Merge tag 'drm-tinydrm-2017-02-18' of https://github.com/notro/linux into drm-next

Add tinydrm

* tag 'drm-tinydrm-2017-02-18' of https://github.com/notro/linux:
  drm/tinydrm: Add support for Multi-Inno MI0283QT display
  dt-bindings: Add Multi-Inno MI0283QT binding
  dt-bindings: display/panel: Add common rotation property
  of: Add vendor prefix for Multi-Inno
  drm/tinydrm: Add MIPI DBI support
  drm/tinydrm: Add helper functions
  drm: Add DRM support for tiny LCD displays

10 files changed, 2388 insertions, 0 deletions

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 90bc65d07a35..88e01e08e279 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -263,6 +263,8 @@ source "drivers/gpu/drm/mxsfb/Kconfig"
 
 source "drivers/gpu/drm/meson/Kconfig"
 
+source "drivers/gpu/drm/tinydrm/Kconfig"
+
 # Keep legacy drivers last
 
 menuconfig DRM_LEGACY
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 92de3991fa56..3ee95793d122 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -94,3 +94,4 @@ obj-$(CONFIG_DRM_ARCPGU)+= arc/
 obj-y			+= hisilicon/
 obj-$(CONFIG_DRM_ZTE)	+= zte/
 obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
+obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig
new file mode 100644
index 000000000000..3504c53846da
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/Kconfig
@@ -0,0 +1,21 @@
+menuconfig DRM_TINYDRM
+	tristate "Support for simple displays"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_CMA_HELPER
+	select BACKLIGHT_LCD_SUPPORT
+	select BACKLIGHT_CLASS_DEVICE
+	help
+	  Choose this option if you have a tinydrm supported display.
+	  If M is selected the module will be called tinydrm.
+
+config TINYDRM_MIPI_DBI
+	tristate
+
+config TINYDRM_MI0283QT
+	tristate "DRM support for MI0283QT"
+	depends on DRM_TINYDRM && SPI
+	select TINYDRM_MIPI_DBI
+	help
+	  DRM driver for the Multi-Inno MI0283QT display panel
+	  If M is selected the module will be called mi0283qt.
diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile
new file mode 100644
index 000000000000..7a3604cf4fc2
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/Makefile
@@ -0,0 +1,7 @@
+obj-$(CONFIG_DRM_TINYDRM)		+= core/
+
+# Controllers
+obj-$(CONFIG_TINYDRM_MIPI_DBI)		+= mipi-dbi.o
+
+# Displays
+obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o
diff --git a/drivers/gpu/drm/tinydrm/core/Makefile b/drivers/gpu/drm/tinydrm/core/Makefile
new file mode 100644
index 000000000000..fb221e6f8885
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/core/Makefile
@@ -0,0 +1,3 @@
+tinydrm-y := tinydrm-core.o tinydrm-pipe.o tinydrm-helpers.o
+
+obj-$(CONFIG_DRM_TINYDRM) += tinydrm.o
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-core.c b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
new file mode 100644
index 000000000000..6a257dd08ee0
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
@@ -0,0 +1,376 @@
+/*
+ * Copyright (C) 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 <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/tinydrm/tinydrm.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+
+/**
+ * DOC: overview
+ *
+ * This library provides driver helpers for very simple display hardware.
+ *
+ * It is based on &drm_simple_display_pipe coupled with a &drm_connector which
+ * has only one fixed &drm_display_mode. The framebuffers are backed by the
+ * cma helper and have support for framebuffer flushing (dirty).
+ * fbdev support is also included.
+ *
+ */
+
+/**
+ * DOC: core
+ *
+ * The driver allocates &tinydrm_device, initializes it using
+ * devm_tinydrm_init(), sets up the pipeline using tinydrm_display_pipe_init()
+ * and registers the DRM device using devm_tinydrm_register().
+ */
+
+/**
+ * tinydrm_lastclose - DRM lastclose helper
+ * @drm: DRM device
+ *
+ * This function ensures that fbdev is restored when drm_lastclose() is called
+ * on the last drm_release(). Drivers can use this as their
+ * &drm_driver->lastclose callback.
+ */
+void tinydrm_lastclose(struct drm_device *drm)
+{
+	struct tinydrm_device *tdev = drm->dev_private;
+
+	DRM_DEBUG_KMS("\n");
+	drm_fbdev_cma_restore_mode(tdev->fbdev_cma);
+}
+EXPORT_SYMBOL(tinydrm_lastclose);
+
+/**
+ * tinydrm_gem_cma_prime_import_sg_table - Produce a CMA GEM object from
+ *     another driver's scatter/gather table of pinned pages
+ * @drm: DRM device to import into
+ * @attach: DMA-BUF attachment
+ * @sgt: Scatter/gather table of pinned pages
+ *
+ * This function imports a scatter/gather table exported via DMA-BUF by
+ * another driver using drm_gem_cma_prime_import_sg_table(). It sets the
+ * kernel virtual address on the CMA object. Drivers should use this as their
+ * &drm_driver->gem_prime_import_sg_table callback if they need the virtual
+ * address. tinydrm_gem_cma_free_object() should be used in combination with
+ * this function.
+ *
+ * Returns:
+ * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
+ * error code on failure.
+ */
+struct drm_gem_object *
+tinydrm_gem_cma_prime_import_sg_table(struct drm_device *drm,
+				      struct dma_buf_attachment *attach,
+				      struct sg_table *sgt)
+{
+	struct drm_gem_cma_object *cma_obj;
+	struct drm_gem_object *obj;
+	void *vaddr;
+
+	vaddr = dma_buf_vmap(attach->dmabuf);
+	if (!vaddr) {
+		DRM_ERROR("Failed to vmap PRIME buffer\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	obj = drm_gem_cma_prime_import_sg_table(drm, attach, sgt);
+	if (IS_ERR(obj)) {
+		dma_buf_vunmap(attach->dmabuf, vaddr);
+		return obj;
+	}
+
+	cma_obj = to_drm_gem_cma_obj(obj);
+	cma_obj->vaddr = vaddr;
+
+	return obj;
+}
+EXPORT_SYMBOL(tinydrm_gem_cma_prime_import_sg_table);
+
+/**
+ * tinydrm_gem_cma_free_object - Free resources associated with a CMA GEM
+ *                               object
+ * @gem_obj: GEM object to free
+ *
+ * This function frees the backing memory of the CMA GEM object, cleans up the
+ * GEM object state and frees the memory used to store the object itself using
+ * drm_gem_cma_free_object(). It also handles PRIME buffers which has the kernel
+ * virtual address set by tinydrm_gem_cma_prime_import_sg_table(). Drivers
+ * can use this as their &drm_driver->gem_free_object callback.
+ */
+void tinydrm_gem_cma_free_object(struct drm_gem_object *gem_obj)
+{
+	if (gem_obj->import_attach) {
+		struct drm_gem_cma_object *cma_obj;
+
+		cma_obj = to_drm_gem_cma_obj(gem_obj);
+		dma_buf_vunmap(gem_obj->import_attach->dmabuf, cma_obj->vaddr);
+		cma_obj->vaddr = NULL;
+	}
+
+	drm_gem_cma_free_object(gem_obj);
+}
+EXPORT_SYMBOL_GPL(tinydrm_gem_cma_free_object);
+
+const struct file_operations tinydrm_fops = {
+	.owner		= THIS_MODULE,
+	.open		= drm_open,
+	.release	= drm_release,
+	.unlocked_ioctl	= drm_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= drm_compat_ioctl,
+#endif
+	.poll		= drm_poll,
+	.read		= drm_read,
+	.llseek		= no_llseek,
+	.mmap		= drm_gem_cma_mmap,
+};
+EXPORT_SYMBOL(tinydrm_fops);
+
+static struct drm_framebuffer *
+tinydrm_fb_create(struct drm_device *drm, struct drm_file *file_priv,
+		  const struct drm_mode_fb_cmd2 *mode_cmd)
+{
+	struct tinydrm_device *tdev = drm->dev_private;
+
+	return drm_fb_cma_create_with_funcs(drm, file_priv, mode_cmd,
+					    tdev->fb_funcs);
+}
+
+static const struct drm_mode_config_funcs tinydrm_mode_config_funcs = {
+	.fb_create = tinydrm_fb_create,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static int tinydrm_init(struct device *parent, struct tinydrm_device *tdev,
+			const struct drm_framebuffer_funcs *fb_funcs,
+			struct drm_driver *driver)
+{
+	struct drm_device *drm;
+
+	mutex_init(&tdev->dirty_lock);
+	tdev->fb_funcs = fb_funcs;
+
+	/*
+	 * We don't embed drm_device, because that prevent us from using
+	 * devm_kzalloc() to allocate tinydrm_device in the driver since
+	 * drm_dev_unref() frees the structure. The devm_ functions provide
+	 * for easy error handling.
+	 */
+	drm = drm_dev_alloc(driver, parent);
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
+
+	tdev->drm = drm;
+	drm->dev_private = tdev;
+	drm_mode_config_init(drm);
+	drm->mode_config.funcs = &tinydrm_mode_config_funcs;
+
+	return 0;
+}
+
+static void tinydrm_fini(struct tinydrm_device *tdev)
+{
+	drm_mode_config_cleanup(tdev->drm);
+	mutex_destroy(&tdev->dirty_lock);
+	tdev->drm->dev_private = NULL;
+	drm_dev_unref(tdev->drm);
+}
+
+static void devm_tinydrm_release(void *data)
+{
+	tinydrm_fini(data);
+}
+
+/**
+ * devm_tinydrm_init - Initialize tinydrm device
+ * @parent: Parent device object
+ * @tdev: tinydrm device
+ * @fb_funcs: Framebuffer functions
+ * @driver: DRM driver
+ *
+ * This function initializes @tdev, the underlying DRM device and it's
+ * mode_config. Resources will be automatically freed on driver detach (devres)
+ * using drm_mode_config_cleanup() and drm_dev_unref().
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int devm_tinydrm_init(struct device *parent, struct tinydrm_device *tdev,
+		      const struct drm_framebuffer_funcs *fb_funcs,
+		      struct drm_driver *driver)
+{
+	int ret;
+
+	ret = tinydrm_init(parent, tdev, fb_funcs, driver);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action(parent, devm_tinydrm_release, tdev);
+	if (ret)
+		tinydrm_fini(tdev);
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_tinydrm_init);
+
+static int tinydrm_register(struct tinydrm_device *tdev)
+{
+	struct drm_device *drm = tdev->drm;
+	int bpp = drm->mode_config.preferred_depth;
+	struct drm_fbdev_cma *fbdev;
+	int ret;
+
+	ret = drm_dev_register(tdev->drm, 0);
+	if (ret)
+		return ret;
+
+	fbdev = drm_fbdev_cma_init_with_funcs(drm, bpp ? bpp : 32,
+					      drm->mode_config.num_connector,
+					      tdev->fb_funcs);
+	if (IS_ERR(fbdev))
+		DRM_ERROR("Failed to initialize fbdev: %ld\n", PTR_ERR(fbdev));
+	else
+		tdev->fbdev_cma = fbdev;
+
+	return 0;
+}
+
+static void tinydrm_unregister(struct tinydrm_device *tdev)
+{
+	struct drm_fbdev_cma *fbdev_cma = tdev->fbdev_cma;
+
+	drm_crtc_force_disable_all(tdev->drm);
+	/* don't restore fbdev in lastclose, keep pipeline disabled */
+	tdev->fbdev_cma = NULL;
+	drm_dev_unregister(tdev->drm);
+	if (fbdev_cma)
+		drm_fbdev_cma_fini(fbdev_cma);
+}
+
+static void devm_tinydrm_register_release(void *data)
+{
+	tinydrm_unregister(data);
+}
+
+/**
+ * devm_tinydrm_register - Register tinydrm device
+ * @tdev: tinydrm device
+ *
+ * This function registers the underlying DRM device and fbdev.
+ * These resources will be automatically unregistered on driver detach (devres)
+ * and the display pipeline will be disabled.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int devm_tinydrm_register(struct tinydrm_device *tdev)
+{
+	struct device *dev = tdev->drm->dev;
+	int ret;
+
+	ret = tinydrm_register(tdev);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action(dev, devm_tinydrm_register_release, tdev);
+	if (ret)
+		tinydrm_unregister(tdev);
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_tinydrm_register);
+
+/**
+ * tinydrm_shutdown - Shutdown tinydrm
+ * @tdev: tinydrm device
+ *
+ * This function makes sure that the display pipeline is disabled.
+ * Used by drivers in their shutdown callback to turn off the display
+ * on machine shutdown and reboot.
+ */
+void tinydrm_shutdown(struct tinydrm_device *tdev)
+{
+	drm_crtc_force_disable_all(tdev->drm);
+}
+EXPORT_SYMBOL(tinydrm_shutdown);
+
+/**
+ * tinydrm_suspend - Suspend tinydrm
+ * @tdev: tinydrm device
+ *
+ * Used in driver PM operations to suspend tinydrm.
+ * Suspends fbdev and DRM.
+ * Resume with tinydrm_resume().
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int tinydrm_suspend(struct tinydrm_device *tdev)
+{
+	struct drm_atomic_state *state;
+
+	if (tdev->suspend_state) {
+		DRM_ERROR("Failed to suspend: state already set\n");
+		return -EINVAL;
+	}
+
+	drm_fbdev_cma_set_suspend_unlocked(tdev->fbdev_cma, 1);
+	state = drm_atomic_helper_suspend(tdev->drm);
+	if (IS_ERR(state)) {
+		drm_fbdev_cma_set_suspend_unlocked(tdev->fbdev_cma, 0);
+		return PTR_ERR(state);
+	}
+
+	tdev->suspend_state = state;
+
+	return 0;
+}
+EXPORT_SYMBOL(tinydrm_suspend);
+
+/**
+ * tinydrm_resume - Resume tinydrm
+ * @tdev: tinydrm device
+ *
+ * Used in driver PM operations to resume tinydrm.
+ * Suspend with tinydrm_suspend().
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int tinydrm_resume(struct tinydrm_device *tdev)
+{
+	struct drm_atomic_state *state = tdev->suspend_state;
+	int ret;
+
+	if (!state) {
+		DRM_ERROR("Failed to resume: state is not set\n");
+		return -EINVAL;
+	}
+
+	tdev->suspend_state = NULL;
+
+	ret = drm_atomic_helper_resume(tdev->drm, state);
+	if (ret) {
+		DRM_ERROR("Error resuming state: %d\n", ret);
+		return ret;
+	}
+
+	drm_fbdev_cma_set_suspend_unlocked(tdev->fbdev_cma, 0);
+
+	return 0;
+}
+EXPORT_SYMBOL(tinydrm_resume);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
new file mode 100644
index 000000000000..3ccda6c1e159
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
@@ -0,0 +1,460 @@
+/*
+ * Copyright (C) 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 <drm/tinydrm/tinydrm.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+#include <linux/backlight.h>
+#include <linux/pm.h>
+#include <linux/spi/spi.h>
+#include <linux/swab.h>
+
+static unsigned int spi_max;
+module_param(spi_max, uint, 0400);
+MODULE_PARM_DESC(spi_max, "Set a lower SPI max transfer size");
+
+/**
+ * tinydrm_merge_clips - Merge clip rectangles
+ * @dst: Destination clip rectangle
+ * @src: Source clip rectangle(s)
+ * @num_clips: Number of @src clip rectangles
+ * @flags: Dirty fb ioctl flags
+ * @max_width: Maximum width of @dst
+ * @max_height: Maximum height of @dst
+ *
+ * This function merges @src clip rectangle(s) into @dst. If @src is NULL,
+ * @max_width and @min_width is used to set a full @dst clip rectangle.
+ *
+ * Returns:
+ * true if it's a full clip, false otherwise
+ */
+bool tinydrm_merge_clips(struct drm_clip_rect *dst,
+			 struct drm_clip_rect *src, unsigned int num_clips,
+			 unsigned int flags, u32 max_width, u32 max_height)
+{
+	unsigned int i;
+
+	if (!src || !num_clips) {
+		dst->x1 = 0;
+		dst->x2 = max_width;
+		dst->y1 = 0;
+		dst->y2 = max_height;
+		return true;
+	}
+
+	dst->x1 = ~0;
+	dst->y1 = ~0;
+	dst->x2 = 0;
+	dst->y2 = 0;
+
+	for (i = 0; i < num_clips; i++) {
+		if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY)
+			i++;
+		dst->x1 = min(dst->x1, src[i].x1);
+		dst->x2 = max(dst->x2, src[i].x2);
+		dst->y1 = min(dst->y1, src[i].y1);
+		dst->y2 = max(dst->y2, src[i].y2);
+	}
+
+	if (dst->x2 > max_width || dst->y2 > max_height ||
+	    dst->x1 >= dst->x2 || dst->y1 >= dst->y2) {
+		DRM_DEBUG_KMS("Illegal clip: x1=%u, x2=%u, y1=%u, y2=%u\n",
+			      dst->x1, dst->x2, dst->y1, dst->y2);
+		dst->x1 = 0;
+		dst->y1 = 0;
+		dst->x2 = max_width;
+		dst->y2 = max_height;
+	}
+
+	return (dst->x2 - dst->x1) == max_width &&
+	       (dst->y2 - dst->y1) == max_height;
+}
+EXPORT_SYMBOL(tinydrm_merge_clips);
+
+/**
+ * tinydrm_memcpy - Copy clip buffer
+ * @dst: Destination buffer
+ * @vaddr: Source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ */
+void tinydrm_memcpy(void *dst, void *vaddr, struct drm_framebuffer *fb,
+		    struct drm_clip_rect *clip)
+{
+	unsigned int cpp = drm_format_plane_cpp(fb->format->format, 0);
+	unsigned int pitch = fb->pitches[0];
+	void *src = vaddr + (clip->y1 * pitch) + (clip->x1 * cpp);
+	size_t len = (clip->x2 - clip->x1) * cpp;
+	unsigned int y;
+
+	for (y = clip->y1; y < clip->y2; y++) {
+		memcpy(dst, src, len);
+		src += pitch;
+		dst += len;
+	}
+}
+EXPORT_SYMBOL(tinydrm_memcpy);
+
+/**
+ * tinydrm_swab16 - Swap bytes into clip buffer
+ * @dst: RGB565 destination buffer
+ * @vaddr: RGB565 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ */
+void tinydrm_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
+		    struct drm_clip_rect *clip)
+{
+	size_t len = (clip->x2 - clip->x1) * sizeof(u16);
+	unsigned int x, y;
+	u16 *src, *buf;
+
+	/*
+	 * The cma memory is write-combined so reads are uncached.
+	 * Speed up by fetching one line at a time.
+	 */
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	for (y = clip->y1; y < clip->y2; y++) {
+		src = vaddr + (y * fb->pitches[0]);
+		src += clip->x1;
+		memcpy(buf, src, len);
+		src = buf;
+		for (x = clip->x1; x < clip->x2; x++)
+			*dst++ = swab16(*src++);
+	}
+
+	kfree(buf);
+}
+EXPORT_SYMBOL(tinydrm_swab16);
+
+/**
+ * tinydrm_xrgb8888_to_rgb565 - Convert XRGB8888 to RGB565 clip buffer
+ * @dst: RGB565 destination buffer
+ * @vaddr: XRGB8888 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ * @swap: Swap bytes
+ *
+ * Drivers can use this function for RGB565 devices that don't natively
+ * support XRGB8888.
+ */
+void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
+				struct drm_framebuffer *fb,
+				struct drm_clip_rect *clip, bool swap)
+{
+	size_t len = (clip->x2 - clip->x1) * sizeof(u32);
+	unsigned int x, y;
+	u32 *src, *buf;
+	u16 val16;
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	for (y = clip->y1; y < clip->y2; y++) {
+		src = vaddr + (y * fb->pitches[0]);
+		src += clip->x1;
+		memcpy(buf, src, len);
+		src = buf;
+		for (x = clip->x1; x < clip->x2; x++) {
+			val16 = ((*src & 0x00F80000) >> 8) |
+				((*src & 0x0000FC00) >> 5) |
+				((*src & 0x000000F8) >> 3);
+			src++;
+			if (swap)
+				*dst++ = swab16(val16);
+			else
+				*dst++ = val16;
+		}
+	}
+
+	kfree(buf);
+}
+EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
+
+/**
+ * tinydrm_of_find_backlight - Find backlight device in device-tree
+ * @dev: Device
+ *
+ * This function looks for a DT node pointed to by a property named 'backlight'
+ * and uses of_find_backlight_by_node() to get the backlight device.
+ * Additionally if the brightness property is zero, it is set to
+ * max_brightness.
+ *
+ * Returns:
+ * NULL if there's no backlight property.
+ * Error pointer -EPROBE_DEFER if the DT node is found, but no backlight device
+ * is found.
+ * If the backlight device is found, a pointer to the structure is returned.
+ */
+struct backlight_device *tinydrm_of_find_backlight(struct device *dev)
+{
+	struct backlight_device *backlight;
+	struct device_node *np;
+
+	np = of_parse_phandle(dev->of_node, "backlight", 0);
+	if (!np)
+		return NULL;
+
+	backlight = of_find_backlight_by_node(np);
+	of_node_put(np);
+
+	if (!backlight)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	if (!backlight->props.brightness) {
+		backlight->props.brightness = backlight->props.max_brightness;
+		DRM_DEBUG_KMS("Backlight brightness set to %d\n",
+			      backlight->props.brightness);
+	}
+
+	return backlight;
+}
+EXPORT_SYMBOL(tinydrm_of_find_backlight);
+
+/**
+ * tinydrm_enable_backlight - Enable backlight helper
+ * @backlight: Backlight device
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int tinydrm_enable_backlight(struct backlight_device *backlight)
+{
+	unsigned int old_state;
+	int ret;
+
+	if (!backlight)
+		return 0;
+
+	old_state = backlight->props.state;
+	backlight->props.state &= ~BL_CORE_FBBLANK;
+	DRM_DEBUG_KMS("Backlight state: 0x%x -> 0x%x\n", old_state,
+		      backlight->props.state);
+
+	ret = backlight_update_status(backlight);
+	if (ret)
+		DRM_ERROR("Failed to enable backlight %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL(tinydrm_enable_backlight);
+
+/**
+ * tinydrm_disable_backlight - Disable backlight helper
+ * @backlight: Backlight device
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int tinydrm_disable_backlight(struct backlight_device *backlight)
+{
+	unsigned int old_state;
+	int ret;
+
+	if (!backlight)
+		return 0;
+
+	old_state = backlight->props.state;
+	backlight->props.state |= BL_CORE_FBBLANK;
+	DRM_DEBUG_KMS("Backlight state: 0x%x -> 0x%x\n", old_state,
+		      backlight->props.state);
+	ret = backlight_update_status(backlight);
+	if (ret)
+		DRM_ERROR("Failed to disable backlight %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL(tinydrm_disable_backlight);
+
+#if IS_ENABLED(CONFIG_SPI)
+
+/**
+ * tinydrm_spi_max_transfer_size - Determine max SPI transfer size
+ * @spi: SPI device
+ * @max_len: Maximum buffer size needed (optional)
+ *
+ * This function returns the maximum size to use for SPI transfers. It checks
+ * the SPI master, the optional @max_len and the module parameter spi_max and
+ * returns the smallest.
+ *
+ * Returns:
+ * Maximum size for SPI transfers
+ */
+size_t tinydrm_spi_max_transfer_size(struct spi_device *spi, size_t max_len)
+{
+	size_t ret;
+
+	ret = min(spi_max_transfer_size(spi), spi->master->max_dma_len);
+	if (max_len)
+		ret = min(ret, max_len);
+	if (spi_max)
+		ret = min_t(size_t, ret, spi_max);
+	ret &= ~0x3;
+	if (ret < 4)
+		ret = 4;
+
+	return ret;
+}
+EXPORT_SYMBOL(tinydrm_spi_max_transfer_size);
+
+/**
+ * tinydrm_spi_bpw_supported - Check if bits per word is supported
+ * @spi: SPI device
+ * @bpw: Bits per word
+ *
+ * This function checks to see if the SPI master driver supports @bpw.
+ *
+ * Returns:
+ * True if @bpw is supported, false otherwise.
+ */
+bool tinydrm_spi_bpw_supported(struct spi_device *spi, u8 bpw)
+{
+	u32 bpw_mask = spi->master->bits_per_word_mask;
+
+	if (bpw == 8)
+		return true;
+
+	if (!bpw_mask) {
+		dev_warn_once(&spi->dev,
+			      "bits_per_word_mask not set, assume 8-bit only\n");
+		return false;
+	}
+
+	if (bpw_mask & SPI_BPW_MASK(bpw))
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(tinydrm_spi_bpw_supported);
+
+static void
+tinydrm_dbg_spi_print(struct spi_device *spi, struct spi_transfer *tr,
+		      const void *buf, int idx, bool tx)
+{
+	u32 speed_hz = tr->speed_hz ? tr->speed_hz : spi->max_speed_hz;
+	char linebuf[3 * 32];
+
+	hex_dump_to_buffer(buf, tr->len, 16,
+			   DIV_ROUND_UP(tr->bits_per_word, 8),
+			   linebuf, sizeof(linebuf), false);
+
+	printk(KERN_DEBUG
+	       "    tr(%i): speed=%u%s, bpw=%i, len=%u, %s_buf=[%s%s]\n", idx,
+	       speed_hz > 1000000 ? speed_hz / 1000000 : speed_hz / 1000,
+	       speed_hz > 1000000 ? "MHz" : "kHz", tr->bits_per_word, tr->len,
+	       tx ? "tx" : "rx", linebuf, tr->len > 16 ? " ..." : "");
+}
+
+/* called through tinydrm_dbg_spi_message() */
+void _tinydrm_dbg_spi_message(struct spi_device *spi, struct spi_message *m)
+{
+	struct spi_transfer *tmp;
+	struct list_head *pos;
+	int i = 0;
+
+	list_for_each(pos, &m->transfers) {
+		tmp = list_entry(pos, struct spi_transfer, transfer_list);
+
+		if (tmp->tx_buf)
+			tinydrm_dbg_spi_print(spi, tmp, tmp->tx_buf, i, true);
+		if (tmp->rx_buf)
+			tinydrm_dbg_spi_print(spi, tmp, tmp->rx_buf, i, false);
+		i++;
+	}
+}
+EXPORT_SYMBOL(_tinydrm_dbg_spi_message);
+
+/**
+ * tinydrm_spi_transfer - SPI transfer helper
+ * @spi: SPI device
+ * @speed_hz: Override speed (optional)
+ * @header: Optional header transfer
+ * @bpw: Bits per word
+ * @buf: Buffer to transfer
+ * @len: Buffer length
+ *
+ * This SPI transfer helper breaks up the transfer of @buf into chunks which
+ * the SPI master driver can handle. If the machine is Little Endian and the
+ * SPI master driver doesn't support 16 bits per word, it swaps the bytes and
+ * does a 8-bit transfer.
+ * If @header is set, it is prepended to each SPI message.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz,
+			 struct spi_transfer *header, u8 bpw, const void *buf,
+			 size_t len)
+{
+	struct spi_transfer tr = {
+		.bits_per_word = bpw,
+		.speed_hz = speed_hz,
+	};
+	struct spi_message m;
+	u16 *swap_buf = NULL;
+	size_t max_chunk;
+	size_t chunk;
+	int ret = 0;
+
+	if (WARN_ON_ONCE(bpw != 8 && bpw != 16))
+		return -EINVAL;
+
+	max_chunk = tinydrm_spi_max_transfer_size(spi, 0);
+
+	if (drm_debug & DRM_UT_DRIVER)
+		pr_debug("[drm:%s] bpw=%u, max_chunk=%zu, transfers:\n",
+			 __func__, bpw, max_chunk);
+
+	if (bpw == 16 && !tinydrm_spi_bpw_supported(spi, 16)) {
+		tr.bits_per_word = 8;
+		if (tinydrm_machine_little_endian()) {
+			swap_buf = kmalloc(min(len, max_chunk), GFP_KERNEL);
+			if (!swap_buf)
+				return -ENOMEM;
+		}
+	}
+
+	spi_message_init(&m);
+	if (header)
+		spi_message_add_tail(header, &m);
+	spi_message_add_tail(&tr, &m);
+
+	while (len) {
+		chunk = min(len, max_chunk);
+
+		tr.tx_buf = buf;
+		tr.len = chunk;
+
+		if (swap_buf) {
+			const u16 *buf16 = buf;
+			unsigned int i;
+
+			for (i = 0; i < chunk / 2; i++)
+				swap_buf[i] = swab16(buf16[i]);
+
+			tr.tx_buf = swap_buf;
+		}
+
+		buf += chunk;
+		len -= chunk;
+
+		tinydrm_dbg_spi_message(spi, &m);
+		ret = spi_sync(spi, &m);
+		if (ret)
+			return ret;
+	};
+
+	return 0;
+}
+EXPORT_SYMBOL(tinydrm_spi_transfer);
+
+#endif /* CONFIG_SPI */
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c b/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
new file mode 100644
index 000000000000..ec43fb7ad9e4
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 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 <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_modes.h>
+#include <drm/tinydrm/tinydrm.h>
+
+struct tinydrm_connector {
+	struct drm_connector base;
+	const struct drm_display_mode *mode;
+};
+
+static inline struct tinydrm_connector *
+to_tinydrm_connector(struct drm_connector *connector)
+{
+	return container_of(connector, struct tinydrm_connector, base);
+}
+
+static int tinydrm_connector_get_modes(struct drm_connector *connector)
+{
+	struct tinydrm_connector *tconn = to_tinydrm_connector(connector);
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(connector->dev, tconn->mode);
+	if (!mode) {
+		DRM_ERROR("Failed to duplicate mode\n");
+		return 0;
+	}
+
+	if (mode->name[0] == '\0')
+		drm_mode_set_name(mode);
+
+	mode->type |= DRM_MODE_TYPE_PREFERRED;
+	drm_mode_probed_add(connector, mode);
+
+	if (mode->width_mm) {
+		connector->display_info.width_mm = mode->width_mm;
+		connector->display_info.height_mm = mode->height_mm;
+	}
+
+	return 1;
+}
+
+static const struct drm_connector_helper_funcs tinydrm_connector_hfuncs = {
+	.get_modes = tinydrm_connector_get_modes,
+	.best_encoder = drm_atomic_helper_best_encoder,
+};
+
+static enum drm_connector_status
+tinydrm_connector_detect(struct drm_connector *connector, bool force)
+{
+	if (drm_device_is_unplugged(connector->dev))
+		return connector_status_disconnected;
+
+	return connector->status;
+}
+
+static void tinydrm_connector_destroy(struct drm_connector *connector)
+{
+	struct tinydrm_connector *tconn = to_tinydrm_connector(connector);
+
+	drm_connector_cleanup(connector);
+	kfree(tconn);
+}
+
+static const struct drm_connector_funcs tinydrm_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.reset = drm_atomic_helper_connector_reset,
+	.detect = tinydrm_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = tinydrm_connector_destroy,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+struct drm_connector *
+tinydrm_connector_create(struct drm_device *drm,
+			 const struct drm_display_mode *mode,
+			 int connector_type)
+{
+	struct tinydrm_connector *tconn;
+	struct drm_connector *connector;
+	int ret;
+
+	tconn = kzalloc(sizeof(*tconn), GFP_KERNEL);
+	if (!tconn)
+		return ERR_PTR(-ENOMEM);
+
+	tconn->mode = mode;
+	connector = &tconn->base;
+
+	drm_connector_helper_add(connector, &tinydrm_connector_hfuncs);
+	ret = drm_connector_init(drm, connector, &tinydrm_connector_funcs,
+				 connector_type);
+	if (ret) {
+		kfree(tconn);
+		return ERR_PTR(ret);
+	}
+
+	connector->status = connector_status_connected;
+
+	return connector;
+}
+
+/**
+ * tinydrm_display_pipe_update - Display pipe update helper
+ * @pipe: Simple display pipe
+ * @old_state: Old plane state
+ *
+ * This function does a full framebuffer flush if the plane framebuffer
+ * has changed. It also handles vblank events. Drivers can use this as their
+ * &drm_simple_display_pipe_funcs->update callback.
+ */
+void tinydrm_display_pipe_update(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *old_state)
+{
+	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+	struct drm_framebuffer *fb = pipe->plane.state->fb;
+	struct drm_crtc *crtc = &tdev->pipe.crtc;
+
+	if (fb && (fb != old_state->fb)) {
+		pipe->plane.fb = fb;
+		if (fb->funcs->dirty)
+			fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
+	}
+
+	if (crtc->state->event) {
+		spin_lock_irq(&crtc->dev->event_lock);
+		drm_crtc_send_vblank_event(crtc, crtc->state->event);
+		spin_unlock_irq(&crtc->dev->event_lock);
+		crtc->state->event = NULL;
+	}
+}
+EXPORT_SYMBOL(tinydrm_display_pipe_update);
+
+/**
+ * tinydrm_display_pipe_prepare_fb - Display pipe prepare_fb helper
+ * @pipe: Simple display pipe
+ * @plane_state: Plane state
+ *
+ * This function uses drm_fb_cma_prepare_fb() to check if the plane FB has an
+ * dma-buf attached, extracts the exclusive fence and attaches it to plane
+ * state for the atomic helper to wait on. Drivers can use this as their
+ * &drm_simple_display_pipe_funcs->prepare_fb callback.
+ */
+int tinydrm_display_pipe_prepare_fb(struct drm_simple_display_pipe *pipe,
+				    struct drm_plane_state *plane_state)
+{
+	return drm_fb_cma_prepare_fb(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(tinydrm_display_pipe_prepare_fb);
+
+static int tinydrm_rotate_mode(struct drm_display_mode *mode,
+			       unsigned int rotation)
+{
+	if (rotation == 0 || rotation == 180) {
+		return 0;
+	} else if (rotation == 90 || rotation == 270) {
+		swap(mode->hdisplay, mode->vdisplay);
+		swap(mode->hsync_start, mode->vsync_start);
+		swap(mode->hsync_end, mode->vsync_end);
+		swap(mode->htotal, mode->vtotal);
+		swap(mode->width_mm, mode->height_mm);
+		return 0;
+	} else {
+		return -EINVAL;
+	}
+}
+
+/**
+ * tinydrm_display_pipe_init - Initialize display pipe
+ * @tdev: tinydrm device
+ * @funcs: Display pipe functions
+ * @connector_type: Connector type
+ * @formats: Array of supported formats (DRM_FORMAT\_\*)
+ * @format_count: Number of elements in @formats
+ * @mode: Supported mode
+ * @rotation: Initial @mode rotation in degrees Counter Clock Wise
+ *
+ * This function sets up a &drm_simple_display_pipe with a &drm_connector that
+ * has one fixed &drm_display_mode which is rotated according to @rotation.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int
+tinydrm_display_pipe_init(struct tinydrm_device *tdev,
+			  const struct drm_simple_display_pipe_funcs *funcs,
+			  int connector_type,
+			  const uint32_t *formats,
+			  unsigned int format_count,
+			  const struct drm_display_mode *mode,
+			  unsigned int rotation)
+{
+	struct drm_device *drm = tdev->drm;
+	struct drm_display_mode *mode_copy;
+	struct drm_connector *connector;
+	int ret;
+
+	mode_copy = devm_kmalloc(drm->dev, sizeof(*mode_copy), GFP_KERNEL);
+	if (!mode_copy)
+		return -ENOMEM;
+
+	*mode_copy = *mode;
+	ret = tinydrm_rotate_mode(mode_copy, rotation);
+	if (ret) {
+		DRM_ERROR("Illegal rotation value %u\n", rotation);
+		return -EINVAL;
+	}
+
+	drm->mode_config.min_width = mode_copy->hdisplay;
+	drm->mode_config.max_width = mode_copy->hdisplay;
+	drm->mode_config.min_height = mode_copy->vdisplay;
+	drm->mode_config.max_height = mode_copy->vdisplay;
+
+	connector = tinydrm_connector_create(drm, mode_copy, connector_type);
+	if (IS_ERR(connector))
+		return PTR_ERR(connector);
+
+	ret = drm_simple_display_pipe_init(drm, &tdev->pipe, funcs, formats,
+					   format_count, connector);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(tinydrm_display_pipe_init);
diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
new file mode 100644
index 000000000000..b29fe86158f7
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
@@ -0,0 +1,279 @@
+/*
+ * DRM driver for Multi-Inno MI0283QT panels
+ *
+ * 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 <drm/tinydrm/ili9341.h>
+#include <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+static int mi0283qt_init(struct mipi_dbi *mipi)
+{
+	struct tinydrm_device *tdev = &mipi->tinydrm;
+	struct device *dev = tdev->drm->dev;
+	u8 addr_mode;
+	int ret;
+
+	DRM_DEBUG_KMS("\n");
+
+	ret = regulator_enable(mipi->regulator);
+	if (ret) {
+		dev_err(dev, "Failed to enable regulator %d\n", ret);
+		return ret;
+	}
+
+	/* Avoid flicker by skipping setup if the bootloader has done it */
+	if (mipi_dbi_display_is_on(mipi))
+		return 0;
+
+	mipi_dbi_hw_reset(mipi);
+	ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
+	if (ret) {
+		dev_err(dev, "Error sending command %d\n", ret);
+		regulator_disable(mipi->regulator);
+		return ret;
+	}
+
+	msleep(20);
+
+	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
+
+	mipi_dbi_command(mipi, ILI9341_PWCTRLB, 0x00, 0x83, 0x30);
+	mipi_dbi_command(mipi, ILI9341_PWRSEQ, 0x64, 0x03, 0x12, 0x81);
+	mipi_dbi_command(mipi, ILI9341_DTCTRLA, 0x85, 0x01, 0x79);
+	mipi_dbi_command(mipi, ILI9341_PWCTRLA, 0x39, 0x2c, 0x00, 0x34, 0x02);
+	mipi_dbi_command(mipi, ILI9341_PUMPCTRL, 0x20);
+	mipi_dbi_command(mipi, ILI9341_DTCTRLB, 0x00, 0x00);
+
+	/* Power Control */
+	mipi_dbi_command(mipi, ILI9341_PWCTRL1, 0x26);
+	mipi_dbi_command(mipi, ILI9341_PWCTRL2, 0x11);
+	/* VCOM */
+	mipi_dbi_command(mipi, ILI9341_VMCTRL1, 0x35, 0x3e);
+	mipi_dbi_command(mipi, ILI9341_VMCTRL2, 0xbe);
+
+	/* Memory Access Control */
+	mipi_dbi_command(mipi, MIPI_DCS_SET_PIXEL_FORMAT, 0x55);
+
+	switch (mipi->rotation) {
+	default:
+		addr_mode = ILI9341_MADCTL_MV | ILI9341_MADCTL_MY |
+			    ILI9341_MADCTL_MX;
+		break;
+	case 90:
+		addr_mode = ILI9341_MADCTL_MY;
+		break;
+	case 180:
+		addr_mode = ILI9341_MADCTL_MV;
+		break;
+	case 270:
+		addr_mode = ILI9341_MADCTL_MX;
+		break;
+	}
+	addr_mode |= ILI9341_MADCTL_BGR;
+	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+
+	/* Frame Rate */
+	mipi_dbi_command(mipi, ILI9341_FRMCTR1, 0x00, 0x1b);
+
+	/* Gamma */
+	mipi_dbi_command(mipi, ILI9341_EN3GAM, 0x08);
+	mipi_dbi_command(mipi, MIPI_DCS_SET_GAMMA_CURVE, 0x01);
+	mipi_dbi_command(mipi, ILI9341_PGAMCTRL,
+		       0x1f, 0x1a, 0x18, 0x0a, 0x0f, 0x06, 0x45, 0x87,
+		       0x32, 0x0a, 0x07, 0x02, 0x07, 0x05, 0x00);
+	mipi_dbi_command(mipi, ILI9341_NGAMCTRL,
+		       0x00, 0x25, 0x27, 0x05, 0x10, 0x09, 0x3a, 0x78,
+		       0x4d, 0x05, 0x18, 0x0d, 0x38, 0x3a, 0x1f);
+
+	/* DDRAM */
+	mipi_dbi_command(mipi, ILI9341_ETMOD, 0x07);
+
+	/* Display */
+	mipi_dbi_command(mipi, ILI9341_DISCTRL, 0x0a, 0x82, 0x27, 0x00);
+	mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
+	msleep(100);
+
+	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
+	msleep(100);
+
+	return 0;
+}
+
+static void mi0283qt_fini(void *data)
+{
+	struct mipi_dbi *mipi = data;
+
+	DRM_DEBUG_KMS("\n");
+	regulator_disable(mipi->regulator);
+}
+
+static const struct drm_simple_display_pipe_funcs mi0283qt_pipe_funcs = {
+	.enable = mipi_dbi_pipe_enable,
+	.disable = mipi_dbi_pipe_disable,
+	.update = tinydrm_display_pipe_update,
+	.prepare_fb = tinydrm_display_pipe_prepare_fb,
+};
+
+static const struct drm_display_mode mi0283qt_mode = {
+	TINYDRM_MODE(320, 240, 58, 43),
+};
+
+static struct drm_driver mi0283qt_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
+				  DRIVER_ATOMIC,
+	TINYDRM_GEM_DRIVER_OPS,
+	.lastclose		= tinydrm_lastclose,
+	.debugfs_init		= mipi_dbi_debugfs_init,
+	.name			= "mi0283qt",
+	.desc			= "Multi-Inno MI0283QT",
+	.date			= "20160614",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id mi0283qt_of_match[] = {
+	{ .compatible = "multi-inno,mi0283qt" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mi0283qt_of_match);
+
+static const struct spi_device_id mi0283qt_id[] = {
+	{ "mi0283qt", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, mi0283qt_id);
+
+static int mi0283qt_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct tinydrm_device *tdev;
+	struct mipi_dbi *mipi;
+	struct gpio_desc *dc;
+	u32 rotation = 0;
+	int ret;
+
+	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
+	if (!mipi)
+		return -ENOMEM;
+
+	mipi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(mipi->reset)) {
+		dev_err(dev, "Failed to get gpio 'reset'\n");
+		return PTR_ERR(mipi->reset);
+	}
+
+	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
+	if (IS_ERR(dc)) {
+		dev_err(dev, "Failed to get gpio 'dc'\n");
+		return PTR_ERR(dc);
+	}
+
+	mipi->regulator = devm_regulator_get(dev, "power");
+	if (IS_ERR(mipi->regulator))
+		return PTR_ERR(mipi->regulator);
+
+	mipi->backlight = tinydrm_of_find_backlight(dev);
+	if (IS_ERR(mipi->backlight))
+		return PTR_ERR(mipi->backlight);
+
+	device_property_read_u32(dev, "rotation", &rotation);
+
+	ret = mipi_dbi_spi_init(spi, mipi, dc, &mi0283qt_pipe_funcs,
+				&mi0283qt_driver, &mi0283qt_mode, rotation);
+	if (ret)
+		return ret;
+
+	ret = mi0283qt_init(mipi);
+	if (ret)
+		return ret;
+
+	/* use devres to fini after drm unregister (drv->remove is before) */
+	ret = devm_add_action(dev, mi0283qt_fini, mipi);
+	if (ret) {
+		mi0283qt_fini(mipi);
+		return ret;
+	}
+
+	tdev = &mipi->tinydrm;
+
+	ret = devm_tinydrm_register(tdev);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, mipi);
+
+	DRM_DEBUG_DRIVER("Initialized %s:%s @%uMHz on minor %d\n",
+			 tdev->drm->driver->name, dev_name(dev),
+			 spi->max_speed_hz / 1000000,
+			 tdev->drm->primary->index);
+
+	return 0;
+}
+
+static void mi0283qt_shutdown(struct spi_device *spi)
+{
+	struct mipi_dbi *mipi = spi_get_drvdata(spi);
+
+	tinydrm_shutdown(&mipi->tinydrm);
+}
+
+static int __maybe_unused mi0283qt_pm_suspend(struct device *dev)
+{
+	struct mipi_dbi *mipi = dev_get_drvdata(dev);
+	int ret;
+
+	ret = tinydrm_suspend(&mipi->tinydrm);
+	if (ret)
+		return ret;
+
+	mi0283qt_fini(mipi);
+
+	return 0;
+}
+
+static int __maybe_unused mi0283qt_pm_resume(struct device *dev)
+{
+	struct mipi_dbi *mipi = dev_get_drvdata(dev);
+	int ret;
+
+	ret = mi0283qt_init(mipi);
+	if (ret)
+		return ret;
+
+	return tinydrm_resume(&mipi->tinydrm);
+}
+
+static const struct dev_pm_ops mi0283qt_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mi0283qt_pm_suspend, mi0283qt_pm_resume)
+};
+
+static struct spi_driver mi0283qt_spi_driver = {
+	.driver = {
+		.name = "mi0283qt",
+		.owner = THIS_MODULE,
+		.of_match_table = mi0283qt_of_match,
+		.pm = &mi0283qt_pm_ops,
+	},
+	.id_table = mi0283qt_id,
+	.probe = mi0283qt_probe,
+	.shutdown = mi0283qt_shutdown,
+};
+module_spi_driver(mi0283qt_spi_driver);
+
+MODULE_DESCRIPTION("Multi-Inno MI0283QT DRM driver");
+MODULE_AUTHOR("Noralf Trønnes");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
new file mode 100644
index 000000000000..07d49ba78d8e
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -0,0 +1,1005 @@
+/*
+ * MIPI Display Bus Interface (DBI) LCD controller support
+ *
+ * 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 <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+#include <linux/debugfs.h>
+#include <linux/dma-buf.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+#define MIPI_DBI_MAX_SPI_READ_SPEED 2000000 /* 2MHz */
+
+#define DCS_POWER_MODE_DISPLAY			BIT(2)
+#define DCS_POWER_MODE_DISPLAY_NORMAL_MODE	BIT(3)
+#define DCS_POWER_MODE_SLEEP_MODE		BIT(4)
+#define DCS_POWER_MODE_PARTIAL_MODE		BIT(5)
+#define DCS_POWER_MODE_IDLE_MODE		BIT(6)
+#define DCS_POWER_MODE_RESERVED_MASK		(BIT(0) | BIT(1) | BIT(7))
+
+/**
+ * DOC: overview
+ *
+ * This library provides helpers for MIPI Display Bus Interface (DBI)
+ * compatible display controllers.
+ *
+ * Many controllers for tiny lcd displays are MIPI compliant and can use this
+ * library. If a controller uses registers 0x2A and 0x2B to set the area to
+ * update and uses register 0x2C to write to frame memory, it is most likely
+ * MIPI compliant.
+ *
+ * Only MIPI Type 1 displays are supported since a full frame memory is needed.
+ *
+ * There are 3 MIPI DBI implementation types:
+ *
+ * A. Motorola 6800 type parallel bus
+ *
+ * B. Intel 8080 type parallel bus
+ *
+ * C. SPI type with 3 options:
+ *
+ *    1. 9-bit with the Data/Command signal as the ninth bit
+ *    2. Same as above except it's sent as 16 bits
+ *    3. 8-bit with the Data/Command signal as a separate D/CX pin
+ *
+ * Currently mipi_dbi only supports Type C options 1 and 3 with
+ * mipi_dbi_spi_init().
+ */
+
+#define MIPI_DBI_DEBUG_COMMAND(cmd, data, len) \
+({ \
+	if (!len) \
+		DRM_DEBUG_DRIVER("cmd=%02x\n", cmd); \
+	else if (len <= 32) \
+		DRM_DEBUG_DRIVER("cmd=%02x, par=%*ph\n", cmd, len, data); \
+	else \
+		DRM_DEBUG_DRIVER("cmd=%02x, len=%zu\n", cmd, len); \
+})
+
+static const u8 mipi_dbi_dcs_read_commands[] = {
+	MIPI_DCS_GET_DISPLAY_ID,
+	MIPI_DCS_GET_RED_CHANNEL,
+	MIPI_DCS_GET_GREEN_CHANNEL,
+	MIPI_DCS_GET_BLUE_CHANNEL,
+	MIPI_DCS_GET_DISPLAY_STATUS,
+	MIPI_DCS_GET_POWER_MODE,
+	MIPI_DCS_GET_ADDRESS_MODE,
+	MIPI_DCS_GET_PIXEL_FORMAT,
+	MIPI_DCS_GET_DISPLAY_MODE,
+	MIPI_DCS_GET_SIGNAL_MODE,
+	MIPI_DCS_GET_DIAGNOSTIC_RESULT,
+	MIPI_DCS_READ_MEMORY_START,
+	MIPI_DCS_READ_MEMORY_CONTINUE,
+	MIPI_DCS_GET_SCANLINE,
+	MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+	MIPI_DCS_GET_CONTROL_DISPLAY,
+	MIPI_DCS_GET_POWER_SAVE,
+	MIPI_DCS_GET_CABC_MIN_BRIGHTNESS,
+	MIPI_DCS_READ_DDB_START,
+	MIPI_DCS_READ_DDB_CONTINUE,
+	0, /* sentinel */
+};
+
+static bool mipi_dbi_command_is_read(struct mipi_dbi *mipi, u8 cmd)
+{
+	unsigned int i;
+
+	if (!mipi->read_commands)
+		return false;
+
+	for (i = 0; i < 0xff; i++) {
+		if (!mipi->read_commands[i])
+			return false;
+		if (cmd == mipi->read_commands[i])
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * mipi_dbi_command_read - MIPI DCS read command
+ * @mipi: MIPI structure
+ * @cmd: Command
+ * @val: Value read
+ *
+ * Send MIPI DCS read command to the controller.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_command_read(struct mipi_dbi *mipi, u8 cmd, u8 *val)
+{
+	if (!mipi->read_commands)
+		return -EACCES;
+
+	if (!mipi_dbi_command_is_read(mipi, cmd))
+		return -EINVAL;
+
+	return mipi_dbi_command_buf(mipi, cmd, val, 1);
+}
+EXPORT_SYMBOL(mipi_dbi_command_read);
+
+/**
+ * mipi_dbi_command_buf - MIPI DCS command with parameter(s) in an array
+ * @mipi: MIPI structure
+ * @cmd: Command
+ * @data: Parameter buffer
+ * @len: Buffer length
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len)
+{
+	int ret;
+
+	mutex_lock(&mipi->cmdlock);
+	ret = mipi->command(mipi, cmd, data, len);
+	mutex_unlock(&mipi->cmdlock);
+
+	return ret;
+}
+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)
+{
+	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;
+	struct drm_format_name_buf format_name;
+	void *src = cma_obj->vaddr;
+	int ret = 0;
+
+	if (import_attach) {
+		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
+					       DMA_FROM_DEVICE);
+		if (ret)
+			return ret;
+	}
+
+	switch (fb->format->format) {
+	case DRM_FORMAT_RGB565:
+		if (swap)
+			tinydrm_swab16(dst, src, fb, clip);
+		else
+			tinydrm_memcpy(dst, src, fb, clip);
+		break;
+	case DRM_FORMAT_XRGB8888:
+		tinydrm_xrgb8888_to_rgb565(dst, src, fb, clip, swap);
+		break;
+	default:
+		dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
+			     drm_get_format_name(fb->format->format,
+						 &format_name));
+		return -EINVAL;
+	}
+
+	if (import_attach)
+		ret = dma_buf_end_cpu_access(import_attach->dmabuf,
+					     DMA_FROM_DEVICE);
+	return ret;
+}
+
+static int mipi_dbi_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;
+	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;
+	}
+
+	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
+			 (clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
+			 (clip.x2 >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
+	mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
+			 (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
+			 (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
+
+	ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START, 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 mipi_dbi_fb_funcs = {
+	.destroy	= drm_fb_cma_destroy,
+	.create_handle	= drm_fb_cma_create_handle,
+	.dirty		= mipi_dbi_fb_dirty,
+};
+
+/**
+ * mipi_dbi_pipe_enable - MIPI DBI pipe enable helper
+ * @pipe: Display pipe
+ * @crtc_state: CRTC state
+ *
+ * This function enables backlight. Drivers can use this as their
+ * &drm_simple_display_pipe_funcs->enable callback.
+ */
+void mipi_dbi_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;
+
+	DRM_DEBUG_KMS("\n");
+
+	mipi->enabled = true;
+	if (fb)
+		fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
+
+	tinydrm_enable_backlight(mipi->backlight);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_enable);
+
+static void mipi_dbi_blank(struct mipi_dbi *mipi)
+{
+	struct drm_device *drm = mipi->tinydrm.drm;
+	u16 height = drm->mode_config.min_height;
+	u16 width = drm->mode_config.min_width;
+	size_t len = width * height * 2;
+
+	memset(mipi->tx_buf, 0, len);
+
+	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS, 0, 0,
+			 (width >> 8) & 0xFF, (width - 1) & 0xFF);
+	mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS, 0, 0,
+			 (height >> 8) & 0xFF, (height - 1) & 0xFF);
+	mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
+			     (u8 *)mipi->tx_buf, len);
+}
+
+/**
+ * mipi_dbi_pipe_disable - MIPI DBI pipe disable helper
+ * @pipe: Display pipe
+ *
+ * This function disables backlight if present or if not the
+ * display memory is blanked. Drivers can use this as their
+ * &drm_simple_display_pipe_funcs->disable callback.
+ */
+void mipi_dbi_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");
+
+	mipi->enabled = false;
+
+	if (mipi->backlight)
+		tinydrm_disable_backlight(mipi->backlight);
+	else
+		mipi_dbi_blank(mipi);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_disable);
+
+static const uint32_t mipi_dbi_formats[] = {
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_XRGB8888,
+};
+
+/**
+ * mipi_dbi_init - MIPI DBI initialization
+ * @dev: Parent device
+ * @mipi: &mipi_dbi structure to initialize
+ * @pipe_funcs: Display pipe functions
+ * @driver: DRM driver
+ * @mode: Display mode
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ *
+ * This function initializes a &mipi_dbi structure and it's underlying
+ * @tinydrm_device. It also sets up the display pipeline.
+ *
+ * Supported formats: Native RGB565 and emulated XRGB8888.
+ *
+ * Objects created by this function will be automatically freed on driver
+ * detach (devres).
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_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, &mipi_dbi_fb_funcs, driver);
+	if (ret)
+		return ret;
+
+	/* TODO: Maybe add DRM_MODE_CONNECTOR_SPI */
+	ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
+					DRM_MODE_CONNECTOR_VIRTUAL,
+					mipi_dbi_formats,
+					ARRAY_SIZE(mipi_dbi_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;
+}
+EXPORT_SYMBOL(mipi_dbi_init);
+
+/**
+ * mipi_dbi_hw_reset - Hardware reset of controller
+ * @mipi: MIPI DBI structure
+ *
+ * Reset controller if the &mipi_dbi->reset gpio is set.
+ */
+void mipi_dbi_hw_reset(struct mipi_dbi *mipi)
+{
+	if (!mipi->reset)
+		return;
+
+	gpiod_set_value_cansleep(mipi->reset, 0);
+	msleep(20);
+	gpiod_set_value_cansleep(mipi->reset, 1);
+	msleep(120);
+}
+EXPORT_SYMBOL(mipi_dbi_hw_reset);
+
+/**
+ * mipi_dbi_display_is_on - Check if display is on
+ * @mipi: MIPI DBI structure
+ *
+ * This function checks the Power Mode register (if readable) to see if
+ * display output is turned on. This can be used to see if the bootloader
+ * has already turned on the display avoiding flicker when the pipeline is
+ * enabled.
+ *
+ * Returns:
+ * true if the display can be verified to be on, false otherwise.
+ */
+bool mipi_dbi_display_is_on(struct mipi_dbi *mipi)
+{
+	u8 val;
+
+	if (mipi_dbi_command_read(mipi, MIPI_DCS_GET_POWER_MODE, &val))
+		return false;
+
+	val &= ~DCS_POWER_MODE_RESERVED_MASK;
+
+	if (val != (DCS_POWER_MODE_DISPLAY |
+	    DCS_POWER_MODE_DISPLAY_NORMAL_MODE | DCS_POWER_MODE_SLEEP_MODE))
+		return false;
+
+	DRM_DEBUG_DRIVER("Display is ON\n");
+
+	return true;
+}
+EXPORT_SYMBOL(mipi_dbi_display_is_on);
+
+#if IS_ENABLED(CONFIG_SPI)
+
+/*
+ * 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)
+{
+	if (len > 64)
+		return 0; /* use default */
+
+	return min_t(u32, 10000000, spi->max_speed_hz);
+}
+
+/*
+ * MIPI DBI Type C Option 1
+ *
+ * If the SPI controller doesn't have 9 bits per word support,
+ * use blocks of 9 bytes to send 8x 9-bit words using a 8-bit SPI transfer.
+ * Pad partial blocks with MIPI_DCS_NOP (zero).
+ * This is how the D/C bit (x) is added:
+ *     x7654321
+ *     0x765432
+ *     10x76543
+ *     210x7654
+ *     3210x765
+ *     43210x76
+ *     543210x7
+ *     6543210x
+ *     76543210
+ */
+
+static int mipi_dbi_spi1e_transfer(struct mipi_dbi *mipi, int dc,
+				   const void *buf, size_t len,
+				   unsigned int bpw)
+{
+	bool swap_bytes = (bpw == 16 && tinydrm_machine_little_endian());
+	size_t chunk, max_chunk = mipi->tx_buf9_len;
+	struct spi_device *spi = mipi->spi;
+	struct spi_transfer tr = {
+		.tx_buf = mipi->tx_buf9,
+		.bits_per_word = 8,
+	};
+	struct spi_message m;
+	const u8 *src = buf;
+	int i, ret;
+	u8 *dst;
+
+	if (drm_debug & DRM_UT_DRIVER)
+		pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
+			 __func__, dc, max_chunk);
+
+	tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
+	spi_message_init_with_transfers(&m, &tr, 1);
+
+	if (!dc) {
+		if (WARN_ON_ONCE(len != 1))
+			return -EINVAL;
+
+		/* Command: pad no-op's (zeroes) at beginning of block */
+		dst = mipi->tx_buf9;
+		memset(dst, 0, 9);
+		dst[8] = *src;
+		tr.len = 9;
+
+		tinydrm_dbg_spi_message(spi, &m);
+
+		return spi_sync(spi, &m);
+	}
+
+	/* max with room for adding one bit per byte */
+	max_chunk = max_chunk / 9 * 8;
+	/* but no bigger than len */
+	max_chunk = min(max_chunk, len);
+	/* 8 byte blocks */
+	max_chunk = max_t(size_t, 8, max_chunk & ~0x7);
+
+	while (len) {
+		size_t added = 0;
+
+		chunk = min(len, max_chunk);
+		len -= chunk;
+		dst = mipi->tx_buf9;
+
+		if (chunk < 8) {
+			u8 val, carry = 0;
+
+			/* Data: pad no-op's (zeroes) at end of block */
+			memset(dst, 0, 9);
+
+			if (swap_bytes) {
+				for (i = 1; i < (chunk + 1); i++) {
+					val = src[1];
+					*dst++ = carry | BIT(8 - i) | (val >> i);
+					carry = val << (8 - i);
+					i++;
+					val = src[0];
+					*dst++ = carry | BIT(8 - i) | (val >> i);
+					carry = val << (8 - i);
+					src += 2;
+				}
+				*dst++ = carry;
+			} else {
+				for (i = 1; i < (chunk + 1); i++) {
+					val = *src++;
+					*dst++ = carry | BIT(8 - i) | (val >> i);
+					carry = val << (8 - i);
+				}
+				*dst++ = carry;
+			}
+
+			chunk = 8;
+			added = 1;
+		} else {
+			for (i = 0; i < chunk; i += 8) {
+				if (swap_bytes) {
+					*dst++ =                 BIT(7) | (src[1] >> 1);
+					*dst++ = (src[1] << 7) | BIT(6) | (src[0] >> 2);
+					*dst++ = (src[0] << 6) | BIT(5) | (src[3] >> 3);
+					*dst++ = (src[3] << 5) | BIT(4) | (src[2] >> 4);
+					*dst++ = (src[2] << 4) | BIT(3) | (src[5] >> 5);
+					*dst++ = (src[5] << 3) | BIT(2) | (src[4] >> 6);
+					*dst++ = (src[4] << 2) | BIT(1) | (src[7] >> 7);
+					*dst++ = (src[7] << 1) | BIT(0);
+					*dst++ = src[6];
+				} else {
+					*dst++ =                 BIT(7) | (src[0] >> 1);
+					*dst++ = (src[0] << 7) | BIT(6) | (src[1] >> 2);
+					*dst++ = (src[1] << 6) | BIT(5) | (src[2] >> 3);
+					*dst++ = (src[2] << 5) | BIT(4) | (src[3] >> 4);
+					*dst++ = (src[3] << 4) | BIT(3) | (src[4] >> 5);
+					*dst++ = (src[4] << 3) | BIT(2) | (src[5] >> 6);
+					*dst++ = (src[5] << 2) | BIT(1) | (src[6] >> 7);
+					*dst++ = (src[6] << 1) | BIT(0);
+					*dst++ = src[7];
+				}
+
+				src += 8;
+				added++;
+			}
+		}
+
+		tr.len = chunk + added;
+
+		tinydrm_dbg_spi_message(spi, &m);
+		ret = spi_sync(spi, &m);
+		if (ret)
+			return ret;
+	};
+
+	return 0;
+}
+
+static int mipi_dbi_spi1_transfer(struct mipi_dbi *mipi, int dc,
+				  const void *buf, size_t len,
+				  unsigned int bpw)
+{
+	struct spi_device *spi = mipi->spi;
+	struct spi_transfer tr = {
+		.bits_per_word = 9,
+	};
+	const u16 *src16 = buf;
+	const u8 *src8 = buf;
+	struct spi_message m;
+	size_t max_chunk;
+	u16 *dst16;
+	int ret;
+
+	if (!tinydrm_spi_bpw_supported(spi, 9))
+		return mipi_dbi_spi1e_transfer(mipi, dc, buf, len, bpw);
+
+	tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
+	max_chunk = mipi->tx_buf9_len;
+	dst16 = mipi->tx_buf9;
+
+	if (drm_debug & DRM_UT_DRIVER)
+		pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
+			 __func__, dc, max_chunk);
+
+	max_chunk = min(max_chunk / 2, len);
+
+	spi_message_init_with_transfers(&m, &tr, 1);
+	tr.tx_buf = dst16;
+
+	while (len) {
+		size_t chunk = min(len, max_chunk);
+		unsigned int i;
+
+		if (bpw == 16 && tinydrm_machine_little_endian()) {
+			for (i = 0; i < (chunk * 2); i += 2) {
+				dst16[i]     = *src16 >> 8;
+				dst16[i + 1] = *src16++ & 0xFF;
+				if (dc) {
+					dst16[i]     |= 0x0100;
+					dst16[i + 1] |= 0x0100;
+				}
+			}
+		} else {
+			for (i = 0; i < chunk; i++) {
+				dst16[i] = *src8++;
+				if (dc)
+					dst16[i] |= 0x0100;
+			}
+		}
+
+		tr.len = chunk;
+		len -= chunk;
+
+		tinydrm_dbg_spi_message(spi, &m);
+		ret = spi_sync(spi, &m);
+		if (ret)
+			return ret;
+	};
+
+	return 0;
+}
+
+static int mipi_dbi_typec1_command(struct mipi_dbi *mipi, u8 cmd,
+				   u8 *parameters, size_t num)
+{
+	unsigned int bpw = (cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
+	int ret;
+
+	if (mipi_dbi_command_is_read(mipi, cmd))
+		return -ENOTSUPP;
+
+	MIPI_DBI_DEBUG_COMMAND(cmd, parameters, num);
+
+	ret = mipi_dbi_spi1_transfer(mipi, 0, &cmd, 1, 8);
+	if (ret || !num)
+		return ret;
+
+	return mipi_dbi_spi1_transfer(mipi, 1, parameters, num, bpw);
+}
+
+/* MIPI DBI Type C Option 3 */
+
+static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
+					u8 *data, size_t len)
+{
+	struct spi_device *spi = mipi->spi;
+	u32 speed_hz = min_t(u32, MIPI_DBI_MAX_SPI_READ_SPEED,
+			     spi->max_speed_hz / 2);
+	struct spi_transfer tr[2] = {
+		{
+			.speed_hz = speed_hz,
+			.tx_buf = &cmd,
+			.len = 1,
+		}, {
+			.speed_hz = speed_hz,
+			.len = len,
+		},
+	};
+	struct spi_message m;
+	u8 *buf;
+	int ret;
+
+	if (!len)
+		return -EINVAL;
+
+	/*
+	 * Support non-standard 24-bit and 32-bit Nokia read commands which
+	 * start with a dummy clock, so we need to read an extra byte.
+	 */
+	if (cmd == MIPI_DCS_GET_DISPLAY_ID ||
+	    cmd == MIPI_DCS_GET_DISPLAY_STATUS) {
+		if (!(len == 3 || len == 4))
+			return -EINVAL;
+
+		tr[1].len = len + 1;
+	}
+
+	buf = kmalloc(tr[1].len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tr[1].rx_buf = buf;
+	gpiod_set_value_cansleep(mipi->dc, 0);
+
+	spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
+	ret = spi_sync(spi, &m);
+	if (ret)
+		goto err_free;
+
+	tinydrm_dbg_spi_message(spi, &m);
+
+	if (tr[1].len == len) {
+		memcpy(data, buf, len);
+	} else {
+		unsigned int i;
+
+		for (i = 0; i < len; i++)
+			data[i] = (buf[i] << 1) | !!(buf[i + 1] & BIT(7));
+	}
+
+	MIPI_DBI_DEBUG_COMMAND(cmd, data, len);
+
+err_free:
+	kfree(buf);
+
+	return ret;
+}
+
+static int mipi_dbi_typec3_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;
+
+	if (mipi_dbi_command_is_read(mipi, cmd))
+		return mipi_dbi_typec3_command_read(mipi, cmd, par, num);
+
+	MIPI_DBI_DEBUG_COMMAND(cmd, par, num);
+
+	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 == MIPI_DCS_WRITE_MEMORY_START && !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);
+}
+
+/**
+ * mipi_dbi_spi_init - Initialize MIPI DBI SPI interfaced controller
+ * @spi: SPI device
+ * @dc: D/C gpio (optional)
+ * @mipi: &mipi_dbi structure to initialize
+ * @pipe_funcs: Display pipe functions
+ * @driver: DRM driver
+ * @mode: Display mode
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ *
+ * This function sets &mipi_dbi->command, enables &mipi->read_commands for the
+ * usual read commands and initializes @mipi using mipi_dbi_init().
+ *
+ * If @dc is set, a Type C Option 3 interface is assumed, if not
+ * Type C Option 1.
+ *
+ * If the SPI master driver doesn't support the necessary bits per word,
+ * the following transformation is used:
+ *
+ * - 9-bit: reorder buffer as 9x 8-bit words, padded with no-op command.
+ * - 16-bit: if big endian send as 8-bit, if little endian swap bytes
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi,
+		      struct gpio_desc *dc,
+		      const struct drm_simple_display_pipe_funcs *pipe_funcs,
+		      struct drm_driver *driver,
+		      const struct drm_display_mode *mode,
+		      unsigned int rotation)
+{
+	size_t tx_size = tinydrm_spi_max_transfer_size(spi, 0);
+	struct device *dev = &spi->dev;
+	int ret;
+
+	if (tx_size < 16) {
+		DRM_ERROR("SPI transmit buffer too small: %zu\n", tx_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * Even though it's not the SPI device that does DMA (the master does),
+	 * the dma mask is necessary for the dma_alloc_wc() in
+	 * drm_gem_cma_create(). The dma_addr returned will be a physical
+	 * adddress which might be different from the bus address, but this is
+	 * not a problem since the address will not be used.
+	 * The virtual address is used in the transfer and the SPI core
+	 * re-maps it on the SPI master device using the DMA streaming API
+	 * (spi_map_buf()).
+	 */
+	if (!dev->coherent_dma_mask) {
+		ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
+		if (ret) {
+			dev_warn(dev, "Failed to set dma mask %d\n", ret);
+			return ret;
+		}
+	}
+
+	mipi->spi = spi;
+	mipi->read_commands = mipi_dbi_dcs_read_commands;
+
+	if (dc) {
+		mipi->command = mipi_dbi_typec3_command;
+		mipi->dc = dc;
+		if (tinydrm_machine_little_endian() &&
+		    !tinydrm_spi_bpw_supported(spi, 16))
+			mipi->swap_bytes = true;
+	} else {
+		mipi->command = mipi_dbi_typec1_command;
+		mipi->tx_buf9_len = tx_size;
+		mipi->tx_buf9 = devm_kmalloc(dev, tx_size, GFP_KERNEL);
+		if (!mipi->tx_buf9)
+			return -ENOMEM;
+	}
+
+	return mipi_dbi_init(dev, mipi, pipe_funcs, driver, mode, rotation);
+}
+EXPORT_SYMBOL(mipi_dbi_spi_init);
+
+#endif /* CONFIG_SPI */
+
+#ifdef CONFIG_DEBUG_FS
+
+static ssize_t mipi_dbi_debugfs_command_write(struct file *file,
+					      const char __user *ubuf,
+					      size_t count, loff_t *ppos)
+{
+	struct seq_file *m = file->private_data;
+	struct mipi_dbi *mipi = m->private;
+	u8 val, cmd, parameters[64];
+	char *buf, *pos, *token;
+	unsigned int i;
+	int ret;
+
+	buf = memdup_user_nul(ubuf, count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	/* strip trailing whitespace */
+	for (i = count - 1; i > 0; i--)
+		if (isspace(buf[i]))
+			buf[i] = '\0';
+		else
+			break;
+	i = 0;
+	pos = buf;
+	while (pos) {
+		token = strsep(&pos, " ");
+		if (!token) {
+			ret = -EINVAL;
+			goto err_free;
+		}
+
+		ret = kstrtou8(token, 16, &val);
+		if (ret < 0)
+			goto err_free;
+
+		if (token == buf)
+			cmd = val;
+		else
+			parameters[i++] = val;
+
+		if (i == 64) {
+			ret = -E2BIG;
+			goto err_free;
+		}
+	}
+
+	ret = mipi_dbi_command_buf(mipi, cmd, parameters, i);
+
+err_free:
+	kfree(buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
+{
+	struct mipi_dbi *mipi = m->private;
+	u8 cmd, val[4];
+	size_t len, i;
+	int ret;
+
+	for (cmd = 0; cmd < 255; cmd++) {
+		if (!mipi_dbi_command_is_read(mipi, cmd))
+			continue;
+
+		switch (cmd) {
+		case MIPI_DCS_READ_MEMORY_START:
+		case MIPI_DCS_READ_MEMORY_CONTINUE:
+			len = 2;
+			break;
+		case MIPI_DCS_GET_DISPLAY_ID:
+			len = 3;
+			break;
+		case MIPI_DCS_GET_DISPLAY_STATUS:
+			len = 4;
+			break;
+		default:
+			len = 1;
+			break;
+		}
+
+		seq_printf(m, "%02x: ", cmd);
+		ret = mipi_dbi_command_buf(mipi, cmd, val, len);
+		if (ret) {
+			seq_puts(m, "XX\n");
+			continue;
+		}
+
+		for (i = 0; i < len; i++)
+			seq_printf(m, "%02x", val[i]);
+		seq_puts(m, "\n");
+	}
+
+	return 0;
+}
+
+static int mipi_dbi_debugfs_command_open(struct inode *inode,
+					 struct file *file)
+{
+	return single_open(file, mipi_dbi_debugfs_command_show,
+			   inode->i_private);
+}
+
+static const struct file_operations mipi_dbi_debugfs_command_fops = {
+	.owner = THIS_MODULE,
+	.open = mipi_dbi_debugfs_command_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = mipi_dbi_debugfs_command_write,
+};
+
+static const struct drm_info_list mipi_dbi_debugfs_list[] = {
+	{ "fb",   drm_fb_cma_debugfs_show, 0 },
+};
+
+/**
+ * mipi_dbi_debugfs_init - Create debugfs entries
+ * @minor: DRM minor
+ *
+ * This function creates a 'command' debugfs file for sending commands to the
+ * controller or getting the read command values.
+ * Drivers can use this as their &drm_driver->debugfs_init callback.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_debugfs_init(struct drm_minor *minor)
+{
+	struct tinydrm_device *tdev = minor->dev->dev_private;
+	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+	umode_t mode = S_IFREG | S_IWUSR;
+
+	if (mipi->read_commands)
+		mode |= S_IRUGO;
+	debugfs_create_file("command", mode, minor->debugfs_root, mipi,
+			    &mipi_dbi_debugfs_command_fops);
+
+	return drm_debugfs_create_files(mipi_dbi_debugfs_list,
+					ARRAY_SIZE(mipi_dbi_debugfs_list),
+					minor->debugfs_root, minor);
+}
+EXPORT_SYMBOL(mipi_dbi_debugfs_init);
+
+#endif
+
+MODULE_LICENSE("GPL");