workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

9 files changed, 3072 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sitronix/Kconfig b/drivers/gpu/drm/sitronix/Kconfig
new file mode 100644
index 000000000..41a428ef8
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/Kconfig
@@ -0,0 +1,80 @@
+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 VIDEOMODE_HELPERS
+	help
+	  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
+	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.
+
+config DRM_ST7571_SPI
+	tristate "DRM support for Sitronix ST7567/ST7571 display panels (SPI)"
+	depends on DRM_ST7571 && SPI
+	select REGMAP_SPI
+	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 SPI bus.
+
+	  if M is selected the module will be called st7571-spi.
+
+config DRM_ST7586
+	tristate "DRM support for Sitronix ST7586 display panels"
+	depends on DRM && SPI
+	select DRM_CLIENT_SELECTION
+	select DRM_KMS_HELPER
+	select DRM_GEM_DMA_HELPER
+	select DRM_MIPI_DBI
+	help
+	  DRM driver for the following Sitronix ST7586 panels:
+	  * LEGO MINDSTORMS EV3
+
+	  If M is selected the module will be called st7586.
+
+config DRM_ST7735R
+	tristate "DRM support for Sitronix ST7715R/ST7735R display panels"
+	depends on DRM && SPI
+	select DRM_CLIENT_SELECTION
+	select DRM_KMS_HELPER
+	select DRM_GEM_DMA_HELPER
+	select DRM_MIPI_DBI
+	select BACKLIGHT_CLASS_DEVICE
+	help
+	  DRM driver for Sitronix ST7715R/ST7735R with one of the following
+	  LCDs:
+	  * Jianda JD-T18003-T01 1.8" 128x160 TFT
+	  * Okaya RH128128T 1.44" 128x128 TFT
+
+	  If M is selected the module will be called st7735r.
+
+config DRM_ST7920
+	tristate "DRM support for Sitronix ST7920 LCD displays"
+	depends on DRM && SPI && MMU
+	select DRM_GEM_SHMEM_HELPER
+	select DRM_KMS_HELPER
+	select REGMAP_SPI
+	help
+	  DRM driver for the ST7920 Sitronix LCD controllers.
+
+	  If M is selected the module will be called st7920.
diff --git a/drivers/gpu/drm/sitronix/Makefile b/drivers/gpu/drm/sitronix/Makefile
new file mode 100644
index 000000000..d03beff37
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/Makefile
@@ -0,0 +1,6 @@
+obj-$(CONFIG_DRM_ST7571)		+= st7571.o
+obj-$(CONFIG_DRM_ST7571_I2C)		+= st7571-i2c.o
+obj-$(CONFIG_DRM_ST7571_SPI)		+= st7571-spi.o
+obj-$(CONFIG_DRM_ST7586)		+= st7586.o
+obj-$(CONFIG_DRM_ST7735R)		+= st7735r.o
+obj-$(CONFIG_DRM_ST7920)		+= st7920.o
diff --git a/drivers/gpu/drm/sitronix/st7571-i2c.c b/drivers/gpu/drm/sitronix/st7571-i2c.c
new file mode 100644
index 000000000..44bc94be3
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7571-i2c.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Sitronix ST7571 connected via I2C bus.
+ *
+ * Copyright (C) 2025 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "st7571.h"
+
+struct st7571_i2c_transport {
+	struct i2c_client *client;
+
+	/*
+	 * Depending on the hardware design, the acknowledge signal may be hard to
+	 * recognize as a valid logic "0" level.
+	 * Therefor, ignore NAK if possible to stay compatible with most hardware designs
+	 * and off-the-shelf panels out there.
+	 *
+	 * From section 6.4 MICROPOCESSOR INTERFACE section in the datasheet:
+	 *
+	 * "By connecting SDA_OUT to SDA_IN externally, the SDA line becomes fully
+	 * I2C interface compatible.
+	 * Separating acknowledge-output from serial data
+	 * input is advantageous for chip-on-glass (COG) applications. In COG
+	 * applications, the ITO resistance and the pull-up resistor will form a
+	 * voltage  divider, which affects acknowledge-signal level. Larger ITO
+	 * resistance will raise the acknowledged-signal level and system cannot
+	 * recognize this level as a valid logic “0” level. By separating SDA_IN from
+	 * SDA_OUT, the IC can be used in a mode that ignores the acknowledge-bit.
+	 * For applications which check acknowledge-bit, it is necessary to minimize
+	 * the ITO resistance of the SDA_OUT trace to guarantee a valid low level."
+	 *
+	 */
+	bool ignore_nak;
+};
+
+static int st7571_i2c_regmap_write(void *context, const void *data, size_t count)
+{
+	struct st7571_i2c_transport *t = context;
+	int ret;
+
+	struct i2c_msg msg = {
+		.addr = t->client->addr,
+		.flags = t->ignore_nak ? I2C_M_IGNORE_NAK : 0,
+		.len = count,
+		.buf = (u8 *)data
+	};
+
+	ret = i2c_transfer(t->client->adapter, &msg, 1);
+
+	/*
+	 * Unfortunately, there is no way to check if the transfer failed because of
+	 * a NAK or something else as I2C bus drivers use different return values for NAK.
+	 *
+	 * However, if the transfer fails and ignore_nak is set, we know it is an error.
+	 */
+	if (ret < 0 && t->ignore_nak)
+		return ret;
+
+	return 0;
+}
+
+/* The st7571 driver does not read registers but regmap expects a .read */
+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 const struct regmap_bus st7571_i2c_regmap_bus = {
+	.read = st7571_i2c_regmap_read,
+	.write = st7571_i2c_regmap_write,
+};
+
+static const struct regmap_config st7571_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.use_single_write = true,
+};
+
+static int st7571_i2c_probe(struct i2c_client *client)
+{
+	struct st7571_device *st7571;
+	struct st7571_i2c_transport *t;
+	struct regmap *regmap;
+
+	t = devm_kzalloc(&client->dev, sizeof(*t), GFP_KERNEL);
+	if (!t)
+		return -ENOMEM;
+
+	t->client = client;
+
+	/*
+	 * The hardware design could make it hard to detect a NAK on the I2C bus.
+	 * If the adapter does not support protocol mangling do
+	 * not set the I2C_M_IGNORE_NAK flag at the expense * of possible
+	 * cruft in the logs.
+	 */
+	if (i2c_check_functionality(client->adapter, I2C_FUNC_PROTOCOL_MANGLING))
+		t->ignore_nak = true;
+
+	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");
+	}
+
+	st7571 = st7571_probe(&client->dev, regmap);
+	if (IS_ERR(st7571))
+		return dev_err_probe(&client->dev, PTR_ERR(st7571),
+				     "Failed to initialize regmap\n");
+
+	i2c_set_clientdata(client, st7571);
+	return 0;
+}
+
+static void st7571_i2c_remove(struct i2c_client *client)
+{
+	struct st7571_device *st7571 = i2c_get_clientdata(client);
+
+	st7571_remove(st7571);
+}
+
+static const struct of_device_id st7571_of_match[] = {
+	{ .compatible = "sitronix,st7567", .data = &st7567_config },
+	{ .compatible = "sitronix,st7571", .data = &st7571_config },
+	{},
+};
+MODULE_DEVICE_TABLE(of, st7571_of_match);
+
+static const struct i2c_device_id st7571_id[] = {
+	{ "st7567", 0 },
+	{ "st7571", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, st7571_id);
+
+static struct i2c_driver st7571_i2c_driver = {
+	.driver = {
+		.name = "st7571-i2c",
+		.of_match_table = st7571_of_match,
+	},
+	.probe = st7571_i2c_probe,
+	.remove = st7571_i2c_remove,
+	.id_table = st7571_id,
+};
+
+module_i2c_driver(st7571_i2c_driver);
+
+MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
+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-spi.c b/drivers/gpu/drm/sitronix/st7571-spi.c
new file mode 100644
index 000000000..0206e9162
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7571-spi.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Sitronix ST7571 connected via SPI bus.
+ *
+ * Copyright (C) 2025 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "st7571.h"
+
+static const struct regmap_config st7571_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.can_multi_write = true,
+};
+
+static int st7571_spi_probe(struct spi_device *spi)
+{
+	struct st7571_device *st7571;
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_spi(spi, &st7571_spi_regmap_config);
+	if (IS_ERR(regmap)) {
+		return dev_err_probe(&spi->dev, PTR_ERR(regmap),
+				     "Failed to initialize regmap\n");
+	}
+
+	st7571 = st7571_probe(&spi->dev, regmap);
+	if (IS_ERR(st7571))
+		return dev_err_probe(&spi->dev, PTR_ERR(st7571),
+				     "Failed to initialize regmap\n");
+
+	spi_set_drvdata(spi, st7571);
+	return 0;
+}
+
+static void st7571_spi_remove(struct spi_device *spi)
+{
+	struct st7571_device *st7571 = spi_get_drvdata(spi);
+
+	st7571_remove(st7571);
+}
+
+static const struct of_device_id st7571_of_match[] = {
+	{ .compatible = "sitronix,st7567", .data = &st7567_config },
+	{ .compatible = "sitronix,st7571", .data = &st7571_config },
+	{},
+};
+MODULE_DEVICE_TABLE(of, st7571_of_match);
+
+static const struct spi_device_id st7571_spi_id[] = {
+	{ "st7567", 0 },
+	{ "st7571", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, st7571_spi_id);
+
+static struct spi_driver st7571_spi_driver = {
+	.driver = {
+		.name = "st7571-spi",
+		.of_match_table = st7571_of_match,
+	},
+	.probe = st7571_spi_probe,
+	.remove = st7571_spi_remove,
+	.id_table = st7571_spi_id,
+};
+
+module_spi_driver(st7571_spi_driver);
+
+MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
+MODULE_DESCRIPTION("DRM Driver for Sitronix ST7571 LCD controller (SPI)");
+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 000000000..20954c33e
--- /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_commit *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_commit *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_commit *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_commit *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_commit *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
new file mode 100644
index 000000000..af264f2e2
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7571.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Header file for:
+ * Driver for Sitronix ST7571, a 4 level gray scale dot matrix LCD controller
+ *
+ * Copyright (C) 2025 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+
+#ifndef __ST7571_H__
+#define __ST7571_H__
+
+#include <drm/drm_connector.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_format_helper.h>
+
+#include <linux/regmap.h>
+
+enum st7571_color_mode {
+	ST7571_COLOR_MODE_GRAY = 0,
+	ST7571_COLOR_MODE_BLACKWHITE = 1,
+};
+
+struct st7571_device;
+
+struct st7571_panel_constraints {
+	u32 min_nlines;
+	u32 max_nlines;
+	u32 min_ncols;
+	u32 max_ncols;
+	bool support_grayscale;
+};
+
+struct st7571_panel_data {
+	int (*init)(struct st7571_device *st7571);
+	int (*parse_dt)(struct st7571_device *st7571);
+	struct st7571_panel_constraints constraints;
+};
+
+struct st7571_panel_format {
+	void (*prepare_buffer)(struct st7571_device *st7571,
+			       const struct iosys_map *vmap,
+			       struct drm_framebuffer *fb,
+			       struct drm_rect *rect,
+			       struct drm_format_conv_state *fmtcnv_state);
+	int (*update_rect)(struct drm_framebuffer *fb, struct drm_rect *rect);
+	enum st7571_color_mode mode;
+	const u8 nformats;
+	const u32 formats[];
+};
+
+struct st7571_device {
+	struct drm_device drm;
+	struct device *dev;
+
+	struct drm_plane primary_plane;
+	struct drm_crtc crtc;
+	struct drm_encoder encoder;
+	struct drm_connector connector;
+
+	struct drm_display_mode mode;
+
+	const struct st7571_panel_format *pformat;
+	const struct st7571_panel_data *pdata;
+	struct gpio_desc *reset;
+	struct regmap *regmap;
+
+	bool grayscale;
+	bool inverted;
+	u32 height_mm;
+	u32 width_mm;
+	u32 startline;
+	u32 nlines;
+	u32 ncols;
+	u32 bpp;
+
+	/* Intermediate buffer in LCD friendly format */
+	u8 *hwbuf;
+
+	/* Row of (transformed) pixels ready to be written to the display */
+	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__ */
diff --git a/drivers/gpu/drm/sitronix/st7586.c b/drivers/gpu/drm/sitronix/st7586.c
new file mode 100644
index 000000000..28b2245f6
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7586.c
@@ -0,0 +1,498 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * DRM driver for Sitronix ST7586 panels
+ *
+ * Copyright 2017 David Lechner <david@lechnology.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+#include <drm/clients/drm_client_setup.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_dma_helper.h>
+#include <drm/drm_fbdev_dma.h>
+#include <drm/drm_format_helper.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_dma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_mipi_dbi.h>
+#include <drm/drm_print.h>
+#include <drm/drm_rect.h>
+
+/* controller-specific commands */
+#define ST7586_DISP_MODE_GRAY	0x38
+#define ST7586_DISP_MODE_MONO	0x39
+#define ST7586_ENABLE_DDRAM	0x3a
+#define ST7586_SET_DISP_DUTY	0xb0
+#define ST7586_SET_PART_DISP	0xb4
+#define ST7586_SET_NLINE_INV	0xb5
+#define ST7586_SET_VOP		0xc0
+#define ST7586_SET_BIAS_SYSTEM	0xc3
+#define ST7586_SET_BOOST_LEVEL	0xc4
+#define ST7586_SET_VOP_OFFSET	0xc7
+#define ST7586_ENABLE_ANALOG	0xd0
+#define ST7586_AUTO_READ_CTRL	0xd7
+#define ST7586_OTP_RW_CTRL	0xe0
+#define ST7586_OTP_CTRL_OUT	0xe1
+#define ST7586_OTP_READ		0xe3
+
+#define ST7586_DISP_CTRL_MX	BIT(6)
+#define ST7586_DISP_CTRL_MY	BIT(7)
+
+struct st7586_device {
+	struct mipi_dbi_dev dbidev;
+
+	struct drm_plane plane;
+	struct drm_crtc crtc;
+	struct drm_encoder encoder;
+	struct drm_connector connector;
+};
+
+static struct st7586_device *to_st7586_device(struct drm_device *dev)
+{
+	return container_of(drm_to_mipi_dbi_dev(dev), struct st7586_device, dbidev);
+}
+
+/*
+ * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
+ * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
+ * pixel using only 2 bits.
+ *
+ * |  D7  |  D6  |  D5  ||      |      || 2bpp |
+ * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
+ * +------+------+------++------+------++------+
+ * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
+ * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
+ * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
+ * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
+ */
+
+static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
+
+static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
+				       struct drm_framebuffer *fb,
+				       struct drm_rect *clip,
+				       struct drm_format_conv_state *fmtcnv_state)
+{
+	size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
+	unsigned int x, y;
+	u8 *src, *buf, val;
+	struct iosys_map dst_map, vmap;
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	iosys_map_set_vaddr(&dst_map, buf);
+	iosys_map_set_vaddr(&vmap, vaddr);
+	drm_fb_xrgb8888_to_gray8(&dst_map, NULL, &vmap, fb, clip, fmtcnv_state);
+	src = buf;
+
+	for (y = clip->y1; y < clip->y2; y++) {
+		for (x = clip->x1; x < clip->x2; x += 3) {
+			val = st7586_lookup[*src++ >> 6] << 5;
+			val |= st7586_lookup[*src++ >> 6] << 2;
+			val |= st7586_lookup[*src++ >> 6] >> 1;
+			*dst++ = val;
+		}
+	}
+
+	kfree(buf);
+}
+
+static int st7586_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
+			   struct drm_rect *clip, struct drm_format_conv_state *fmtcnv_state)
+{
+	int ret;
+
+	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
+	if (ret)
+		return ret;
+
+	st7586_xrgb8888_to_gray332(dst, src->vaddr, fb, clip, fmtcnv_state);
+
+	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
+
+	return 0;
+}
+
+static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
+			    struct drm_rect *rect, struct drm_format_conv_state *fmtcnv_state)
+{
+	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	int start, end, ret = 0;
+
+	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
+	rect->x1 = rounddown(rect->x1, 3);
+	rect->x2 = roundup(rect->x2, 3);
+
+	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
+
+	ret = st7586_buf_copy(dbidev->tx_buf, src, fb, rect, fmtcnv_state);
+	if (ret)
+		goto err_msg;
+
+	/* Pixels are packed 3 per byte */
+	start = rect->x1 / 3;
+	end = rect->x2 / 3;
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
+			 (start >> 8) & 0xFF, start & 0xFF,
+			 (end >> 8) & 0xFF, (end - 1) & 0xFF);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
+			 (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
+			 (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
+
+	ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
+				   (u8 *)dbidev->tx_buf,
+				   (end - start) * (rect->y2 - rect->y1));
+err_msg:
+	if (ret)
+		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
+}
+
+static const u32 st7586_plane_formats[] = {
+	DRM_FORMAT_XRGB8888,
+};
+
+static const u64 st7586_plane_format_modifiers[] = {
+	DRM_MIPI_DBI_PLANE_FORMAT_MODIFIERS,
+};
+
+static void st7586_plane_helper_atomic_update(struct drm_plane *plane,
+					      struct drm_atomic_commit *state)
+{
+	struct drm_plane_state *plane_state = plane->state;
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+	struct drm_framebuffer *fb = plane_state->fb;
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
+	struct drm_rect rect;
+	int idx;
+
+	if (!fb)
+		return;
+
+	if (!drm_dev_enter(plane->dev, &idx))
+		return;
+
+	if (drm_atomic_helper_damage_merged(old_plane_state, plane_state, &rect))
+		st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
+				&shadow_plane_state->fmtcnv_state);
+
+	drm_dev_exit(idx);
+}
+
+static const struct drm_plane_helper_funcs st7586_plane_helper_funcs = {
+	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+	.atomic_check = drm_mipi_dbi_plane_helper_atomic_check,
+	.atomic_update = st7586_plane_helper_atomic_update
+};
+
+static const struct drm_plane_funcs st7586_plane_funcs = {
+	DRM_MIPI_DBI_PLANE_FUNCS,
+	.destroy = drm_plane_cleanup,
+};
+
+static void st7586_crtc_helper_atomic_enable(struct drm_crtc *crtc,
+					     struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = crtc->dev;
+	struct st7586_device *st7586 = to_st7586_device(drm);
+	struct mipi_dbi_dev *dbidev = &st7586->dbidev;
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	int idx, ret;
+	u8 addr_mode;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	DRM_DEBUG_KMS("\n");
+
+	ret = mipi_dbi_poweron_reset(dbidev);
+	if (ret)
+		goto out_exit;
+
+	mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
+	mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
+
+	msleep(10);
+
+	mipi_dbi_command(dbi, ST7586_OTP_READ);
+
+	msleep(20);
+
+	mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
+
+	msleep(50);
+
+	mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
+	mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
+	mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
+	mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
+	mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
+	mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
+	mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
+	mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
+
+	switch (dbidev->rotation) {
+	default:
+		addr_mode = 0x00;
+		break;
+	case 90:
+		addr_mode = ST7586_DISP_CTRL_MY;
+		break;
+	case 180:
+		addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
+		break;
+	case 270:
+		addr_mode = ST7586_DISP_CTRL_MX;
+		break;
+	}
+	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+
+	mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
+	mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
+
+	msleep(100);
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+out_exit:
+	drm_dev_exit(idx);
+}
+
+static void st7586_crtc_helper_atomic_disable(struct drm_crtc *crtc,
+					      struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = crtc->dev;
+	struct st7586_device *st7586 = to_st7586_device(drm);
+	struct mipi_dbi_dev *dbidev = &st7586->dbidev;
+
+	/*
+	 * This callback is not protected by drm_dev_enter/exit since we want to
+	 * turn off the display on regular driver unload. It's highly unlikely
+	 * that the underlying SPI controller is gone should this be called after
+	 * unplug.
+	 */
+
+	DRM_DEBUG_KMS("\n");
+
+	mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
+}
+
+static const struct drm_crtc_helper_funcs st7586_crtc_helper_funcs = {
+	.mode_valid = drm_mipi_dbi_crtc_helper_mode_valid,
+	.atomic_check = drm_mipi_dbi_crtc_helper_atomic_check,
+	.atomic_enable = st7586_crtc_helper_atomic_enable,
+	.atomic_disable = st7586_crtc_helper_atomic_disable,
+};
+
+static const struct drm_crtc_funcs st7586_crtc_funcs = {
+	DRM_MIPI_DBI_CRTC_FUNCS,
+	.destroy = drm_crtc_cleanup,
+};
+
+static const struct drm_encoder_funcs st7586_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static const struct drm_connector_helper_funcs st7586_connector_helper_funcs = {
+	DRM_MIPI_DBI_CONNECTOR_HELPER_FUNCS,
+};
+
+static const struct drm_connector_funcs st7586_connector_funcs = {
+	DRM_MIPI_DBI_CONNECTOR_FUNCS,
+	.destroy = drm_connector_cleanup,
+};
+
+static const struct drm_mode_config_helper_funcs st7586_mode_config_helper_funcs = {
+	DRM_MIPI_DBI_MODE_CONFIG_HELPER_FUNCS,
+};
+
+static const struct drm_mode_config_funcs st7586_mode_config_funcs = {
+	DRM_MIPI_DBI_MODE_CONFIG_FUNCS,
+};
+
+static const struct drm_display_mode st7586_mode = {
+	DRM_SIMPLE_MODE(178, 128, 37, 27),
+};
+
+DEFINE_DRM_GEM_DMA_FOPS(st7586_fops);
+
+static const struct drm_driver st7586_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
+	.fops			= &st7586_fops,
+	DRM_GEM_DMA_DRIVER_OPS_VMAP,
+	DRM_FBDEV_DMA_DRIVER_OPS,
+	.debugfs_init		= mipi_dbi_debugfs_init,
+	.name			= "st7586",
+	.desc			= "Sitronix ST7586",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id st7586_of_match[] = {
+	{ .compatible = "lego,ev3-lcd" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, st7586_of_match);
+
+static const struct spi_device_id st7586_id[] = {
+	{ "ev3-lcd", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, st7586_id);
+
+static int st7586_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct st7586_device *st7586;
+	struct mipi_dbi_dev *dbidev;
+	struct drm_device *drm;
+	struct mipi_dbi *dbi;
+	struct gpio_desc *a0;
+	struct drm_plane *plane;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	struct drm_connector *connector;
+	u32 rotation = 0;
+	size_t bufsize;
+	int ret;
+
+	st7586 = devm_drm_dev_alloc(dev, &st7586_driver, struct st7586_device, dbidev.drm);
+	if (IS_ERR(st7586))
+		return PTR_ERR(st7586);
+	dbidev = &st7586->dbidev;
+	dbi = &dbidev->dbi;
+	drm = &dbidev->drm;
+
+	bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
+
+	dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(dbi->reset))
+		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
+
+	a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
+	if (IS_ERR(a0))
+		return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
+
+	device_property_read_u32(dev, "rotation", &rotation);
+
+	ret = mipi_dbi_spi_init(spi, dbi, a0);
+	if (ret)
+		return ret;
+
+	/*
+	 * Override value set by mipi_dbi_spi_init(). This driver is a bit
+	 * non-standard, so best to set it explicitly here.
+	 */
+	dbi->write_memory_bpw = 8;
+
+	/* Cannot read from this controller via SPI */
+	dbi->read_commands = NULL;
+
+	ret = drm_mipi_dbi_dev_init(dbidev, &st7586_mode, st7586_plane_formats[0],
+				    rotation, bufsize);
+	if (ret)
+		return ret;
+
+	ret = drmm_mode_config_init(drm);
+	if (ret)
+		return ret;
+
+	drm->mode_config.min_width = dbidev->mode.hdisplay;
+	drm->mode_config.max_width = dbidev->mode.hdisplay;
+	drm->mode_config.min_height = dbidev->mode.vdisplay;
+	drm->mode_config.max_height = dbidev->mode.vdisplay;
+	drm->mode_config.funcs = &st7586_mode_config_funcs;
+	drm->mode_config.preferred_depth = 24;
+	drm->mode_config.helper_private = &st7586_mode_config_helper_funcs;
+
+	plane = &st7586->plane;
+	ret = drm_universal_plane_init(drm, plane, 0, &st7586_plane_funcs,
+				       st7586_plane_formats, ARRAY_SIZE(st7586_plane_formats),
+				       st7586_plane_format_modifiers,
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret)
+		return ret;
+	drm_plane_helper_add(plane, &st7586_plane_helper_funcs);
+	drm_plane_enable_fb_damage_clips(plane);
+
+	crtc = &st7586->crtc;
+	ret = drm_crtc_init_with_planes(drm, crtc, plane, NULL, &st7586_crtc_funcs, NULL);
+	if (ret)
+		return ret;
+	drm_crtc_helper_add(crtc, &st7586_crtc_helper_funcs);
+
+	encoder = &st7586->encoder;
+	ret = drm_encoder_init(drm, encoder, &st7586_encoder_funcs, DRM_MODE_ENCODER_NONE, NULL);
+	if (ret)
+		return ret;
+	encoder->possible_crtcs = drm_crtc_mask(crtc);
+
+	connector = &st7586->connector;
+	ret = drm_connector_init(drm, connector, &st7586_connector_funcs,
+				 DRM_MODE_CONNECTOR_SPI);
+	if (ret)
+		return ret;
+	drm_connector_helper_add(connector, &st7586_connector_helper_funcs);
+
+	ret = drm_connector_attach_encoder(connector, encoder);
+	if (ret)
+		return ret;
+
+	drm_mode_config_reset(drm);
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, drm);
+
+	drm_client_setup(drm, NULL);
+
+	return 0;
+}
+
+static void st7586_remove(struct spi_device *spi)
+{
+	struct drm_device *drm = spi_get_drvdata(spi);
+
+	drm_dev_unplug(drm);
+	drm_atomic_helper_shutdown(drm);
+}
+
+static void st7586_shutdown(struct spi_device *spi)
+{
+	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
+}
+
+static struct spi_driver st7586_spi_driver = {
+	.driver = {
+		.name = "st7586",
+		.of_match_table = st7586_of_match,
+	},
+	.id_table = st7586_id,
+	.probe = st7586_probe,
+	.remove = st7586_remove,
+	.shutdown = st7586_shutdown,
+};
+module_spi_driver(st7586_spi_driver);
+
+MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
+MODULE_AUTHOR("David Lechner <david@lechnology.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/sitronix/st7735r.c b/drivers/gpu/drm/sitronix/st7735r.c
new file mode 100644
index 000000000..bd763871d
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7735r.c
@@ -0,0 +1,378 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DRM driver for display panels connected to a Sitronix ST7715R or ST7735R
+ * display controller in SPI mode.
+ *
+ * Copyright 2017 David Lechner <david@lechnology.com>
+ * Copyright (C) 2019 Glider bvba
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/dma-buf.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+#include <drm/clients/drm_client_setup.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fbdev_dma.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_dma_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_mipi_dbi.h>
+#include <drm/drm_print.h>
+
+#define ST7735R_FRMCTR1		0xb1
+#define ST7735R_FRMCTR2		0xb2
+#define ST7735R_FRMCTR3		0xb3
+#define ST7735R_INVCTR		0xb4
+#define ST7735R_PWCTR1		0xc0
+#define ST7735R_PWCTR2		0xc1
+#define ST7735R_PWCTR3		0xc2
+#define ST7735R_PWCTR4		0xc3
+#define ST7735R_PWCTR5		0xc4
+#define ST7735R_VMCTR1		0xc5
+#define ST7735R_GAMCTRP1	0xe0
+#define ST7735R_GAMCTRN1	0xe1
+
+#define ST7735R_MY	BIT(7)
+#define ST7735R_MX	BIT(6)
+#define ST7735R_MV	BIT(5)
+#define ST7735R_RGB	BIT(3)
+
+struct st7735r_cfg {
+	const struct drm_display_mode mode;
+	unsigned int left_offset;
+	unsigned int top_offset;
+	unsigned int write_only:1;
+	unsigned int rgb:1;		/* RGB (vs. BGR) */
+};
+
+struct st7735r_device {
+	struct mipi_dbi_dev dbidev;	/* Must be first for .release() */
+	const struct st7735r_cfg *cfg;
+
+	struct drm_plane plane;
+	struct drm_crtc crtc;
+	struct drm_encoder encoder;
+	struct drm_connector connector;
+};
+
+static struct st7735r_device *to_st7735r_device(struct drm_device *drm)
+{
+	return container_of(drm_to_mipi_dbi_dev(drm), struct st7735r_device, dbidev);
+}
+
+static const u32 st7735r_plane_formats[] = {
+	DRM_MIPI_DBI_PLANE_FORMATS,
+};
+
+static const u64 st7735r_plane_format_modifiers[] = {
+	DRM_MIPI_DBI_PLANE_FORMAT_MODIFIERS,
+};
+
+static const struct drm_plane_helper_funcs st7735r_plane_helper_funcs = {
+	DRM_MIPI_DBI_PLANE_HELPER_FUNCS,
+};
+
+static const struct drm_plane_funcs st7735r_plane_funcs = {
+	DRM_MIPI_DBI_PLANE_FUNCS,
+	.destroy = drm_plane_cleanup,
+};
+
+static void st7735r_crtc_helper_atomic_enable(struct drm_crtc *crtc,
+					      struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = crtc->dev;
+	struct st7735r_device *st7735r = to_st7735r_device(drm);
+	struct mipi_dbi_dev *dbidev = &st7735r->dbidev;
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	int ret, idx;
+	u8 addr_mode;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	DRM_DEBUG_KMS("\n");
+
+	ret = mipi_dbi_poweron_reset(dbidev);
+	if (ret)
+		goto out_exit;
+
+	msleep(150);
+
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	msleep(500);
+
+	mipi_dbi_command(dbi, ST7735R_FRMCTR1, 0x01, 0x2c, 0x2d);
+	mipi_dbi_command(dbi, ST7735R_FRMCTR2, 0x01, 0x2c, 0x2d);
+	mipi_dbi_command(dbi, ST7735R_FRMCTR3, 0x01, 0x2c, 0x2d, 0x01, 0x2c,
+			 0x2d);
+	mipi_dbi_command(dbi, ST7735R_INVCTR, 0x07);
+	mipi_dbi_command(dbi, ST7735R_PWCTR1, 0xa2, 0x02, 0x84);
+	mipi_dbi_command(dbi, ST7735R_PWCTR2, 0xc5);
+	mipi_dbi_command(dbi, ST7735R_PWCTR3, 0x0a, 0x00);
+	mipi_dbi_command(dbi, ST7735R_PWCTR4, 0x8a, 0x2a);
+	mipi_dbi_command(dbi, ST7735R_PWCTR5, 0x8a, 0xee);
+	mipi_dbi_command(dbi, ST7735R_VMCTR1, 0x0e);
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
+	switch (dbidev->rotation) {
+	default:
+		addr_mode = ST7735R_MX | ST7735R_MY;
+		break;
+	case 90:
+		addr_mode = ST7735R_MX | ST7735R_MV;
+		break;
+	case 180:
+		addr_mode = 0;
+		break;
+	case 270:
+		addr_mode = ST7735R_MY | ST7735R_MV;
+		break;
+	}
+
+	if (st7735r->cfg->rgb)
+		addr_mode |= ST7735R_RGB;
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT,
+			 MIPI_DCS_PIXEL_FMT_16BIT);
+	mipi_dbi_command(dbi, ST7735R_GAMCTRP1, 0x02, 0x1c, 0x07, 0x12, 0x37,
+			 0x32, 0x29, 0x2d, 0x29, 0x25, 0x2b, 0x39, 0x00, 0x01,
+			 0x03, 0x10);
+	mipi_dbi_command(dbi, ST7735R_GAMCTRN1, 0x03, 0x1d, 0x07, 0x06, 0x2e,
+			 0x2c, 0x29, 0x2d, 0x2e, 0x2e, 0x37, 0x3f, 0x00, 0x00,
+			 0x02, 0x10);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+
+	msleep(100);
+
+	mipi_dbi_command(dbi, MIPI_DCS_ENTER_NORMAL_MODE);
+
+	msleep(20);
+
+	backlight_enable(dbidev->backlight);
+out_exit:
+	drm_dev_exit(idx);
+}
+
+static const struct drm_crtc_helper_funcs st7735r_crtc_helper_funcs = {
+	DRM_MIPI_DBI_CRTC_HELPER_FUNCS,
+	.atomic_enable = st7735r_crtc_helper_atomic_enable,
+};
+
+static const struct drm_crtc_funcs st7735r_crtc_funcs = {
+	DRM_MIPI_DBI_CRTC_FUNCS,
+	.destroy = drm_crtc_cleanup,
+};
+
+static const struct drm_encoder_funcs st7735r_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static const struct drm_connector_helper_funcs st7735r_connector_helper_funcs = {
+	DRM_MIPI_DBI_CONNECTOR_HELPER_FUNCS,
+};
+
+static const struct drm_connector_funcs st7735r_connector_funcs = {
+	DRM_MIPI_DBI_CONNECTOR_FUNCS,
+	.destroy = drm_connector_cleanup,
+};
+
+static const struct drm_mode_config_helper_funcs st7735r_mode_config_helper_funcs = {
+	DRM_MIPI_DBI_MODE_CONFIG_HELPER_FUNCS,
+};
+
+static const struct drm_mode_config_funcs st7735r_mode_config_funcs = {
+	DRM_MIPI_DBI_MODE_CONFIG_FUNCS,
+};
+
+static const struct st7735r_cfg jd_t18003_t01_cfg = {
+	.mode		= { DRM_SIMPLE_MODE(128, 160, 28, 35) },
+	/* Cannot read from Adafruit 1.8" display via SPI */
+	.write_only	= true,
+};
+
+static const struct st7735r_cfg rh128128t_cfg = {
+	.mode		= { DRM_SIMPLE_MODE(128, 128, 25, 26) },
+	.left_offset	= 2,
+	.top_offset	= 3,
+	.rgb		= true,
+};
+
+DEFINE_DRM_GEM_DMA_FOPS(st7735r_fops);
+
+static const struct drm_driver st7735r_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
+	.fops			= &st7735r_fops,
+	DRM_GEM_DMA_DRIVER_OPS_VMAP,
+	DRM_FBDEV_DMA_DRIVER_OPS,
+	.debugfs_init		= mipi_dbi_debugfs_init,
+	.name			= "st7735r",
+	.desc			= "Sitronix ST7735R",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id st7735r_of_match[] = {
+	{ .compatible = "jianda,jd-t18003-t01", .data = &jd_t18003_t01_cfg },
+	{ .compatible = "okaya,rh128128t", .data = &rh128128t_cfg },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, st7735r_of_match);
+
+static const struct spi_device_id st7735r_id[] = {
+	{ "jd-t18003-t01", (uintptr_t)&jd_t18003_t01_cfg },
+	{ "rh128128t", (uintptr_t)&rh128128t_cfg },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, st7735r_id);
+
+static int st7735r_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	const struct st7735r_cfg *cfg;
+	struct mipi_dbi_dev *dbidev;
+	struct st7735r_device *st7735r;
+	struct drm_device *drm;
+	struct mipi_dbi *dbi;
+	struct gpio_desc *dc;
+	struct drm_plane *plane;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	struct drm_connector *connector;
+	u32 rotation = 0;
+	int ret;
+
+	cfg = device_get_match_data(&spi->dev);
+	if (!cfg)
+		cfg = (void *)spi_get_device_id(spi)->driver_data;
+
+	st7735r = devm_drm_dev_alloc(dev, &st7735r_driver, struct st7735r_device, dbidev.drm);
+	if (IS_ERR(st7735r))
+		return PTR_ERR(st7735r);
+
+	dbidev = &st7735r->dbidev;
+	st7735r->cfg = cfg;
+
+	dbi = &dbidev->dbi;
+	drm = &dbidev->drm;
+
+	dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(dbi->reset))
+		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
+
+	dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW);
+	if (IS_ERR(dc))
+		return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
+
+	dbidev->backlight = devm_of_find_backlight(dev);
+	if (IS_ERR(dbidev->backlight))
+		return PTR_ERR(dbidev->backlight);
+
+	device_property_read_u32(dev, "rotation", &rotation);
+
+	ret = mipi_dbi_spi_init(spi, dbi, dc);
+	if (ret)
+		return ret;
+
+	if (cfg->write_only)
+		dbi->read_commands = NULL;
+
+	dbidev->left_offset = cfg->left_offset;
+	dbidev->top_offset = cfg->top_offset;
+
+	ret = drm_mipi_dbi_dev_init(dbidev, &cfg->mode, st7735r_plane_formats[0], rotation, 0);
+	if (ret)
+		return ret;
+
+	ret = drmm_mode_config_init(drm);
+	if (ret)
+		return ret;
+
+	drm->mode_config.min_width = dbidev->mode.hdisplay;
+	drm->mode_config.max_width = dbidev->mode.hdisplay;
+	drm->mode_config.min_height = dbidev->mode.vdisplay;
+	drm->mode_config.max_height = dbidev->mode.vdisplay;
+	drm->mode_config.funcs = &st7735r_mode_config_funcs;
+	drm->mode_config.preferred_depth = 16;
+	drm->mode_config.helper_private = &st7735r_mode_config_helper_funcs;
+
+	plane = &st7735r->plane;
+	ret = drm_universal_plane_init(drm, plane, 0, &st7735r_plane_funcs,
+				       st7735r_plane_formats, ARRAY_SIZE(st7735r_plane_formats),
+				       st7735r_plane_format_modifiers,
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret)
+		return ret;
+	drm_plane_helper_add(plane, &st7735r_plane_helper_funcs);
+	drm_plane_enable_fb_damage_clips(plane);
+
+	crtc = &st7735r->crtc;
+	ret = drm_crtc_init_with_planes(drm, crtc, plane, NULL, &st7735r_crtc_funcs, NULL);
+	if (ret)
+		return ret;
+	drm_crtc_helper_add(crtc, &st7735r_crtc_helper_funcs);
+
+	encoder = &st7735r->encoder;
+	ret = drm_encoder_init(drm, encoder, &st7735r_encoder_funcs, DRM_MODE_ENCODER_NONE, NULL);
+	if (ret)
+		return ret;
+	encoder->possible_crtcs = drm_crtc_mask(crtc);
+
+	connector = &st7735r->connector;
+	ret = drm_connector_init(drm, connector, &st7735r_connector_funcs,
+				 DRM_MODE_CONNECTOR_SPI);
+	if (ret)
+		return ret;
+	drm_connector_helper_add(connector, &st7735r_connector_helper_funcs);
+
+	ret = drm_connector_attach_encoder(connector, encoder);
+	if (ret)
+		return ret;
+
+	drm_mode_config_reset(drm);
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, drm);
+
+	drm_client_setup(drm, NULL);
+
+	return 0;
+}
+
+static void st7735r_remove(struct spi_device *spi)
+{
+	struct drm_device *drm = spi_get_drvdata(spi);
+
+	drm_dev_unplug(drm);
+	drm_atomic_helper_shutdown(drm);
+}
+
+static void st7735r_shutdown(struct spi_device *spi)
+{
+	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
+}
+
+static struct spi_driver st7735r_spi_driver = {
+	.driver = {
+		.name = "st7735r",
+		.of_match_table = st7735r_of_match,
+	},
+	.id_table = st7735r_id,
+	.probe = st7735r_probe,
+	.remove = st7735r_remove,
+	.shutdown = st7735r_shutdown,
+};
+module_spi_driver(st7735r_spi_driver);
+
+MODULE_DESCRIPTION("Sitronix ST7735R DRM driver");
+MODULE_AUTHOR("David Lechner <david@lechnology.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/sitronix/st7920.c b/drivers/gpu/drm/sitronix/st7920.c
new file mode 100644
index 000000000..d32039180
--- /dev/null
+++ b/drivers/gpu/drm/sitronix/st7920.c
@@ -0,0 +1,867 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DRM driver for Sitronix ST7920 LCD displays
+ *
+ * Copyright 2025 Iker Pedrosa <ikerpedrosam@gmail.com>
+ *
+ */
+
+#include <linux/bitrev.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include <drm/clients/drm_client_setup.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fbdev_shmem.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_plane.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+
+#define DRIVER_NAME	"sitronix_st7920"
+#define DRIVER_DESC	"DRM driver for Sitronix ST7920 LCD displays"
+#define DRIVER_MAJOR	1
+#define DRIVER_MINOR	0
+
+/* Display organization */
+#define ST7920_PITCH		16
+#define ST7920_SCANLINES	64
+#define BYTES_IN_DISPLAY	(ST7920_PITCH * ST7920_SCANLINES)
+#define BYTES_IN_SEGMENT	2
+#define PIXELS_PER_SEGMENT	(BYTES_IN_SEGMENT * 8)
+#define ST7920_DEFAULT_WIDTH	128
+#define ST7920_DEFAULT_HEIGHT	64
+
+/* Sync sequence */
+#define SYNC_BITS			0xF8
+#define RW_HIGH				0x04
+#define RS_HIGH				0x02
+
+/* Commands */
+#define SET_DISPLAY_ON			0x0C
+#define SET_DISPLAY_OFF			0x08
+#define SET_DISPLAY_CLEAR		0x01
+#define SET_BASIC_INSTRUCTION_SET	0x30
+#define SET_EXT_INSTRUCTION_SET		0x34
+#define SET_GRAPHICS_DISPLAY		0x36
+#define SET_GDRAM_ADDRESS		0x80
+#define SET_GDRAM_DATA			0xFF /* Driver internal command */
+
+/* Masks */
+#define HIGH_DATA_MASK			0xF0
+#define LOW_DATA_MASK			0x0F
+#define TOP_VERTICAL_ADDRESS		0x80
+#define BOTTOM_VERTICAL_ADDRESS		0x60
+#define TOP_HORIZONTAL_ADDRESS		0x00
+#define BOTTOM_HORIZONTAL_ADDRESS	0x80
+
+#define CMD_SIZE			35
+
+struct spi7920_error {
+	int errno;
+};
+
+struct st7920_device {
+	struct drm_device drm;
+	struct drm_display_mode mode;
+	struct drm_plane primary_plane;
+	struct drm_crtc crtc;
+	struct drm_encoder encoder;
+	struct drm_connector connector;
+	struct spi_device *spi;
+
+	struct regmap *regmap;
+
+	struct gpio_desc *reset_gpio;
+
+	u32 height;
+	u32 width;
+};
+
+struct st7920_plane_state {
+	struct drm_shadow_plane_state base;
+	/* Intermediate buffer to convert pixels from XRGB8888 to HW format */
+	u8 *buffer;
+};
+
+struct st7920_crtc_state {
+	struct drm_crtc_state base;
+	/* Buffer to store pixels in HW format and written to the panel */
+	u8 *data_array;
+};
+
+static inline struct st7920_plane_state *to_st7920_plane_state(struct drm_plane_state *state)
+{
+	return container_of(state, struct st7920_plane_state, base.base);
+}
+
+static inline struct st7920_crtc_state *to_st7920_crtc_state(struct drm_crtc_state *state)
+{
+	return container_of(state, struct st7920_crtc_state, base);
+}
+
+static inline struct st7920_device *drm_to_st7920(struct drm_device *drm)
+{
+	return container_of(drm, struct st7920_device, drm);
+}
+
+static int st7920_store_gdram_address(const void *data, u8 *reg)
+{
+	const u8 y_addr = *(const u8 *)data;
+	bool bottom_screen = (y_addr >= 32);
+	int i = 0;
+
+	reg[i++] = SYNC_BITS;
+	/* Set vertical address */
+	if (!bottom_screen)
+		reg[i++] = TOP_VERTICAL_ADDRESS + (*(uint8_t *)data & HIGH_DATA_MASK);
+	else
+		reg[i++] = BOTTOM_VERTICAL_ADDRESS + (*(uint8_t *)data & HIGH_DATA_MASK);
+
+	reg[i++] = *(uint8_t *)data << 4;
+	/* Set horizontal address */
+	reg[i++] = SET_GDRAM_ADDRESS;
+	if (!bottom_screen)
+		reg[i++] = TOP_HORIZONTAL_ADDRESS;
+	else
+		reg[i++] = BOTTOM_HORIZONTAL_ADDRESS;
+
+	return i;
+}
+
+static int st7920_store_gdram_data(const void *data, u8 *reg)
+{
+	const u8 *line_data = data;
+	int i = 0, j = 0;
+
+	reg[i++] = SYNC_BITS | RS_HIGH;
+
+	for (j = 0; j < 16; j++) {
+		reg[i++] = line_data[j] & 0xF0;
+		reg[i++] = (line_data[j] << 4) & 0xF0;
+	}
+
+	return i;
+}
+
+static int st7920_store_others(int cmd, const void *data, u8 *reg)
+{
+	int i = 0;
+
+	reg[i++] = SYNC_BITS;
+	reg[i++] = cmd & HIGH_DATA_MASK;
+	reg[i++] = (cmd & LOW_DATA_MASK) << 4;
+
+	return i;
+}
+
+static void st7920_spi_write(struct spi_device *spi, int cmd, const void *data,
+			     int delay_us, struct spi7920_error *err)
+{
+	u8 reg[CMD_SIZE] = {0};
+	int size = 0;
+	int ret;
+
+	if (err->errno)
+		return;
+
+	/*
+	 * First the sync bits are sent: 11111WS0.
+	 * Where W is the read/write (RW) bit and S is the register/data (RS) bit.
+	 * Then, every 8 bits instruction/data will be separated into 2 groups.
+	 * Higher 4 bits (DB7~DB4) will be placed in the first section followed by
+	 * 4 '0's. And lower 4 bits (DB3~DB0) will be placed in the second section
+	 * followed by 4 '0's.
+	 */
+	if (cmd == SET_GDRAM_ADDRESS)
+		size = st7920_store_gdram_address(data, reg);
+	else if (cmd == SET_GDRAM_DATA)
+		size = st7920_store_gdram_data(data, reg);
+	else
+		size = st7920_store_others(cmd, data, reg);
+
+	ret = spi_write(spi, reg, size);
+	if (ret) {
+		err->errno = ret;
+		return;
+	}
+
+	if (delay_us)
+		udelay(delay_us);
+}
+
+static const struct regmap_config st7920_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static const struct of_device_id st7920_of_match[] = {
+	/* st7920 family */
+	{
+		.compatible = "sitronix,st7920",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, st7920_of_match);
+
+/*
+ * The SPI core always reports a MODALIAS uevent of the form "spi:<dev>", even
+ * if the device was registered via OF. This means that the module will not be
+ * auto loaded, unless it contains an alias that matches the MODALIAS reported.
+ *
+ * To workaround this issue, add a SPI device ID table. Even when this should
+ * not be needed for this driver to match the registered SPI devices.
+ */
+static const struct spi_device_id st7920_spi_id[] = {
+	/* st7920 family */
+	{ "st7920",  0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, st7920_spi_id);
+
+static void st7920_power_on(struct st7920_device *st7920,
+			    struct spi7920_error *err)
+{
+	st7920_spi_write(st7920->spi, SET_DISPLAY_ON, NULL, 72, err);
+}
+
+static void st7920_power_off(struct st7920_device *st7920,
+			     struct spi7920_error *err)
+{
+	st7920_spi_write(st7920->spi, SET_DISPLAY_CLEAR, NULL, 1600, err);
+	st7920_spi_write(st7920->spi, SET_DISPLAY_OFF, NULL, 72, err);
+}
+
+static void st7920_hw_reset(struct st7920_device *st7920)
+{
+	if (!st7920->reset_gpio)
+		return;
+
+	gpiod_set_value_cansleep(st7920->reset_gpio, 1);
+	usleep_range(15, 20);
+	gpiod_set_value_cansleep(st7920->reset_gpio, 0);
+	msleep(40);
+}
+
+static int st7920_init(struct st7920_device *st7920)
+{
+	struct spi7920_error err = {0};
+
+	st7920_spi_write(st7920->spi, SET_BASIC_INSTRUCTION_SET, NULL, 72, &err);
+	st7920_power_on(st7920, &err);
+	st7920_spi_write(st7920->spi, SET_GRAPHICS_DISPLAY, NULL, 72, &err);
+	st7920_spi_write(st7920->spi, SET_DISPLAY_CLEAR, NULL, 1600, &err);
+
+	return err.errno;
+}
+
+static int st7920_update_rect(struct st7920_device *st7920,
+			      struct drm_rect *rect, u8 *buf,
+			      u8 *data_array)
+{
+	struct spi7920_error err = {0};
+	u32 array_idx = 0;
+	int i, j;
+
+	/*
+	 * The screen is divided in 64(Y)x8(X) segments and each segment is
+	 * further divided in 2 bytes (D15~D0).
+	 *
+	 * Segment 0x0 is in the top-right corner, while segment 63x15 is in the
+	 * bottom-left. They would be displayed in the screen in the following way:
+	 * 0x0  0x1  0x2  ... 0x15
+	 * 1x0  1x1  1x2  ... 1x15
+	 * ...
+	 * 63x0 63x1 63x2 ... 63x15
+	 *
+	 * The data in each byte is big endian.
+	 */
+
+	for (i = 0; i < ST7920_SCANLINES; i++) {
+		u8 *line_start = buf + (i * ST7920_PITCH);
+		u8 line_buffer[ST7920_PITCH];
+
+		for (j = 0; j < ST7920_PITCH; j++) {
+			line_buffer[j] = bitrev8(line_start[j]);
+			data_array[array_idx++] = line_buffer[j];
+		}
+
+		st7920_spi_write(st7920->spi, SET_GDRAM_ADDRESS, &i, 72, &err);
+		st7920_spi_write(st7920->spi, SET_GDRAM_DATA, line_buffer, 72, &err);
+	}
+
+	return err.errno;
+}
+
+static void st7920_clear_screen(struct st7920_device *st7920, u8 *data_array)
+{
+	struct spi7920_error err = {0};
+
+	memset(data_array, 0, BYTES_IN_DISPLAY);
+
+	st7920_spi_write(st7920->spi, SET_DISPLAY_CLEAR, NULL, 1600, &err);
+}
+
+static int st7920_fb_blit_rect(struct drm_framebuffer *fb,
+			       const struct iosys_map *vmap,
+			       struct drm_rect *rect,
+			       u8 *buf, u8 *data_array,
+			       struct drm_format_conv_state *fmtcnv_state)
+{
+	struct st7920_device *st7920 = drm_to_st7920(fb->dev);
+	struct iosys_map dst;
+	unsigned int dst_pitch;
+	int ret;
+
+	/* Align y to display page boundaries */
+	rect->y1 = round_down(rect->y1, PIXELS_PER_SEGMENT);
+	rect->y2 = min_t(unsigned int, round_up(rect->y2, PIXELS_PER_SEGMENT), st7920->height);
+
+	dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 8);
+
+	iosys_map_set_vaddr(&dst, buf);
+	drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, vmap, fb, rect, fmtcnv_state);
+
+	ret = st7920_update_rect(st7920, rect, buf, data_array);
+
+	return ret;
+}
+
+static int st7920_primary_plane_atomic_check(struct drm_plane *plane,
+					     struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = plane->dev;
+	struct st7920_device *st7920 = drm_to_st7920(drm);
+	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct st7920_plane_state *st7920_state = to_st7920_plane_state(plane_state);
+	struct drm_shadow_plane_state *shadow_plane_state = &st7920_state->base;
+	struct drm_crtc *crtc = plane_state->crtc;
+	struct drm_crtc_state *crtc_state = NULL;
+	const struct drm_format_info *fi;
+	unsigned int pitch;
+	int ret;
+
+	if (crtc)
+		crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+
+	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
+						  DRM_PLANE_NO_SCALING,
+						  DRM_PLANE_NO_SCALING,
+						  false, false);
+	if (ret)
+		return ret;
+	else if (!plane_state->visible)
+		return 0;
+
+	fi = drm_format_info(DRM_FORMAT_R1);
+	if (!fi)
+		return -EINVAL;
+
+	pitch = drm_format_info_min_pitch(fi, 0, st7920->width);
+
+	if (plane_state->fb->format != fi) {
+		void *buf;
+
+		/* format conversion necessary; reserve buffer */
+		buf = drm_format_conv_state_reserve(&shadow_plane_state->fmtcnv_state,
+						    pitch, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+	}
+
+	st7920_state->buffer = kcalloc(pitch, st7920->height, GFP_KERNEL);
+	if (!st7920_state->buffer)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void st7920_primary_plane_atomic_update(struct drm_plane *plane,
+					       struct drm_atomic_commit *state)
+{
+	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
+	struct st7920_crtc_state *st7920_crtc_state =  to_st7920_crtc_state(crtc_state);
+	struct st7920_plane_state *st7920_plane_state = to_st7920_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 dst_clip;
+	struct drm_rect damage;
+	int idx;
+	int ret;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	if (drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE) == 0) {
+		drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
+		drm_atomic_for_each_plane_damage(&iter, &damage) {
+			dst_clip = plane_state->dst;
+
+			if (!drm_rect_intersect(&dst_clip, &damage))
+				continue;
+
+			ret = st7920_fb_blit_rect(fb, &shadow_plane_state->data[0], &dst_clip,
+						  st7920_plane_state->buffer,
+						  st7920_crtc_state->data_array,
+						  &shadow_plane_state->fmtcnv_state);
+			if (ret)
+				drm_err_once(plane->dev, "Failed to write to device: %d.\n", ret);
+		}
+
+		drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
+	}
+
+	drm_dev_exit(idx);
+}
+
+static void st7920_primary_plane_atomic_disable(struct drm_plane *plane,
+						struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = plane->dev;
+	struct st7920_device *st7920 = drm_to_st7920(drm);
+	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_crtc_state *crtc_state;
+	struct st7920_crtc_state *st7920_crtc_state;
+	int idx;
+
+	if (!plane_state->crtc)
+		return;
+
+	crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
+	st7920_crtc_state = to_st7920_crtc_state(crtc_state);
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	st7920_clear_screen(st7920, st7920_crtc_state->data_array);
+
+	drm_dev_exit(idx);
+}
+
+/* Called during init to allocate the plane's atomic state. */
+static void st7920_primary_plane_reset(struct drm_plane *plane)
+{
+	struct st7920_plane_state *st7920_state;
+
+	drm_WARN_ON_ONCE(plane->dev, plane->state);
+
+	st7920_state = kzalloc_obj(*st7920_state);
+	if (!st7920_state)
+		return;
+
+	__drm_gem_reset_shadow_plane(plane, &st7920_state->base);
+}
+
+static struct drm_plane_state *st7920_primary_plane_duplicate_state(struct drm_plane *plane)
+{
+	struct drm_shadow_plane_state *new_shadow_plane_state;
+	struct st7920_plane_state *st7920_state;
+
+	if (drm_WARN_ON_ONCE(plane->dev, !plane->state))
+		return NULL;
+
+	st7920_state = kzalloc_obj(*st7920_state);
+	if (!st7920_state)
+		return NULL;
+
+	new_shadow_plane_state = &st7920_state->base;
+
+	__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
+
+	return &new_shadow_plane_state->base;
+}
+
+static void st7920_primary_plane_destroy_state(struct drm_plane *plane,
+					       struct drm_plane_state *state)
+{
+	struct st7920_plane_state *st7920_state = to_st7920_plane_state(state);
+
+	kfree(st7920_state->buffer);
+
+	__drm_gem_destroy_shadow_plane_state(&st7920_state->base);
+
+	kfree(st7920_state);
+}
+
+static const struct drm_plane_helper_funcs st7920_primary_plane_helper_funcs = {
+	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+	.atomic_check = st7920_primary_plane_atomic_check,
+	.atomic_update = st7920_primary_plane_atomic_update,
+	.atomic_disable = st7920_primary_plane_atomic_disable,
+};
+
+static const struct drm_plane_funcs st7920_primary_plane_funcs = {
+	.update_plane = drm_atomic_helper_update_plane,
+	.disable_plane = drm_atomic_helper_disable_plane,
+	.reset = st7920_primary_plane_reset,
+	.atomic_duplicate_state = st7920_primary_plane_duplicate_state,
+	.atomic_destroy_state = st7920_primary_plane_destroy_state,
+	.destroy = drm_plane_cleanup,
+};
+
+static enum drm_mode_status st7920_crtc_mode_valid(struct drm_crtc *crtc,
+						   const struct drm_display_mode *mode)
+{
+	struct st7920_device *st7920 = drm_to_st7920(crtc->dev);
+
+	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &st7920->mode);
+}
+
+static int st7920_crtc_atomic_check(struct drm_crtc *crtc,
+				    struct drm_atomic_commit *state)
+{
+	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+	struct st7920_crtc_state *st7920_state = to_st7920_crtc_state(crtc_state);
+	int ret;
+
+	ret = drm_crtc_helper_atomic_check(crtc, state);
+	if (ret)
+		return ret;
+
+	st7920_state->data_array = kmalloc(BYTES_IN_DISPLAY, GFP_KERNEL);
+	if (!st7920_state->data_array)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void st7920_crtc_atomic_enable(struct drm_crtc *crtc,
+				      struct drm_atomic_commit *state)
+{
+	struct drm_device *drm = crtc->dev;
+	struct st7920_device *st7920 = drm_to_st7920(drm);
+	int idx;
+	int ret;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	st7920_hw_reset(st7920);
+
+	ret = st7920_init(st7920);
+	if (ret)
+		drm_err(drm, "Failed to init hardware: %d\n", ret);
+
+	drm_dev_exit(idx);
+}
+
+static void st7920_crtc_atomic_disable(struct drm_crtc *crtc,
+				       struct drm_atomic_commit *state)
+{
+	struct spi7920_error err = {0};
+	struct drm_device *drm = crtc->dev;
+	struct st7920_device *st7920 = drm_to_st7920(drm);
+	int idx;
+
+	drm_dev_enter(drm, &idx);
+
+	st7920_power_off(st7920, &err);
+
+	drm_dev_exit(idx);
+}
+
+/* Called during init to allocate the CRTC's atomic state. */
+static void st7920_crtc_reset(struct drm_crtc *crtc)
+{
+	struct st7920_crtc_state *st7920_state;
+
+	drm_WARN_ON_ONCE(crtc->dev, crtc->state);
+
+	st7920_state = kzalloc_obj(*st7920_state);
+	if (!st7920_state)
+		return;
+
+	__drm_atomic_helper_crtc_reset(crtc, &st7920_state->base);
+}
+
+static struct drm_crtc_state *st7920_crtc_duplicate_state(struct drm_crtc *crtc)
+{
+	struct st7920_crtc_state *st7920_state;
+
+	if (drm_WARN_ON_ONCE(crtc->dev, !crtc->state))
+		return NULL;
+
+	st7920_state = kzalloc_obj(*st7920_state);
+	if (!st7920_state)
+		return NULL;
+
+	__drm_atomic_helper_crtc_duplicate_state(crtc, &st7920_state->base);
+
+	return &st7920_state->base;
+}
+
+static void st7920_crtc_destroy_state(struct drm_crtc *crtc,
+				      struct drm_crtc_state *state)
+{
+	struct st7920_crtc_state *st7920_state = to_st7920_crtc_state(state);
+
+	kfree(st7920_state->data_array);
+
+	__drm_atomic_helper_crtc_destroy_state(state);
+
+	kfree(st7920_state);
+}
+
+/*
+ * The CRTC is always enabled. Screen updates are performed by
+ * the primary plane's atomic_update function. Disabling clears
+ * the screen in the primary plane's atomic_disable function.
+ */
+static const struct drm_crtc_helper_funcs st7920_crtc_helper_funcs = {
+	.mode_valid = st7920_crtc_mode_valid,
+	.atomic_check = st7920_crtc_atomic_check,
+	.atomic_enable = st7920_crtc_atomic_enable,
+	.atomic_disable = st7920_crtc_atomic_disable,
+};
+
+static const struct drm_crtc_funcs st7920_crtc_funcs = {
+	.reset = st7920_crtc_reset,
+	.destroy = drm_crtc_cleanup,
+	.set_config = drm_atomic_helper_set_config,
+	.page_flip = drm_atomic_helper_page_flip,
+	.atomic_duplicate_state = st7920_crtc_duplicate_state,
+	.atomic_destroy_state = st7920_crtc_destroy_state,
+};
+
+static const struct drm_encoder_funcs st7920_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static int st7920_connector_get_modes(struct drm_connector *connector)
+{
+	struct st7920_device *st7920 = drm_to_st7920(connector->dev);
+
+	return drm_connector_helper_get_modes_fixed(connector, &st7920->mode);
+}
+
+static const struct drm_connector_helper_funcs st7920_connector_helper_funcs = {
+	.get_modes = st7920_connector_get_modes,
+};
+
+static const struct drm_connector_funcs st7920_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 st7920_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 uint32_t st7920_formats[] = {
+	DRM_FORMAT_XRGB8888,
+};
+
+DEFINE_DRM_GEM_FOPS(st7920_fops);
+
+static const struct drm_driver st7920_drm_driver = {
+	DRM_GEM_SHMEM_DRIVER_OPS,
+	DRM_FBDEV_SHMEM_DRIVER_OPS,
+	.name			= DRIVER_NAME,
+	.desc			= DRIVER_DESC,
+	.major			= DRIVER_MAJOR,
+	.minor			= DRIVER_MINOR,
+	.driver_features = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
+	.fops			= &st7920_fops,
+};
+
+static int st7920_init_modeset(struct st7920_device *st7920)
+{
+	struct drm_display_mode *mode = &st7920->mode;
+	struct drm_device *drm = &st7920->drm;
+	unsigned long max_width, max_height;
+	struct drm_plane *primary_plane;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	struct drm_connector *connector;
+	int ret;
+
+	/*
+	 * Modesetting
+	 */
+
+	ret = drmm_mode_config_init(drm);
+	if (ret) {
+		drm_err(drm, "DRM mode config init failed: %d\n", ret);
+		return ret;
+	}
+
+	mode->type = DRM_MODE_TYPE_DRIVER;
+	mode->clock = 30;
+	mode->hdisplay = st7920->width;
+	mode->htotal = st7920->width;
+	mode->hsync_start = st7920->width;
+	mode->hsync_end = st7920->width;
+	mode->vdisplay = st7920->height;
+	mode->vtotal = st7920->height;
+	mode->vsync_start = st7920->height;
+	mode->vsync_end = st7920->height;
+	mode->width_mm = 27;
+	mode->height_mm = 27;
+
+	max_width = max_t(unsigned long, mode->hdisplay, DRM_SHADOW_PLANE_MAX_WIDTH);
+	max_height = max_t(unsigned long, mode->vdisplay, DRM_SHADOW_PLANE_MAX_HEIGHT);
+
+	drm->mode_config.min_width = mode->hdisplay;
+	drm->mode_config.max_width = max_width;
+	drm->mode_config.min_height = mode->vdisplay;
+	drm->mode_config.max_height = max_height;
+	drm->mode_config.preferred_depth = 24;
+	drm->mode_config.funcs = &st7920_mode_config_funcs;
+
+	/* Primary plane */
+
+	primary_plane = &st7920->primary_plane;
+	ret = drm_universal_plane_init(drm, primary_plane, 0, &st7920_primary_plane_funcs,
+				       st7920_formats, ARRAY_SIZE(st7920_formats),
+				       NULL, DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret) {
+		drm_err(drm, "DRM primary plane init failed: %d\n", ret);
+		return ret;
+	}
+
+	drm_plane_helper_add(primary_plane, &st7920_primary_plane_helper_funcs);
+
+	drm_plane_enable_fb_damage_clips(primary_plane);
+
+	/* CRTC */
+
+	crtc = &st7920->crtc;
+	ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
+					&st7920_crtc_funcs, NULL);
+	if (ret) {
+		drm_err(drm, "DRM crtc init failed: %d\n", ret);
+		return ret;
+	}
+
+	drm_crtc_helper_add(crtc, &st7920_crtc_helper_funcs);
+
+	/* Encoder */
+
+	encoder = &st7920->encoder;
+	ret = drm_encoder_init(drm, encoder, &st7920_encoder_funcs,
+			       DRM_MODE_ENCODER_NONE, NULL);
+	if (ret) {
+		drm_err(drm, "DRM encoder init failed: %d\n", ret);
+		return ret;
+	}
+
+	encoder->possible_crtcs = drm_crtc_mask(crtc);
+
+	/* Connector */
+
+	connector = &st7920->connector;
+	ret = drm_connector_init(drm, connector, &st7920_connector_funcs,
+				 DRM_MODE_CONNECTOR_Unknown);
+	if (ret) {
+		drm_err(drm, "DRM connector init failed: %d\n", ret);
+		return ret;
+	}
+
+	drm_connector_helper_add(connector, &st7920_connector_helper_funcs);
+
+	ret = drm_connector_attach_encoder(connector, encoder);
+	if (ret) {
+		drm_err(drm, "DRM attach connector to encoder failed: %d\n", ret);
+		return ret;
+	}
+
+	drm_mode_config_reset(drm);
+
+	return 0;
+}
+
+static int st7920_probe(struct spi_device *spi)
+{
+	struct st7920_device *st7920;
+	struct regmap *regmap;
+	struct device *dev = &spi->dev;
+	struct drm_device *drm;
+	int ret;
+
+	regmap = devm_regmap_init_spi(spi, &st7920_spi_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	st7920 = devm_drm_dev_alloc(dev, &st7920_drm_driver,
+				    struct st7920_device, drm);
+	if (IS_ERR(st7920))
+		return PTR_ERR(st7920);
+
+	drm = &st7920->drm;
+
+	st7920->drm.dev = dev;
+	st7920->regmap = regmap;
+	st7920->spi = spi;
+	st7920->width = ST7920_DEFAULT_WIDTH;
+	st7920->height = ST7920_DEFAULT_HEIGHT;
+
+	st7920->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(st7920->reset_gpio)) {
+		ret = PTR_ERR(st7920->reset_gpio);
+		return dev_err_probe(dev, ret, "Unable to retrieve reset GPIO\n");
+	}
+
+	spi_set_drvdata(spi, st7920);
+
+	ret = st7920_init_modeset(st7920);
+	if (ret)
+		return ret;
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		return dev_err_probe(dev, ret, "DRM device register failed\n");
+
+	drm_client_setup(drm, NULL);
+
+	return 0;
+}
+
+static void st7920_remove(struct spi_device *spi)
+{
+	struct st7920_device *st7920 = spi_get_drvdata(spi);
+
+	drm_dev_unplug(&st7920->drm);
+	drm_atomic_helper_shutdown(&st7920->drm);
+}
+
+static void st7920_shutdown(struct spi_device *spi)
+{
+	struct st7920_device *st7920 = spi_get_drvdata(spi);
+
+	drm_atomic_helper_shutdown(&st7920->drm);
+}
+
+static struct spi_driver st7920_spi_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = st7920_of_match,
+	},
+	.id_table = st7920_spi_id,
+	.probe = st7920_probe,
+	.remove = st7920_remove,
+	.shutdown = st7920_shutdown,
+};
+module_spi_driver(st7920_spi_driver);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Iker Pedrosa <ipedrosam@gmail.com>");
+MODULE_LICENSE("GPL");