DRM driver for ILI9225 display panels

This adds the vendor prefix ilitek for ILI Technology Corporation (ILITEK).

This prefix is already used several places and I will be adding more.

Signed-off-by David Lechner <[email protected]>

---

v2 changes:
* New patch in v2

 Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
 1 file changed, 1 insertion(+)

This adds the vendor prefix ilitek for ILI Technology Corporation (ILITEK).

This prefix is already used several places and I will be adding more.

Signed-off-by David Lechner <david-nq/r/kbU++upp/[email protected]>

---

v2 changes:
* New patch in v2

This adds a new binding for display panels that use an Ilitek ILI9225 controller.

The "ilitek,ili9225-2.2in-176x220" device listed has no identification markings whatsoever and an hour of googling turned up nothing, hence the use of the size and resolution in the name instead of a model name.

An example of this nameless device can be found at:
https://github.com/Nkawu/TFT_22_ILI9225

Signed-off-by David Lechner <[email protected]>

---

v2 changes:
* renamed compatible string based on feedback

 .../devicetree/bindings/display/ilitek,ili9225.txt | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/ilitek,ili9225.txt

This exports the mipi_dbi_buf_copy() and mipi_dbi_spi_cmd_max_speed() functions so that they can be shared with other drivers.

Signed-off-by David Lechner <david-nq/r/kbU++upp/[email protected]>

---

v2 changes:
* new patch in v2

  drivers/gpu/drm/tinydrm/mipi-dbi.c | 24 ++++++++++++++++++++----
  include/drm/tinydrm/mipi-dbi.h     |  4 +++-
  2 files changed, 23 insertions(+), 5 deletions(-)

drivers/gpu/drm/tinydrm/mipi-dbi.c +20 -4

index 347f9b2..aa6b6ce 100644
@@ -154,8 +154,18 @@ int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len)
  }
  EXPORT_SYMBOL(mipi_dbi_command_buf);
 
-static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
-				struct drm_clip_rect *clip, bool swap)
+/**
+ * mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
+ * @dst: The destination buffer
+ * @fb: The source framebuffer
+ * @clip: Clipping rectangle of the area to be copied
+ * @swap: When true, swap MSB/LSB of 16-bit values
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
+		      struct drm_clip_rect *clip, bool swap)
  {
  	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
  	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;

@@ -192,6 +202,7 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
  					     DMA_FROM_DEVICE);
  	return ret;
  }
+EXPORT_SYMBOL(mipi_dbi_buf_copy);
 
  static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
  			     struct drm_file *file_priv,

@@ -444,18 +455,23 @@ EXPORT_SYMBOL(mipi_dbi_display_is_on);
 
  #if IS_ENABLED(CONFIG_SPI)
 
-/*
+/**
+ * mipi_dbi_spi_cmd_max_speed - get the maximum SPI bus speed
+ * @spi: SPI device
+ * @len: The transfer buffer length.
+ *
   * Many controllers have a max speed of 10MHz, but can be pushed way beyond
   * that. Increase reliability by running pixel data at max speed and the rest
   * at 10MHz, preventing transfer glitches from messing up the init settings.
   */
-static u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len)
+u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len)
  {
  	if (len > 64)
  		return 0; /* use default */
 
  	return min_t(u32, 10000000, spi->max_speed_hz);
  }
+EXPORT_SYMBOL(mipi_dbi_spi_cmd_max_speed);
 
  /*
   * MIPI DBI Type C Option 1

include/drm/tinydrm/mipi-dbi.h +0 -0

index 83346dd..5d0e82b 100644
@@ -72,10 +72,12 @@ void mipi_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
  void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe);
  void mipi_dbi_hw_reset(struct mipi_dbi *mipi);
  bool mipi_dbi_display_is_on(struct mipi_dbi *mipi);

This adds a new driver for display panels based on the Ilitek ILI9225 controller.

This was developed for a no-name panel with a red PCB that is commonly marketed for Arduino. See <https://github.com/Nkawu/TFT_22_ILI9225>.

Signed-off-by David Lechner <[email protected]>

---

v2 changes:
* use exported mipi_dbi_* functions from patch 3/4
* new ili9225_command function

  MAINTAINERS                       |   6 +
  drivers/gpu/drm/tinydrm/Kconfig   |  10 +
  drivers/gpu/drm/tinydrm/Makefile  |   1 +
  drivers/gpu/drm/tinydrm/ili9225.c | 468 ++++++++++++++++++++++++++++++++++++++
  4 files changed, 485 insertions(+)

create mode 100644 drivers/gpu/drm/tinydrm/ili9225.c

MAINTAINERS +6 -0

index 0d77f22..72404f3 100644
@@ -4372,6 +4372,12 @@ T:	git git://anongit.freedesktop.org/drm/drm-misc
  S:	Maintained
  F:	drivers/gpu/drm/tve200/
 
+DRM DRIVER FOR ILITEK ILI9225 PANELS
+M:	David Lechner <[email protected]>
+S:	Maintained
+F:	drivers/gpu/drm/tinydrm/ili9225.c
+F:	Documentation/devicetree/bindings/display/ili9225.txt
+
  DRM DRIVER FOR INTEL I810 VIDEO CARDS
  S:	Orphan / Obsolete
  F:	drivers/gpu/drm/i810/

drivers/gpu/drm/tinydrm/Kconfig +10 -0

index 2e790e7..90c5bd5 100644
@@ -12,6 +12,16 @@ menuconfig DRM_TINYDRM
  config TINYDRM_MIPI_DBI
  	tristate
 
+config TINYDRM_ILI9225
+	tristate "DRM support for ILI9225 display panels"
+	depends on DRM_TINYDRM && SPI
+	select TINYDRM_MIPI_DBI
+	help
+	  DRM driver for the following Ilitek ILI9225 panels:
+	  * No-name 2.2" color screen module
+
+	  If M is selected the module will be called ili9225.
+
  config TINYDRM_MI0283QT
  	tristate "DRM support for MI0283QT"
  	depends on DRM_TINYDRM && SPI

drivers/gpu/drm/tinydrm/Makefile +1 -0

index 0c184bd..8aeee53 100644
@@ -4,6 +4,7 @@ obj-$(CONFIG_DRM_TINYDRM)		+= core/
  obj-$(CONFIG_TINYDRM_MIPI_DBI)		+= mipi-dbi.o
 
  # Displays
+obj-$(CONFIG_TINYDRM_ILI9225)		+= ili9225.o
  obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o
  obj-$(CONFIG_TINYDRM_REPAPER)		+= repaper.o
  obj-$(CONFIG_TINYDRM_ST7586)		+= st7586.o

drivers/gpu/drm/tinydrm/ili9225.c new file +458 -0

new file mode 100644
index 0000000..3b766a2
@@ -0,0 +1,468 @@
+/*
+ * DRM driver for Ilitek ILI9225 panels
+ *
+ * Copyright 2017 David Lechner <[email protected]>
+ *
+ * Some code copied from mipi-dbi.c
+ * Copyright 2016 Noralf Trønnes
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#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/drm_gem_framebuffer_helper.h>
+#include <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+
+#define ILI9225_DRIVER_READ_CODE	0x00
+#define ILI9225_DRIVER_OUTPUT_CONTROL	0x01
+#define ILI9225_LCD_AC_DRIVING_CONTROL	0x02
+#define ILI9225_ENTRY_MODE		0x03
+#define ILI9225_DISPLAY_CONTROL_1	0x07
+#define ILI9225_BLANK_PERIOD_CONTROL_1	0x08
+#define ILI9225_FRAME_CYCLE_CONTROL	0x0b
+#define ILI9225_INTERFACE_CONTROL	0x0c
+#define ILI9225_OSCILLATION_CONTROL	0x0f
+#define ILI9225_POWER_CONTROL_1		0x10
+#define ILI9225_POWER_CONTROL_2		0x11
+#define ILI9225_POWER_CONTROL_3		0x12
+#define ILI9225_POWER_CONTROL_4		0x13
+#define ILI9225_POWER_CONTROL_5		0x14
+#define ILI9225_VCI_RECYCLING		0x15
+#define ILI9225_RAM_ADDRESS_SET_1	0x20
+#define ILI9225_RAM_ADDRESS_SET_2	0x21
+#define ILI9225_WRITE_DATA_TO_GRAM	0x22
+#define ILI9225_SOFTWARE_RESET		0x28
+#define ILI9225_GATE_SCAN_CONTROL	0x30
+#define ILI9225_VERTICAL_SCROLL_1	0x31
+#define ILI9225_VERTICAL_SCROLL_2	0x32
+#define ILI9225_VERTICAL_SCROLL_3	0x33
+#define ILI9225_PARTIAL_DRIVING_POS_1	0x34
+#define ILI9225_PARTIAL_DRIVING_POS_2	0x35
+#define ILI9225_HORIZ_WINDOW_ADDR_1	0x36
+#define ILI9225_HORIZ_WINDOW_ADDR_2	0x37
+#define ILI9225_VERT_WINDOW_ADDR_1	0x38
+#define ILI9225_VERT_WINDOW_ADDR_2	0x39
+#define ILI9225_GAMMA_CONTROL_1		0x50
+#define ILI9225_GAMMA_CONTROL_2		0x51
+#define ILI9225_GAMMA_CONTROL_3		0x52
+#define ILI9225_GAMMA_CONTROL_4		0x53
+#define ILI9225_GAMMA_CONTROL_5		0x54
+#define ILI9225_GAMMA_CONTROL_6		0x55
+#define ILI9225_GAMMA_CONTROL_7		0x56
+#define ILI9225_GAMMA_CONTROL_8		0x57
+#define ILI9225_GAMMA_CONTROL_9		0x58
+#define ILI9225_GAMMA_CONTROL_10	0x59
+
+static inline int ili9225_command(struct mipi_dbi *mipi, u8 cmd, u16 data)
+{
+	u8 par[2] = { data >> 8, data & 0xff };
+
+	return mipi_dbi_command_buf(mipi, cmd, par, 2);
+}
+
+static int ili9225_fb_dirty(struct drm_framebuffer *fb,
+			    struct drm_file *file_priv, unsigned int flags,
+			    unsigned int color, struct drm_clip_rect *clips,
+			    unsigned int num_clips)
+{
+	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+	struct tinydrm_device *tdev = fb->dev->dev_private;
+	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+	bool swap = mipi->swap_bytes;
+	struct drm_clip_rect clip;
+	u16 x_start, y_start;
+	u16 x1, x2, y1, y2;
+	int ret = 0;
+	bool full;
+	void *tr;
+
+	mutex_lock(&tdev->dirty_lock);
+
+	if (!mipi->enabled)
+		goto out_unlock;
+
+	/* fbdev can flush even when we're not interested */
+	if (tdev->pipe.plane.fb != fb)
+		goto out_unlock;
+
+	full = tinydrm_merge_clips(&clip, clips, num_clips, flags,
+				   fb->width, fb->height);
+
+	DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", fb->base.id,
+		  clip.x1, clip.x2, clip.y1, clip.y2);
+
+	if (!mipi->dc || !full || swap ||
+	    fb->format->format == DRM_FORMAT_XRGB8888) {
+		tr = mipi->tx_buf;
+		ret = mipi_dbi_buf_copy(mipi->tx_buf, fb, &clip, swap);
+		if (ret)
+			goto out_unlock;
+	} else {
+		tr = cma_obj->vaddr;
+	}
+
+	switch (mipi->rotation) {
+	default:
+		x1 = clip.x1;
+		x2 = clip.x2 - 1;
+		y1 = clip.y1;
+		y2 = clip.y2 - 1;
+		x_start = x1;
+		y_start = y1;
+		break;
+	case 90:
+		x1 = clip.y1;
+		x2 = clip.y2 - 1;
+		y1 = fb->width - clip.x2;
+		y2 = fb->width - clip.x1 - 1;
+		x_start = x1;
+		y_start = y2;
+		break;
+	case 180:
+		x1 = fb->width - clip.x2;
+		x2 = fb->width - clip.x1 - 1;
+		y1 = fb->height - clip.y2;
+		y2 = fb->height - clip.y1 - 1;
+		x_start = x2;
+		y_start = y2;
+		break;
+	case 270:
+		x1 = fb->height - clip.y2;
+		x2 = fb->height - clip.y1 - 1;
+		y1 = clip.x1;
+		y2 = clip.x2 - 1;
+		x_start = x2;
+		y_start = y1;
+		break;
+	}
+
+	ili9225_command(mipi, ILI9225_HORIZ_WINDOW_ADDR_1, x2);
+	ili9225_command(mipi, ILI9225_HORIZ_WINDOW_ADDR_2, x1);
+	ili9225_command(mipi, ILI9225_VERT_WINDOW_ADDR_1, y2);
+	ili9225_command(mipi, ILI9225_VERT_WINDOW_ADDR_2, y1);
+
+	ili9225_command(mipi, ILI9225_RAM_ADDRESS_SET_1, x_start);
+	ili9225_command(mipi, ILI9225_RAM_ADDRESS_SET_2, y_start);
+
+	ret = mipi_dbi_command_buf(mipi, ILI9225_WRITE_DATA_TO_GRAM, tr,
+				(clip.x2 - clip.x1) * (clip.y2 - clip.y1) * 2);
+
+out_unlock:
+	mutex_unlock(&tdev->dirty_lock);
+
+	if (ret)
+		dev_err_once(fb->dev->dev, "Failed to update display %d\n",
+			     ret);
+
+	return ret;
+}
+
+static const struct drm_framebuffer_funcs ili9225_fb_funcs = {
+	.destroy	= drm_gem_fb_destroy,
+	.create_handle	= drm_gem_fb_create_handle,
+	.dirty		= ili9225_fb_dirty,
+};
+
+static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
+				struct drm_crtc_state *crtc_state)
+{
+	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+	struct drm_framebuffer *fb = pipe->plane.fb;
+	struct device *dev = tdev->drm->dev;
+	int ret;
+	u8 am_id;
+
+	DRM_DEBUG_KMS("\n");
+
+	mipi_dbi_hw_reset(mipi);
+
+	/*
+	 * There don't seem to be two example init sequences that match, so
+	 * using the one from the popular Arduino library for this display.
+	 * https://github.com/Nkawu/TFT_22_ILI9225/blob/master/src/TFT_22_ILI9225.cpp
+	 */
+
+	ret = ili9225_command(mipi, ILI9225_POWER_CONTROL_1, 0x0000);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
+		return;
+	}
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_2, 0x0000);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_3, 0x0000);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_4, 0x0000);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_5, 0x0000);
+
+	msleep(40);
+
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_2, 0x0018);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_3, 0x6121);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_4, 0x006f);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_5, 0x495f);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_1, 0x0800);
+
+	msleep(10);
+
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_2, 0x103b);
+
+	msleep(50);
+
+	switch (mipi->rotation) {
+	default:
+		am_id = 0x30;
+		break;
+	case 90:
+		am_id = 0x18;
+		break;
+	case 180:
+		am_id = 0x00;
+		break;
+	case 270:
+		am_id = 0x28;
+		break;
+	}
+	ili9225_command(mipi, ILI9225_DRIVER_OUTPUT_CONTROL, 0x011c);
+	ili9225_command(mipi, ILI9225_LCD_AC_DRIVING_CONTROL, 0x0100);
+	ili9225_command(mipi, ILI9225_ENTRY_MODE, 0x1000 | am_id);
+	ili9225_command(mipi, ILI9225_DISPLAY_CONTROL_1, 0x0000);
+	ili9225_command(mipi, ILI9225_BLANK_PERIOD_CONTROL_1, 0x0808);
+	ili9225_command(mipi, ILI9225_FRAME_CYCLE_CONTROL, 0x1100);
+	ili9225_command(mipi, ILI9225_INTERFACE_CONTROL, 0x0000);
+	ili9225_command(mipi, ILI9225_OSCILLATION_CONTROL, 0x0d01);
+	ili9225_command(mipi, ILI9225_VCI_RECYCLING, 0x0020);
+	ili9225_command(mipi, ILI9225_RAM_ADDRESS_SET_1, 0x0000);
+	ili9225_command(mipi, ILI9225_RAM_ADDRESS_SET_2, 0x0000);
+
+	ili9225_command(mipi, ILI9225_GATE_SCAN_CONTROL, 0x0000);
+	ili9225_command(mipi, ILI9225_VERTICAL_SCROLL_1, 0x00db);
+	ili9225_command(mipi, ILI9225_VERTICAL_SCROLL_2, 0x0000);
+	ili9225_command(mipi, ILI9225_VERTICAL_SCROLL_3, 0x0000);
+	ili9225_command(mipi, ILI9225_PARTIAL_DRIVING_POS_1, 0x00db);
+	ili9225_command(mipi, ILI9225_PARTIAL_DRIVING_POS_2, 0x0000);
+
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_1, 0x0000);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_2, 0x0808);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_3, 0x080a);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_4, 0x000a);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_5, 0x0a08);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_6, 0x0808);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_7, 0x0000);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_8, 0x0a00);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_9, 0x0710);
+	ili9225_command(mipi, ILI9225_GAMMA_CONTROL_10, 0x0710);
+
+	ili9225_command(mipi, ILI9225_DISPLAY_CONTROL_1, 0x0012);
+
+	msleep(50);
+
+	ili9225_command(mipi, ILI9225_DISPLAY_CONTROL_1, 0x1017);
+
+	mipi->enabled = true;
+
+	if (fb)
+		fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
+}
+
+static void ili9225_pipe_disable(struct drm_simple_display_pipe *pipe)
+{
+	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+
+	DRM_DEBUG_KMS("\n");
+
+	if (!mipi->enabled)
+		return;
+
+	ili9225_command(mipi, ILI9225_DISPLAY_CONTROL_1, 0x0000);
+	msleep(50);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_2, 0x0007);
+	msleep(50);
+	ili9225_command(mipi, ILI9225_POWER_CONTROL_1, 0x0a02);
+
+	mipi->enabled = false;
+}
+
+static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 cmd, u8 *par,
+			       size_t num)
+{
+	struct spi_device *spi = mipi->spi;
+	unsigned int bpw = 8;
+	u32 speed_hz;
+	int ret;
+
+	gpiod_set_value_cansleep(mipi->dc, 0);
+	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
+	ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, &cmd, 1);
+	if (ret || !num)
+		return ret;
+
+	if (cmd == ILI9225_WRITE_DATA_TO_GRAM && !mipi->swap_bytes)
+		bpw = 16;
+
+	gpiod_set_value_cansleep(mipi->dc, 1);
+	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);
+
+	return tinydrm_spi_transfer(spi, speed_hz, NULL, bpw, par, num);
+}
+
+static const u32 ili9225_formats[] = {
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_XRGB8888,
+};
+
+static int ili9225_init(struct device *dev, struct mipi_dbi *mipi,
+			const struct drm_simple_display_pipe_funcs *pipe_funcs,
+			struct drm_driver *driver,
+			const struct drm_display_mode *mode,
+			unsigned int rotation)
+{
+	size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
+	struct tinydrm_device *tdev = &mipi->tinydrm;
+	int ret;
+
+	if (!mipi->command)
+		return -EINVAL;
+
+	mutex_init(&mipi->cmdlock);
+
+	mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
+	if (!mipi->tx_buf)
+		return -ENOMEM;
+
+	ret = devm_tinydrm_init(dev, tdev, &ili9225_fb_funcs, driver);
+	if (ret)
+		return ret;
+
+	ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
+					DRM_MODE_CONNECTOR_VIRTUAL,
+					ili9225_formats,
+					ARRAY_SIZE(ili9225_formats), mode,
+					rotation);
+	if (ret)
+		return ret;
+
+	tdev->drm->mode_config.preferred_depth = 16;
+	mipi->rotation = rotation;
+
+	drm_mode_config_reset(tdev->drm);
+
+	DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
+		      tdev->drm->mode_config.preferred_depth, rotation);
+
+	return 0;
+}
+
+static const struct drm_simple_display_pipe_funcs ili9225_pipe_funcs = {
+	.enable		= ili9225_pipe_enable,
+	.disable	= ili9225_pipe_disable,
+	.update		= tinydrm_display_pipe_update,
+	.prepare_fb	= tinydrm_display_pipe_prepare_fb,
+};
+
+static const struct drm_display_mode ili9225_mode = {
+	TINYDRM_MODE(176, 220, 35, 44),
+};
+
+DEFINE_DRM_GEM_CMA_FOPS(ili9225_fops);
+
+static struct drm_driver ili9225_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
+				  DRIVER_ATOMIC,
+	.fops			= &ili9225_fops,
+	TINYDRM_GEM_DRIVER_OPS,
+	.lastclose		= tinydrm_lastclose,
+	.name			= "ili9225",
+	.desc			= "Ilitek ILI9225",
+	.date			= "20171106",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id ili9225_of_match[] = {
+	{ .compatible = "ilitek,ili9225-2.2in-176x220" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ili9225_of_match);
+
+static const struct spi_device_id ili9225_id[] = {
+	{ "ili9225-2.2in-176x220", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, ili9225_id);
+
+static int ili9225_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct mipi_dbi *mipi;
+	struct gpio_desc *rs;
+	u32 rotation = 0;
+	int ret;
+
+	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
+	if (!mipi)
+		return -ENOMEM;
+
+	mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(mipi->reset)) {
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
+		return PTR_ERR(mipi->reset);
+	}
+
+	rs = devm_gpiod_get(dev, "rs", GPIOD_OUT_LOW);
+	if (IS_ERR(rs)) {
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'rs'\n");
+		return PTR_ERR(rs);
+	}
+
+	device_property_read_u32(dev, "rotation", &rotation);
+
+	ret = mipi_dbi_spi_init(spi, mipi, rs);
+	if (ret)
+		return ret;
+
+	/* override the command function set in  mipi_dbi_spi_init() */
+	mipi->command = ili9225_dbi_command;
+
+	ret = ili9225_init(&spi->dev, mipi, &ili9225_pipe_funcs,
+			   &ili9225_driver, &ili9225_mode, rotation);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, mipi);
+
+	return devm_tinydrm_register(&mipi->tinydrm);
+}
+
+static void ili9225_shutdown(struct spi_device *spi)
+{
+	struct mipi_dbi *mipi = spi_get_drvdata(spi);
+
+	tinydrm_shutdown(&mipi->tinydrm);
+}
+
+static struct spi_driver ili9225_spi_driver = {
+	.driver = {
+		.name = "ili9225",
+		.owner = THIS_MODULE,
+		.of_match_table = ili9225_of_match,

This is a new driver for ILI9225 based display panels.

v2 changes:
* New patch for ilitek vendor prefix.
* Use "ilitek" instead of "generic" in dt-bindings
* New patch to export 2 mipi_dbi_* functions
* Clean up ILI9225 driver based on feedback

David Lechner (4):
dt-bindings: Add vendor prefix for ilitek
dt-bindings: Add binding for Ilitek ILI9225 display panels drm/tinydrm: export mipi_dbi_buf_copy and mipi_dbi_spi_cmd_max_speed drm/tinydrm: add driver for ILI9225 panels

  .../devicetree/bindings/display/ilitek,ili9225.txt |  25 ++
  .../devicetree/bindings/vendor-prefixes.txt        |   1 +
  MAINTAINERS                                        |   6 +
  drivers/gpu/drm/tinydrm/Kconfig                    |  10 +
  drivers/gpu/drm/tinydrm/Makefile                   |   1 +
  drivers/gpu/drm/tinydrm/ili9225.c                  | 468 +++++++++++++++++++++
  drivers/gpu/drm/tinydrm/mipi-dbi.c                 |  24 +-
  include/drm/tinydrm/mipi-dbi.h                     |   4 +-
  8 files changed, 534 insertions(+), 5 deletions(-)

create mode 100644 Documentation/devicetree/bindings/display/ilitek,ili9225.txt create mode 100644 drivers/gpu/drm/tinydrm/ili9225.c