_mode_config_funcs = {
-	.fb_create = drm_gem_fb_create_with_dirty,
-	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = drm_atomic_helper_commit,
+static const struct regmap_bus st7571_i2c_regmap_bus = {
+	.read = st7571_i2c_regmap_read,
+	.write = st7571_i2c_regmap_write,
 };
 
-static struct drm_display_mode st7571_mode(struct st7571_device *st7571)
-{
-	struct drm_display_mode mode = {
-		DRM_SIMPLE_MODE(st7571->ncols, st7571->nlines,
-				st7571->width_mm, st7571->height_mm),
-	};
-
-	return mode;
-}
-
-static int st7571_mode_config_init(struct st7571_device *st7571)
-{
-	struct drm_device *drm = &st7571->drm;
-	const struct st7571_panel_constraints *constraints = &st7571->pdata->constraints;
-	int ret;
-
-	ret = drmm_mode_config_init(drm);
-	if (ret)
-		return ret;
-
-	drm->mode_config.min_width = constraints->min_ncols;
-	drm->mode_config.min_height = constraints->min_nlines;
-	drm->mode_config.max_width = constraints->max_ncols;
-	drm->mode_config.max_height = constraints->max_nlines;
-	drm->mode_config.preferred_depth = 24;
-	drm->mode_config.funcs = &st7571_mode_config_funcs;
-
-	return 0;
-}
-
-static int st7571_plane_init(struct st7571_device *st7571,
-			     const struct st7571_panel_format *pformat)
-{
-	struct drm_plane *primary_plane = &st7571->primary_plane;
-	struct drm_device *drm = &st7571->drm;
-	int ret;
-
-	ret = drm_universal_plane_init(drm, primary_plane, 0,
-				       &st7571_primary_plane_funcs,
-				       pformat->formats,
-				       pformat->nformats,
-				       st7571_primary_plane_fmtmods,
-				       DRM_PLANE_TYPE_PRIMARY, NULL);
-	if (ret)
-		return ret;
-
-	drm_plane_helper_add(primary_plane, &st7571_primary_plane_helper_funcs);
-	drm_plane_enable_fb_damage_clips(primary_plane);
-
-	return 0;
-}
-
-static int st7571_crtc_init(struct st7571_device *st7571)
-{
-	struct drm_plane *primary_plane = &st7571->primary_plane;
-	struct drm_crtc *crtc = &st7571->crtc;
-	struct drm_device *drm = &st7571->drm;
-	int ret;
-
-	ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
-					&st7571_crtc_funcs, NULL);
-	if (ret)
-		return ret;
-
-	drm_crtc_helper_add(crtc, &st7571_crtc_helper_funcs);
-
-	return 0;
-}
-
-static int st7571_encoder_init(struct st7571_device *st7571)
-{
-	struct drm_encoder *encoder = &st7571->encoder;
-	struct drm_crtc *crtc = &st7571->crtc;
-	struct drm_device *drm = &st7571->drm;
-	int ret;
-
-	ret = drm_encoder_init(drm, encoder, &st7571_encoder_funcs, DRM_MODE_ENCODER_NONE, NULL);
-	if (ret)
-		return ret;
-
-	drm_encoder_helper_add(encoder, &st7571_encoder_helper_funcs);
-
-	encoder->possible_crtcs = drm_crtc_mask(crtc);
-
-	return 0;
-}
-
-static int st7571_connector_init(struct st7571_device *st7571)
-{
-	struct drm_connector *connector = &st7571->connector;
-	struct drm_encoder *encoder = &st7571->encoder;
-	struct drm_device *drm = &st7571->drm;
-	int ret;
-
-	ret = drm_connector_init(drm, connector, &st7571_connector_funcs,
-				 DRM_MODE_CONNECTOR_Unknown);
-	if (ret)
-		return ret;
-
-	drm_connector_helper_add(connector, &st7571_connector_helper_funcs);
-
-	return drm_connector_attach_encoder(connector, encoder);
-}
-
-DEFINE_DRM_GEM_FOPS(st7571_fops);
-
-static const struct drm_driver st7571_driver = {
-	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
-
-	.name		 = DRIVER_NAME,
-	.desc		 = DRIVER_DESC,
-	.major		 = DRIVER_MAJOR,
-	.minor		 = DRIVER_MINOR,
-
-	.fops		 = &st7571_fops,
-	DRM_GEM_SHMEM_DRIVER_OPS,
-	DRM_FBDEV_SHMEM_DRIVER_OPS,
-};
-
-static const struct regmap_bus st7571_regmap_bus = {
-	.read = st7571_regmap_read,
-	.write = st7571_regmap_write,
-};
-
-static const struct regmap_config st7571_regmap_config = {
+static const struct regmap_config st7571_i2c_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.use_single_write = true,
 };
 
-static int st7571_validate_parameters(struct st7571_device *st7571)
-{
-	struct device *dev = st7571->dev;
-	const struct st7571_panel_constraints *constraints = &st7571->pdata->constraints;
-
-	if (st7571->width_mm  == 0) {
-		dev_err(dev, "Invalid panel width\n");
-		return -EINVAL;
-	}
-
-	if (st7571->height_mm == 0) {
-		dev_err(dev, "Invalid panel height\n");
-		return -EINVAL;
-	}
-
-	if (st7571->nlines < constraints->min_nlines ||
-	    st7571->nlines > constraints->max_nlines) {
-		dev_err(dev, "Invalid timing configuration.\n");
-		return -EINVAL;
-	}
-
-	if (st7571->startline + st7571->nlines > constraints->max_nlines) {
-		dev_err(dev, "Invalid timing configuration.\n");
-		return -EINVAL;
-	}
-
-	if (st7571->ncols < constraints->min_ncols ||
-	    st7571->ncols > constraints->max_ncols) {
-		dev_err(dev, "Invalid timing configuration.\n");
-		return -EINVAL;
-	}
-
-	if (st7571->grayscale && !constraints->support_grayscale) {
-		dev_err(dev, "Grayscale not supported\n");
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static int st7567_parse_dt(struct st7571_device *st7567)
-{
-	struct device *dev = st7567->dev;
-	struct device_node *np = dev->of_node;
-	struct display_timing dt;
-	int ret;
-
-	ret = of_get_display_timing(np, "panel-timing", &dt);
-	if (ret) {
-		dev_err(dev, "Failed to get display timing from DT\n");
-		return ret;
-	}
-
-	of_property_read_u32(np, "width-mm", &st7567->width_mm);
-	of_property_read_u32(np, "height-mm", &st7567->height_mm);
-	st7567->inverted = of_property_read_bool(np, "sitronix,inverted");
-
-	st7567->pformat = &st7571_monochrome;
-	st7567->bpp = 1;
-
-	st7567->startline = dt.vfront_porch.typ;
-	st7567->nlines = dt.vactive.typ;
-	st7567->ncols = dt.hactive.typ;
-
-	return 0;
-}
-
-static int st7571_parse_dt(struct st7571_device *st7571)
-{
-	struct device *dev = st7571->dev;
-	struct device_node *np = dev->of_node;
-	struct display_timing dt;
-	int ret;
-
-	ret = of_get_display_timing(np, "panel-timing", &dt);
-	if (ret) {
-		dev_err(dev, "Failed to get display timing from DT\n");
-		return ret;
-	}
-
-	of_property_read_u32(np, "width-mm", &st7571->width_mm);
-	of_property_read_u32(np, "height-mm", &st7571->height_mm);
-	st7571->grayscale = of_property_read_bool(np, "sitronix,grayscale");
-	st7571->inverted = of_property_read_bool(np, "sitronix,inverted");
-
-	if (st7571->grayscale) {
-		st7571->pformat = &st7571_grayscale;
-		st7571->bpp = 2;
-	} else {
-		st7571->pformat = &st7571_monochrome;
-		st7571->bpp = 1;
-	}
-
-	st7571->startline = dt.vfront_porch.typ;
-	st7571->nlines = dt.vactive.typ;
-	st7571->ncols = dt.hactive.typ;
-
-	st7571->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
-	if (IS_ERR(st7571->reset))
-		return dev_err_probe(dev, PTR_ERR(st7571->reset),
-				     "Failed to get reset gpio\n");
-
-
-	return 0;
-}
-
-static void st7571_reset(struct st7571_device *st7571)
-{
-	gpiod_set_value_cansleep(st7571->reset, 1);
-	fsleep(20);
-	gpiod_set_value_cansleep(st7571->reset, 0);
-}
-
-static int st7567_lcd_init(struct st7571_device *st7567)
-{
-	/*
-	 * Most of the initialization sequence is taken directly from the
-	 * referential initial code in the ST7567 datasheet.
-	 */
-	u8 commands[] = {
-		ST7571_DISPLAY_OFF,
-
-		ST7567_SET_LCD_BIAS(1),
-
-		ST7571_SET_SEG_SCAN_DIR(0),
-		ST7571_SET_COM_SCAN_DIR(1),
-
-		ST7571_SET_REGULATOR_REG(4),
-		ST7571_SET_CONTRAST_MSB,
-		ST7571_SET_CONTRAST_LSB(0x20),
-
-		ST7571_SET_START_LINE_MSB,
-		ST7571_SET_START_LINE_LSB(st7567->startline),
-
-		ST7571_SET_POWER(0x4),	/* Power Control, VC: ON, VR: OFF, VF: OFF */
-		ST7571_SET_POWER(0x6),	/* Power Control, VC: ON, VR: ON, VF: OFF */
-		ST7571_SET_POWER(0x7),	/* Power Control, VC: ON, VR: ON, VF: ON */
-
-		ST7571_SET_REVERSE(st7567->inverted ? 1 : 0),
-		ST7571_SET_ENTIRE_DISPLAY_ON(0),
-	};
-
-	return st7571_send_command_list(st7567, commands, ARRAY_SIZE(commands));
-}
-
-static int st7571_lcd_init(struct st7571_device *st7571)
-{
-	/*
-	 * Most of the initialization sequence is taken directly from the
-	 * referential initial code in the ST7571 datasheet.
-	 */
-	u8 commands[] = {
-		ST7571_DISPLAY_OFF,
-
-		ST7571_SET_MODE_MSB,
-		ST7571_SET_MODE_LSB(0x2e),
-
-		ST7571_SET_SEG_SCAN_DIR(0),
-		ST7571_SET_COM_SCAN_DIR(1),
-
-		ST7571_SET_COM0_MSB,
-		ST7571_SET_COM0_LSB(0x00),
-
-		ST7571_SET_START_LINE_MSB,
-		ST7571_SET_START_LINE_LSB(st7571->startline),
-
-		ST7571_OSC_ON,
-		ST7571_SET_REGULATOR_REG(5),
-		ST7571_SET_CONTRAST_MSB,
-		ST7571_SET_CONTRAST_LSB(0x33),
-		ST7571_SET_LCD_BIAS(0x04),
-		ST7571_SET_DISPLAY_DUTY_MSB,
-		ST7571_SET_DISPLAY_DUTY_LSB(st7571->nlines),
-
-		ST7571_SET_POWER(0x4),	/* Power Control, VC: ON, VR: OFF, VF: OFF */
-		ST7571_SET_POWER(0x6),	/* Power Control, VC: ON, VR: ON, VF: OFF */
-		ST7571_SET_POWER(0x7),	/* Power Control, VC: ON, VR: ON, VF: ON */
-
-		ST7571_COMMAND_SET_3,
-		ST7571_SET_COLOR_MODE(st7571->pformat->mode),
-		ST7571_COMMAND_SET_NORMAL,
-
-		ST7571_SET_REVERSE(st7571->inverted ? 1 : 0),
-		ST7571_SET_ENTIRE_DISPLAY_ON(0),
-	};
-
-	/* Perform a reset before initializing the controller */
-	st7571_reset(st7571);
-
-	return st7571_send_command_list(st7571, commands, ARRAY_SIZE(commands));
-}
-
-static struct st7571_device *st7571_probe(struct device *dev,
-					  struct regmap *regmap)
-{
-	struct st7571_device *st7571;
-	struct drm_device *drm;
-	int ret;
-
-	st7571 = devm_drm_dev_alloc(dev, &st7571_driver,
-				    struct st7571_device, drm);
-	if (IS_ERR(st7571))
-		return st7571;
-
-	drm = &st7571->drm;
-	st7571->dev = dev;
-	st7571->pdata = device_get_match_data(st7571->dev);
-
-	ret = st7571->pdata->parse_dt(st7571);
-	if (ret)
-		return ERR_PTR(ret);
-
-	ret = st7571_validate_parameters(st7571);
-	if (ret)
-		return ERR_PTR(ret);
-
-	st7571->mode = st7571_mode(st7571);
-	st7571->regmap = regmap;
-
-
-	st7571->hwbuf = devm_kzalloc(st7571->dev,
-				     (st7571->nlines * st7571->ncols * st7571->bpp) / 8,
-				     GFP_KERNEL);
-	if (!st7571->hwbuf)
-		return ERR_PTR(-ENOMEM);
-
-	st7571->row = devm_kzalloc(st7571->dev,
-				   (st7571->ncols * st7571->bpp),
-				   GFP_KERNEL);
-	if (!st7571->row)
-		return ERR_PTR(-ENOMEM);
-
-	ret = st7571_mode_config_init(st7571);
-	if (ret) {
-		dev_err(st7571->dev, "Failed to initialize mode config\n");
-		return ERR_PTR(ret);
-	}
-
-	ret = st7571_plane_init(st7571, st7571->pformat);
-	if (ret) {
-		dev_err(st7571->dev, "Failed to initialize primary plane\n");
-		return ERR_PTR(ret);
-	}
-
-	ret = st7571_crtc_init(st7571);
-	if (ret < 0) {
-		dev_err(st7571->dev, "Failed to initialize CRTC\n");
-		return ERR_PTR(ret);
-	}
-
-	ret = st7571_encoder_init(st7571);
-	if (ret < 0) {
-		dev_err(st7571->dev, "Failed to initialize encoder\n");
-		return ERR_PTR(ret);
-	}
-
-	ret = st7571_connector_init(st7571);
-	if (ret < 0) {
-		dev_err(st7571->dev, "Failed to initialize connector\n");
-		return ERR_PTR(ret);
-	}
-
-	drm_mode_config_reset(drm);
-
-	ret = drm_dev_register(drm, 0);
-	if (ret) {
-		dev_err(st7571->dev, "Failed to register DRM device\n");
-		return ERR_PTR(ret);
-	}
-
-	drm_client_setup(drm, NULL);
-	return st7571;
-}
-
-static void st7571_remove(struct st7571_device *st7571)
-{
-	drm_dev_unplug(&st7571->drm);
-}
-
 static int st7571_i2c_probe(struct i2c_client *client)
 {
 	struct st7571_device *st7571;
@@ -979,8 +103,8 @@ static int st7571_i2c_probe(struct i2c_client *client)
 	if (i2c_check_functionality(client->adapter, I2C_FUNC_PROTOCOL_MANGLING))
 		t->ignore_nak = true;
 
-	regmap = devm_regmap_init(&client->dev, &st7571_regmap_bus,
-				  t, &st7571_regmap_config);
+	regmap = devm_regmap_init(&client->dev, &st7571_i2c_regmap_bus,
+				  t, &st7571_i2c_regmap_config);
 	if (IS_ERR(regmap)) {
 		return dev_err_probe(&client->dev, PTR_ERR(regmap),
 				     "Failed to initialize regmap\n");
@@ -1002,30 +126,6 @@ static void st7571_i2c_remove(struct i2c_client *client)
 	st7571_remove(st7571);
 }
 
-static const struct st7571_panel_data st7567_config = {
-	.init = st7567_lcd_init,
-	.parse_dt = st7567_parse_dt,
-	.constraints = {
-		.min_nlines = 1,
-		.max_nlines = 64,
-		.min_ncols = 128,
-		.max_ncols = 128,
-		.support_grayscale = false,
-	},
-};
-
-static const struct st7571_panel_data st7571_config = {
-	.init = st7571_lcd_init,
-	.parse_dt = st7571_parse_dt,
-	.constraints = {
-		.min_nlines = 1,
-		.max_nlines = 128,
-		.min_ncols = 128,
-		.max_ncols = 128,
-		.support_grayscale = true,
-	},
-};
-
 static const struct of_device_id st7571_of_match[] = {
 	{ .compatible = "sitronix,st7567", .data = &st7567_config },
 	{ .compatible = "sitronix,st7571", .data = &st7571_config },
@@ -1042,7 +142,7 @@ MODULE_DEVICE_TABLE(i2c, st7571_id);
 
 static struct i2c_driver st7571_i2c_driver = {
 	.driver = {
-		.name = "st7571",
+		.name = "st7571-i2c",
 		.of_match_table = st7571_of_match,
 	},
 	.probe = st7571_i2c_probe,
@@ -1053,5 +153,6 @@ static struct i2c_driver st7571_i2c_driver = {
 module_i2c_driver(st7571_i2c_driver);
 
 MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
-MODULE_DESCRIPTION("DRM Driver for Sitronix ST7571 LCD controller");
+MODULE_DESCRIPTION("DRM Driver for Sitronix ST7571 LCD controller (I2C)");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("DRM_ST7571");
diff --git a/drivers/gpu/drm/sitronix/st7571.c b/drivers/gpu/drm/sitronix/st7571.c
new file mode 100644
index 0000000000000000000000000000000000000000..5fd575d972a2e3b6654af7ed0a4ab5c4323e7a33
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7571.c
@@ -0,0 +1,918 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Sitronix ST7571, a 4 level gray scale dot matrix LCD controller
+ *
+ * Copyright (C) 2025 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include <drm/clients/drm_client_setup.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_fbdev_shmem.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_module.h>
+#include <drm/drm_plane.h>
+#include <drm/drm_probe_helper.h>
+
+#include <video/display_timing.h>
+#include <video/of_display_timing.h>
+
+#include "st7571.h"
+
+#define ST7571_COMMAND_MODE			(0x00)
+#define ST7571_DATA_MODE			(0x40)
+
+/* Normal mode command set */
+#define ST7571_DISPLAY_OFF			(0xae)
+#define ST7571_DISPLAY_ON			(0xaf)
+#define ST7571_OSC_ON				(0xab)
+#define ST7571_SET_COLUMN_LSB(c)		(0x00 | FIELD_PREP(GENMASK(3, 0), (c)))
+#define ST7571_SET_COLUMN_MSB(c)		(0x10 | FIELD_PREP(GENMASK(2, 0), (c) >> 4))
+#define ST7571_SET_COM0_LSB(x)			(FIELD_PREP(GENMASK(6, 0), (x)))
+#define ST7571_SET_COM0_MSB			(0x44)
+#define ST7571_SET_COM_SCAN_DIR(d)		(0xc0 | FIELD_PREP(GENMASK(3, 3), (d)))
+#define ST7571_SET_CONTRAST_LSB(c)		(FIELD_PREP(GENMASK(5, 0), (c)))
+#define ST7571_SET_CONTRAST_MSB			(0x81)
+#define ST7571_SET_DISPLAY_DUTY_LSB(d)		(FIELD_PREP(GENMASK(7, 0), (d)))
+#define ST7571_SET_DISPLAY_DUTY_MSB		(0x48)
+#define ST7571_SET_ENTIRE_DISPLAY_ON(p)		(0xa4 | FIELD_PREP(GENMASK(0, 0), (p)))
+#define ST7571_SET_LCD_BIAS(b)			(0x50 | FIELD_PREP(GENMASK(2, 0), (b)))
+#define ST7571_SET_MODE_LSB(m)			(FIELD_PREP(GENMASK(7, 2), (m)))
+#define ST7571_SET_MODE_MSB			(0x38)
+#define ST7571_SET_PAGE(p)			(0xb0 | FIELD_PREP(GENMASK(3, 0), (p)))
+#define ST7571_SET_POWER(p)			(0x28 | FIELD_PREP(GENMASK(2, 0), (p)))
+#define ST7571_SET_REGULATOR_REG(r)		(0x20 | FIELD_PREP(GENMASK(2, 0), (r)))
+#define ST7571_SET_REVERSE(r)			(0xa6 | FIELD_PREP(GENMASK(0, 0), (r)))
+#define ST7571_SET_SEG_SCAN_DIR(d)		(0xa0 | FIELD_PREP(GENMASK(0, 0), (d)))
+#define ST7571_SET_START_LINE_LSB(l)		(FIELD_PREP(GENMASK(6, 0), (l)))
+#define ST7571_SET_START_LINE_MSB		(0x40)
+
+/* Extension command set 3 */
+#define ST7571_COMMAND_SET_3			(0x7b)
+#define ST7571_SET_COLOR_MODE(c)		(0x10 | FIELD_PREP(GENMASK(0, 0), (c)))
+#define ST7571_COMMAND_SET_NORMAL		(0x00)
+
+/* ST7567 commands */
+#define ST7567_SET_LCD_BIAS(m) (0xa2 | FIELD_PREP(GENMASK(0, 0), (m)))
+
+#define ST7571_PAGE_HEIGHT 8
+
+#define DRIVER_NAME "st7571"
+#define DRIVER_DESC "ST7571 DRM driver"
+#define DRIVER_MAJOR 1
+#define DRIVER_MINOR 0
+
+static inline struct st7571_device *drm_to_st7571(struct drm_device *drm)
+{
+	return container_of(drm, struct st7571_device, drm);
+}
+
+static int st7571_send_command_list(struct st7571_device *st7571,
+				    const u8 *cmd_list, size_t len)
+{
+	int ret;
+
+	for (int i = 0; i < len; i++) {
+		ret = regmap_write(st7571->regmap, ST7571_COMMAND_MODE, cmd_list[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+}
+
+static inline u8 st7571_transform_xy(const char *p, int x, int y, u8 bpp)
+{
+	int xrest = x % 8;
+	u8 result = 0;
+	u8 row_len = 16 * bpp;
+
+	/*
+	 * Transforms an (x, y) pixel coordinate into a vertical 8-bit
+	 * column from the framebuffer. It calculates the corresponding byte in the
+	 * framebuffer, extracts the bit at the given x position across 8 consecutive
+	 * rows, and packs those bits into a single byte.
+	 *
+	 * Return an 8-bit value representing a vertical column of pixels.
+	 */
+	x = x / 8;
+	y = (y / 8) * 8;
+
+	for (int i = 0; i < 8; i++) {
+		int row_idx = y + i;
+		u8 byte = p[row_idx * row_len + x];
+		u8 bit = (byte >> xrest) & 1;
+
+		result |= (bit << i);
+	}
+
+	return result;
+}
+
+static int st7571_set_position(struct st7571_device *st7571, int x, int y)
+{
+	u8 cmd_list[] = {
+		ST7571_SET_COLUMN_LSB(x),
+		ST7571_SET_COLUMN_MSB(x),
+		ST7571_SET_PAGE(y / ST7571_PAGE_HEIGHT),
+	};
+
+	return st7571_send_command_list(st7571, cmd_list, ARRAY_SIZE(cmd_list));
+}
+
+static int st7571_fb_clear_screen(struct st7571_device *st7571)
+{
+	u32 npixels = st7571->ncols * round_up(st7571->nlines, ST7571_PAGE_HEIGHT) * st7571->bpp;
+	char pixelvalue = 0x00;
+
+	st7571_set_position(st7571, 0, 0);
+	for (int i = 0; i < npixels; i++)
+		regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, &pixelvalue, 1);
+
+	return 0;
+}
+
+static void st7571_prepare_buffer_monochrome(struct st7571_device *st7571,
+					     const struct iosys_map *vmap,
+					     struct drm_framebuffer *fb,
+					     struct drm_rect *rect,
+					     struct drm_format_conv_state *fmtcnv_state)
+{
+	unsigned int dst_pitch;
+	struct iosys_map dst;
+	u32 size;
+
+	switch (fb->format->format) {
+	case DRM_FORMAT_XRGB8888:
+		dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 8);
+		iosys_map_set_vaddr(&dst, st7571->hwbuf);
+
+		drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, vmap, fb, rect, fmtcnv_state);
+		break;
+
+	case DRM_FORMAT_R1:
+		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
+		memcpy(st7571->hwbuf, vmap->vaddr, size);
+		break;
+	}
+}
+
+static void st7571_prepare_buffer_grayscale(struct st7571_device *st7571,
+					    const struct iosys_map *vmap,
+					    struct drm_framebuffer *fb,
+					    struct drm_rect *rect,
+					    struct drm_format_conv_state *fmtcnv_state)
+{
+	u32 size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
+	unsigned int dst_pitch;
+	struct iosys_map dst;
+
+	switch (fb->format->format) {
+	case DRM_FORMAT_XRGB8888:
+		dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 4);
+		iosys_map_set_vaddr(&dst, st7571->hwbuf);
+
+		drm_fb_xrgb8888_to_gray2(&dst, &dst_pitch, vmap, fb, rect, fmtcnv_state);
+		break;
+
+	case DRM_FORMAT_R1:
+		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 8;
+		memcpy(st7571->hwbuf, vmap->vaddr, size);
+		break;
+
+	case DRM_FORMAT_R2:
+		size = (rect->x2 - rect->x1) * (rect->y2 - rect->y1) / 4;
+		memcpy(st7571->hwbuf, vmap->vaddr, size);
+		break;
+	}
+}
+
+static int st7571_fb_update_rect_monochrome(struct drm_framebuffer *fb, struct drm_rect *rect)
+{
+	struct st7571_device *st7571 = drm_to_st7571(fb->dev);
+	char *row = st7571->row;
+
+	/* Align y to display page boundaries */
+	rect->y1 = round_down(rect->y1, ST7571_PAGE_HEIGHT);
+	rect->y2 = min_t(unsigned int, round_up(rect->y2, ST7571_PAGE_HEIGHT), st7571->nlines);
+
+	for (int y = rect->y1; y < rect->y2; y += ST7571_PAGE_HEIGHT) {
+		for (int x = rect->x1; x < rect->x2; x++)
+			row[x] = st7571_transform_xy(st7571->hwbuf, x, y, 1);
+
+		st7571_set_position(st7571, rect->x1, y);
+
+		/* TODO: Investige why we can't write multiple bytes at once */
+		for (int x = rect->x1; x < rect->x2; x++)
+			regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
+	}
+
+	return 0;
+}
+
+static int st7571_fb_update_rect_grayscale(struct drm_framebuffer *fb, struct drm_rect *rect)
+{
+	struct st7571_device *st7571 = drm_to_st7571(fb->dev);
+	u32 format = fb->format->format;
+	char *row = st7571->row;
+	int x1;
+	int x2;
+
+	/* Align y to display page boundaries */
+	rect->y1 = round_down(rect->y1, ST7571_PAGE_HEIGHT);
+	rect->y2 = min_t(unsigned int, round_up(rect->y2, ST7571_PAGE_HEIGHT), st7571->nlines);
+
+	switch (format) {
+	case DRM_FORMAT_R1:
+		x1 = rect->x1 * 1;
+		x2 = rect->x2 * 1;
+		break;
+	case DRM_FORMAT_R2:
+		fallthrough;
+	case DRM_FORMAT_XRGB8888:
+		x1 = rect->x1 * 2;
+		x2 = rect->x2 * 2;
+		break;
+	}
+
+	for (int y = rect->y1; y < rect->y2; y += ST7571_PAGE_HEIGHT) {
+		for (int x = x1; x < x2; x++)
+			row[x] = st7571_transform_xy(st7571->hwbuf, x, y, 2);
+
+		st7571_set_position(st7571, rect->x1, y);
+
+		/* TODO: Investige why we can't write multiple bytes at once */
+		for (int x = x1; x < x2; x++) {
+			regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
+
+			/*
+			 * As the display supports grayscale, all pixels must be written as two bits
+			 * even if the format is monochrome.
+			 *
+			 * The bit values maps to the following grayscale:
+			 * 0 0 = Black
+			 * 0 1 = Dark gray
+			 * 1 0 = Light gray
+			 * 1 1 = White
+			 *
+			 * For monochrome formats, write the same value twice to get
+			 * either a black or white pixel.
+			 */
+			if (format == DRM_FORMAT_R1)
+				regmap_bulk_write(st7571->regmap, ST7571_DATA_MODE, row + x, 1);
+		}
+	}
+
+	return 0;
+}
+
+static int st7571_connector_get_modes(struct drm_connector *conn)
+{
+	struct st7571_device *st7571 = drm_to_st7571(conn->dev);
+
+	return drm_connector_helper_get_modes_fixed(conn, &st7571->mode);
+}
+
+static const struct drm_connector_helper_funcs st7571_connector_helper_funcs = {
+	.get_modes = st7571_connector_get_modes,
+};
+
+static const struct st7571_panel_format st7571_monochrome = {
+	.prepare_buffer = st7571_prepare_buffer_monochrome,
+	.update_rect = st7571_fb_update_rect_monochrome,
+	.mode = ST7571_COLOR_MODE_BLACKWHITE,
+	.formats = {
+		DRM_FORMAT_XRGB8888,
+		DRM_FORMAT_R1,
+	},
+	.nformats = 2,
+};
+
+static const struct st7571_panel_format st7571_grayscale = {
+	.prepare_buffer = st7571_prepare_buffer_grayscale,
+	.update_rect = st7571_fb_update_rect_grayscale,
+	.mode = ST7571_COLOR_MODE_GRAY,
+	.formats = {
+		DRM_FORMAT_XRGB8888,
+		DRM_FORMAT_R1,
+		DRM_FORMAT_R2,
+	},
+	.nformats = 3,
+};
+
+static const u64 st7571_primary_plane_fmtmods[] = {
+	DRM_FORMAT_MOD_LINEAR,
+	DRM_FORMAT_MOD_INVALID
+};
+
+static int st7571_primary_plane_helper_atomic_check(struct drm_plane *plane,
+						    struct drm_atomic_state *state)
+{
+	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_crtc *new_crtc = new_plane_state->crtc;
+	struct drm_crtc_state *new_crtc_state = NULL;
+
+	if (new_crtc)
+		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
+
+	return drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
+						   DRM_PLANE_NO_SCALING,
+						   DRM_PLANE_NO_SCALING,
+						   false, false);
+}
+
+static void st7571_primary_plane_helper_atomic_update(struct drm_plane *plane,
+						      struct drm_atomic_state *state)
+{
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
+	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+	struct drm_framebuffer *fb = plane_state->fb;
+	struct drm_atomic_helper_damage_iter iter;
+	struct drm_device *drm = plane->dev;
+	struct drm_rect damage;
+	struct st7571_device *st7571 = drm_to_st7571(plane->dev);
+	int ret, idx;
+
+	if (!fb)
+		return; /* no framebuffer; plane is disabled */
+
+	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
+	if (ret)
+		return;
+
+	if (!drm_dev_enter(drm, &idx))
+		goto out_drm_gem_fb_end_cpu_access;
+
+	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+	drm_atomic_for_each_plane_damage(&iter, &damage) {
+		st7571->pformat->prepare_buffer(st7571,
+						&shadow_plane_state->data[0],
+						fb, &damage,
+						&shadow_plane_state->fmtcnv_state);
+
+		st7571->pformat->update_rect(fb, &damage);
+	}
+
+	drm_dev_exit(idx);
+
+out_drm_gem_fb_end_cpu_access:
+	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
+}
+
+static void st7571_primary_plane_helper_atomic_disable(struct drm_plane *plane,
+						       struct drm_atomic_state *state)
+{
+	struct drm_device *drm = plane->dev;
+	struct st7571_device *st7571 = drm_to_st7571(plane->dev);
+	int idx;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	st7571_fb_clear_screen(st7571);
+	drm_dev_exit(idx);
+}
+
+static const struct drm_plane_helper_funcs st7571_primary_plane_helper_funcs = {
+	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+	.atomic_check = st7571_primary_plane_helper_atomic_check,
+	.atomic_update = st7571_primary_plane_helper_atomic_update,
+	.atomic_disable = st7571_primary_plane_helper_atomic_disable,
+};
+
+static const struct drm_plane_funcs st7571_primary_plane_funcs = {
+	.update_plane = drm_atomic_helper_update_plane,
+	.disable_plane = drm_atomic_helper_disable_plane,
+	.destroy = drm_plane_cleanup,
+	DRM_GEM_SHADOW_PLANE_FUNCS,
+};
+
+/*
+ * CRTC
+ */
+
+static enum drm_mode_status st7571_crtc_mode_valid(struct drm_crtc *crtc,
+						   const struct drm_display_mode *mode)
+{
+	struct st7571_device *st7571 = drm_to_st7571(crtc->dev);
+
+	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &st7571->mode);
+}
+
+static const struct drm_crtc_helper_funcs st7571_crtc_helper_funcs = {
+	.atomic_check = drm_crtc_helper_atomic_check,
+	.mode_valid = st7571_crtc_mode_valid,
+};
+
+static const struct drm_crtc_funcs st7571_crtc_funcs = {
+	.reset = drm_atomic_helper_crtc_reset,
+	.destroy = drm_crtc_cleanup,
+	.set_config = drm_atomic_helper_set_config,
+	.page_flip = drm_atomic_helper_page_flip,
+	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+};
+
+/*
+ * Encoder
+ */
+
+static void st7571_encoder_atomic_enable(struct drm_encoder *encoder,
+					 struct drm_atomic_state *state)
+{
+	struct drm_device *drm = encoder->dev;
+	struct st7571_device *st7571 = drm_to_st7571(drm);
+	u8 command = ST7571_DISPLAY_ON;
+	int ret;
+
+	ret = st7571->pdata->init(st7571);
+	if (ret)
+		return;
+
+	st7571_send_command_list(st7571, &command, 1);
+}
+
+static void st7571_encoder_atomic_disable(struct drm_encoder *encoder,
+					  struct drm_atomic_state *state)
+{
+	struct drm_device *drm = encoder->dev;
+	struct st7571_device *st7571 = drm_to_st7571(drm);
+	u8 command = ST7571_DISPLAY_OFF;
+
+	st7571_send_command_list(st7571, &command, 1);
+}
+
+static const struct drm_encoder_funcs st7571_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+
+};
+
+static const struct drm_encoder_helper_funcs st7571_encoder_helper_funcs = {
+	.atomic_enable = st7571_encoder_atomic_enable,
+	.atomic_disable = st7571_encoder_atomic_disable,
+};
+
+/*
+ * Connector
+ */
+
+static const struct drm_connector_funcs st7571_connector_funcs = {
+	.reset = drm_atomic_helper_connector_reset,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = drm_connector_cleanup,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static const struct drm_mode_config_funcs st7571_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create_with_dirty,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static struct drm_display_mode st7571_mode(struct st7571_device *st7571)
+{
+	struct drm_display_mode mode = {
+		DRM_SIMPLE_MODE(st7571->ncols, st7571->nlines,
+				st7571->width_mm, st7571->height_mm),
+	};
+
+	return mode;
+}
+
+static int st7571_mode_config_init(struct st7571_device *st7571)
+{
+	struct drm_device *drm = &st7571->drm;
+	const struct st7571_panel_constraints *constraints = &st7571->pdata->constraints;
+	int ret;
+
+	ret = drmm_mode_config_init(drm);
+	if (ret)
+		return ret;
+
+	drm->mode_config.min_width = constraints->min_ncols;
+	drm->mode_config.min_height = constraints->min_nlines;
+	drm->mode_config.max_width = constraints->max_ncols;
+	drm->mode_config.max_height = constraints->max_nlines;
+	drm->mode_config.preferred_depth = 24;
+	drm->mode_config.funcs = &st7571_mode_config_funcs;
+
+	return 0;
+}
+
+static int st7571_plane_init(struct st7571_device *st7571,
+			     const struct st7571_panel_format *pformat)
+{
+	struct drm_plane *primary_plane = &st7571->primary_plane;
+	struct drm_device *drm = &st7571->drm;
+	int ret;
+
+	ret = drm_universal_plane_init(drm, primary_plane, 0,
+				       &st7571_primary_plane_funcs,
+				       pformat->formats,
+				       pformat->nformats,
+				       st7571_primary_plane_fmtmods,
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret)
+		return ret;
+
+	drm_plane_helper_add(primary_plane, &st7571_primary_plane_helper_funcs);
+	drm_plane_enable_fb_damage_clips(primary_plane);
+
+	return 0;
+}
+
+static int st7571_crtc_init(struct st7571_device *st7571)
+{
+	struct drm_plane *primary_plane = &st7571->primary_plane;
+	struct drm_crtc *crtc = &st7571->crtc;
+	struct drm_device *drm = &st7571->drm;
+	int ret;
+
+	ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
+					&st7571_crtc_funcs, NULL);
+	if (ret)
+		return ret;
+
+	drm_crtc_helper_add(crtc, &st7571_crtc_helper_funcs);
+
+	return 0;
+}
+
+static int st7571_encoder_init(struct st7571_device *st7571)
+{
+	struct drm_encoder *encoder = &st7571->encoder;
+	struct drm_crtc *crtc = &st7571->crtc;
+	struct drm_device *drm = &st7571->drm;
+	int ret;
+
+	ret = drm_encoder_init(drm, encoder, &st7571_encoder_funcs, DRM_MODE_ENCODER_NONE, NULL);
+	if (ret)
+		return ret;
+
+	drm_encoder_helper_add(encoder, &st7571_encoder_helper_funcs);
+
+	encoder->possible_crtcs = drm_crtc_mask(crtc);
+
+	return 0;
+}
+
+static int st7571_connector_init(struct st7571_device *st7571)
+{
+	struct drm_connector *connector = &st7571->connector;
+	struct drm_encoder *encoder = &st7571->encoder;
+	struct drm_device *drm = &st7571->drm;
+	int ret;
+
+	ret = drm_connector_init(drm, connector, &st7571_connector_funcs,
+				 DRM_MODE_CONNECTOR_Unknown);
+	if (ret)
+		return ret;
+
+	drm_connector_helper_add(connector, &st7571_connector_helper_funcs);
+
+	return drm_connector_attach_encoder(connector, encoder);
+}
+
+DEFINE_DRM_GEM_FOPS(st7571_fops);
+
+static const struct drm_driver st7571_driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
+
+	.name		 = DRIVER_NAME,
+	.desc		 = DRIVER_DESC,
+	.major		 = DRIVER_MAJOR,
+	.minor		 = DRIVER_MINOR,
+
+	.fops		 = &st7571_fops,
+	DRM_GEM_SHMEM_DRIVER_OPS,
+	DRM_FBDEV_SHMEM_DRIVER_OPS,
+};
+
+static int st7571_validate_parameters(struct st7571_device *st7571)
+{
+	struct device *dev = st7571->dev;
+	const struct st7571_panel_constraints *constraints = &st7571->pdata->constraints;
+
+	if (st7571->width_mm  == 0) {
+		dev_err(dev, "Invalid panel width\n");
+		return -EINVAL;
+	}
+
+	if (st7571->height_mm == 0) {
+		dev_err(dev, "Invalid panel height\n");
+		return -EINVAL;
+	}
+
+	if (st7571->nlines < constraints->min_nlines ||
+	    st7571->nlines > constraints->max_nlines) {
+		dev_err(dev, "Invalid timing configuration.\n");
+		return -EINVAL;
+	}
+
+	if (st7571->startline + st7571->nlines > constraints->max_nlines) {
+		dev_err(dev, "Invalid timing configuration.\n");
+		return -EINVAL;
+	}
+
+	if (st7571->ncols < constraints->min_ncols ||
+	    st7571->ncols > constraints->max_ncols) {
+		dev_err(dev, "Invalid timing configuration.\n");
+		return -EINVAL;
+	}
+
+	if (st7571->grayscale && !constraints->support_grayscale) {
+		dev_err(dev, "Grayscale not supported\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int st7567_parse_dt(struct st7571_device *st7567)
+{
+	struct device *dev = st7567->dev;
+	struct device_node *np = dev->of_node;
+	struct display_timing dt;
+	int ret;
+
+	ret = of_get_display_timing(np, "panel-timing", &dt);
+	if (ret) {
+		dev_err(dev, "Failed to get display timing from DT\n");
+		return ret;
+	}
+
+	of_property_read_u32(np, "width-mm", &st7567->width_mm);
+	of_property_read_u32(np, "height-mm", &st7567->height_mm);
+	st7567->inverted = of_property_read_bool(np, "sitronix,inverted");
+
+	st7567->pformat = &st7571_monochrome;
+	st7567->bpp = 1;
+
+	st7567->startline = dt.vfront_porch.typ;
+	st7567->nlines = dt.vactive.typ;
+	st7567->ncols = dt.hactive.typ;
+
+	return 0;
+}
+
+static int st7571_parse_dt(struct st7571_device *st7571)
+{
+	struct device *dev = st7571->dev;
+	struct device_node *np = dev->of_node;
+	struct display_timing dt;
+	int ret;
+
+	ret = of_get_display_timing(np, "panel-timing", &dt);
+	if (ret) {
+		dev_err(dev, "Failed to get display timing from DT\n");
+		return ret;
+	}
+
+	of_property_read_u32(np, "width-mm", &st7571->width_mm);
+	of_property_read_u32(np, "height-mm", &st7571->height_mm);
+	st7571->grayscale = of_property_read_bool(np, "sitronix,grayscale");
+	st7571->inverted = of_property_read_bool(np, "sitronix,inverted");
+
+	if (st7571->grayscale) {
+		st7571->pformat = &st7571_grayscale;
+		st7571->bpp = 2;
+	} else {
+		st7571->pformat = &st7571_monochrome;
+		st7571->bpp = 1;
+	}
+
+	st7571->startline = dt.vfront_porch.typ;
+	st7571->nlines = dt.vactive.typ;
+	st7571->ncols = dt.hactive.typ;
+
+	st7571->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(st7571->reset))
+		return dev_err_probe(dev, PTR_ERR(st7571->reset),
+				     "Failed to get reset gpio\n");
+
+	return 0;
+}
+
+static void st7571_reset(struct st7571_device *st7571)
+{
+	gpiod_set_value_cansleep(st7571->reset, 1);
+	fsleep(20);
+	gpiod_set_value_cansleep(st7571->reset, 0);
+}
+
+static int st7567_lcd_init(struct st7571_device *st7567)
+{
+	/*
+	 * Most of the initialization sequence is taken directly from the
+	 * referential initial code in the ST7567 datasheet.
+	 */
+	u8 commands[] = {
+		ST7571_DISPLAY_OFF,
+
+		ST7567_SET_LCD_BIAS(1),
+
+		ST7571_SET_SEG_SCAN_DIR(0),
+		ST7571_SET_COM_SCAN_DIR(1),
+
+		ST7571_SET_REGULATOR_REG(4),
+		ST7571_SET_CONTRAST_MSB,
+		ST7571_SET_CONTRAST_LSB(0x20),
+
+		ST7571_SET_START_LINE_MSB,
+		ST7571_SET_START_LINE_LSB(st7567->startline),
+
+		ST7571_SET_POWER(0x4),	/* Power Control, VC: ON, VR: OFF, VF: OFF */
+		ST7571_SET_POWER(0x6),	/* Power Control, VC: ON, VR: ON, VF: OFF */
+		ST7571_SET_POWER(0x7),	/* Power Control, VC: ON, VR: ON, VF: ON */
+
+		ST7571_SET_REVERSE(st7567->inverted ? 1 : 0),
+		ST7571_SET_ENTIRE_DISPLAY_ON(0),
+	};
+
+	return st7571_send_command_list(st7567, commands, ARRAY_SIZE(commands));
+}
+
+static int st7571_lcd_init(struct st7571_device *st7571)
+{
+	/*
+	 * Most of the initialization sequence is taken directly from the
+	 * referential initial code in the ST7571 datasheet.
+	 */
+	u8 commands[] = {
+		ST7571_DISPLAY_OFF,
+
+		ST7571_SET_MODE_MSB,
+		ST7571_SET_MODE_LSB(0x2e),
+
+		ST7571_SET_SEG_SCAN_DIR(0),
+		ST7571_SET_COM_SCAN_DIR(1),
+
+		ST7571_SET_COM0_MSB,
+		ST7571_SET_COM0_LSB(0x00),
+
+		ST7571_SET_START_LINE_MSB,
+		ST7571_SET_START_LINE_LSB(st7571->startline),
+
+		ST7571_OSC_ON,
+		ST7571_SET_REGULATOR_REG(5),
+		ST7571_SET_CONTRAST_MSB,
+		ST7571_SET_CONTRAST_LSB(0x33),
+		ST7571_SET_LCD_BIAS(0x04),
+		ST7571_SET_DISPLAY_DUTY_MSB,
+		ST7571_SET_DISPLAY_DUTY_LSB(st7571->nlines),
+
+		ST7571_SET_POWER(0x4),	/* Power Control, VC: ON, VR: OFF, VF: OFF */
+		ST7571_SET_POWER(0x6),	/* Power Control, VC: ON, VR: ON, VF: OFF */
+		ST7571_SET_POWER(0x7),	/* Power Control, VC: ON, VR: ON, VF: ON */
+
+		ST7571_COMMAND_SET_3,
+		ST7571_SET_COLOR_MODE(st7571->pformat->mode),
+		ST7571_COMMAND_SET_NORMAL,
+
+		ST7571_SET_REVERSE(st7571->inverted ? 1 : 0),
+		ST7571_SET_ENTIRE_DISPLAY_ON(0),
+	};
+
+	/* Perform a reset before initializing the controller */
+	st7571_reset(st7571);
+
+	return st7571_send_command_list(st7571, commands, ARRAY_SIZE(commands));
+}
+
+struct st7571_device *st7571_probe(struct device *dev,
+				   struct regmap *regmap)
+{
+	struct st7571_device *st7571;
+	struct drm_device *drm;
+	int ret;
+
+	st7571 = devm_drm_dev_alloc(dev, &st7571_driver,
+				    struct st7571_device, drm);
+	if (IS_ERR(st7571))
+		return st7571;
+
+	drm = &st7571->drm;
+	st7571->dev = dev;
+	st7571->pdata = device_get_match_data(st7571->dev);
+
+	ret = st7571->pdata->parse_dt(st7571);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = st7571_validate_parameters(st7571);
+	if (ret)
+		return ERR_PTR(ret);
+
+	st7571->mode = st7571_mode(st7571);
+	st7571->regmap = regmap;
+
+	st7571->hwbuf = devm_kzalloc(st7571->dev,
+				     (st7571->nlines * st7571->ncols * st7571->bpp) / 8,
+				     GFP_KERNEL);
+	if (!st7571->hwbuf)
+		return ERR_PTR(-ENOMEM);
+
+	st7571->row = devm_kzalloc(st7571->dev,
+				   (st7571->ncols * st7571->bpp),
+				   GFP_KERNEL);
+	if (!st7571->row)
+		return ERR_PTR(-ENOMEM);
+
+	ret = st7571_mode_config_init(st7571);
+	if (ret) {
+		dev_err(st7571->dev, "Failed to initialize mode config\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = st7571_plane_init(st7571, st7571->pformat);
+	if (ret) {
+		dev_err(st7571->dev, "Failed to initialize primary plane\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = st7571_crtc_init(st7571);
+	if (ret < 0) {
+		dev_err(st7571->dev, "Failed to initialize CRTC\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = st7571_encoder_init(st7571);
+	if (ret < 0) {
+		dev_err(st7571->dev, "Failed to initialize encoder\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = st7571_connector_init(st7571);
+	if (ret < 0) {
+		dev_err(st7571->dev, "Failed to initialize connector\n");
+		return ERR_PTR(ret);
+	}
+
+	drm_mode_config_reset(drm);
+
+	ret = drm_dev_register(drm, 0);
+	if (ret) {
+		dev_err(st7571->dev, "Failed to register DRM device\n");
+		return ERR_PTR(ret);
+	}
+
+	drm_client_setup(drm, NULL);
+	return st7571;
+}
+EXPORT_SYMBOL_GPL(st7571_probe);
+
+void st7571_remove(struct st7571_device *st7571)
+{
+	drm_dev_unplug(&st7571->drm);
+}
+EXPORT_SYMBOL_GPL(st7571_remove);
+
+const struct st7571_panel_data st7567_config = {
+	.init = st7567_lcd_init,
+	.parse_dt = st7567_parse_dt,
+	.constraints = {
+		.min_nlines = 1,
+		.max_nlines = 64,
+		.min_ncols = 128,
+		.max_ncols = 128,
+		.support_grayscale = false,
+	},
+};
+EXPORT_SYMBOL_NS_GPL(st7567_config, "DRM_ST7571");
+
+const struct st7571_panel_data st7571_config = {
+	.init = st7571_lcd_init,
+	.parse_dt = st7571_parse_dt,
+	.constraints = {
+		.min_nlines = 1,
+		.max_nlines = 128,
+		.min_ncols = 128,
+		.max_ncols = 128,
+		.support_grayscale = true,
+	},
+};
+EXPORT_SYMBOL_NS_GPL(st7571_config, "DRM_ST7571");
+
+MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
+MODULE_DESCRIPTION("DRM Driver for Sitronix ST7571 LCD controller");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/sitronix/st7571.h b/drivers/gpu/drm/sitronix/st7571.h
index f62c57ddb99ebe82f63048cc2ccf75a81518d717..af264f2e2ea47e7813067733e7051db9529ca1f1 100644
--- a/drivers/gpu/drm/sitronix/st7571.h
+++ b/drivers/gpu/drm/sitronix/st7571.h
@@ -82,4 +82,10 @@ struct st7571_device {
 	u8 *row;
 };
 
+extern const struct st7571_panel_data st7567_config;
+extern const struct st7571_panel_data st7571_config;
+
+struct st7571_device *st7571_probe(struct device *dev, struct regmap *regmap);
+void st7571_remove(struct st7571_device *st7571);
+
 #endif /* __ST7571_H__ */

-- 
2.50.1