xref: /openbmc/linux/drivers/gpu/drm/tiny/ofdrm.c (revision c8a17756c42581ba1a567d1dd3b69e8f5619a7d8)

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/platform_device.h>

#include <drm/drm_aperture.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_connector.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_format_helper.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_managed.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>

#define DRIVER_NAME	"ofdrm"
#define DRIVER_DESC	"DRM driver for OF platform devices"
#define DRIVER_DATE	"20220501"
#define DRIVER_MAJOR	1
#define DRIVER_MINOR	0

/*
 * Helpers for display nodes
 */

static int display_get_validated_int(struct drm_device *dev, const char *name, uint32_t value)
{
	if (value > INT_MAX) {
		drm_err(dev, "invalid framebuffer %s of %u\n", name, value);
		return -EINVAL;
	}
	return (int)value;
}

static int display_get_validated_int0(struct drm_device *dev, const char *name, uint32_t value)
{
	if (!value) {
		drm_err(dev, "invalid framebuffer %s of %u\n", name, value);
		return -EINVAL;
	}
	return display_get_validated_int(dev, name, value);
}

static const struct drm_format_info *display_get_validated_format(struct drm_device *dev,
								  u32 depth)
{
	const struct drm_format_info *info;
	u32 format;

	switch (depth) {
	case 8:
		format = drm_mode_legacy_fb_format(8, 8);
		break;
	case 15:
	case 16:
		format = drm_mode_legacy_fb_format(16, depth);
		break;
	case 32:
		format = drm_mode_legacy_fb_format(32, 24);
		break;
	default:
		drm_err(dev, "unsupported framebuffer depth %u\n", depth);
		return ERR_PTR(-EINVAL);
	}

	info = drm_format_info(format);
	if (!info) {
		drm_err(dev, "cannot find framebuffer format for depth %u\n", depth);
		return ERR_PTR(-EINVAL);
	}

	return info;
}

static int display_read_u32_of(struct drm_device *dev, struct device_node *of_node,
			       const char *name, u32 *value)
{
	int ret = of_property_read_u32(of_node, name, value);

	if (ret)
		drm_err(dev, "cannot parse framebuffer %s: error %d\n", name, ret);
	return ret;
}

static int display_get_width_of(struct drm_device *dev, struct device_node *of_node)
{
	u32 width;
	int ret = display_read_u32_of(dev, of_node, "width", &width);

	if (ret)
		return ret;
	return display_get_validated_int0(dev, "width", width);
}

static int display_get_height_of(struct drm_device *dev, struct device_node *of_node)
{
	u32 height;
	int ret = display_read_u32_of(dev, of_node, "height", &height);

	if (ret)
		return ret;
	return display_get_validated_int0(dev, "height", height);
}

static int display_get_depth_of(struct drm_device *dev, struct device_node *of_node)
{
	u32 depth;
	int ret = display_read_u32_of(dev, of_node, "depth", &depth);

	if (ret)
		return ret;
	return display_get_validated_int0(dev, "depth", depth);
}

static int display_get_linebytes_of(struct drm_device *dev, struct device_node *of_node)
{
	u32 linebytes;
	int ret = display_read_u32_of(dev, of_node, "linebytes", &linebytes);

	if (ret)
		return ret;
	return display_get_validated_int(dev, "linebytes", linebytes);
}

static u64 display_get_address_of(struct drm_device *dev, struct device_node *of_node)
{
	u32 address;
	int ret;

	/*
	 * Not all devices provide an address property, it's not
	 * a bug if this fails. The driver will try to find the
	 * framebuffer base address from the device's memory regions.
	 */
	ret = of_property_read_u32(of_node, "address", &address);
	if (ret)
		return OF_BAD_ADDR;

	return address;
}

/*
 * Open Firmware display device
 */

struct ofdrm_device {
	struct drm_device dev;
	struct platform_device *pdev;

	/* firmware-buffer settings */
	struct iosys_map screen_base;
	struct drm_display_mode mode;
	const struct drm_format_info *format;
	unsigned int pitch;

	/* modesetting */
	uint32_t formats[8];
	struct drm_plane primary_plane;
	struct drm_crtc crtc;
	struct drm_encoder encoder;
	struct drm_connector connector;
};

static struct ofdrm_device *ofdrm_device_of_dev(struct drm_device *dev)
{
	return container_of(dev, struct ofdrm_device, dev);
}

/*
 * Hardware
 */

#if defined(CONFIG_PCI)
static struct pci_dev *display_get_pci_dev_of(struct drm_device *dev, struct device_node *of_node)
{
	const __be32 *vendor_p, *device_p;
	u32 vendor, device;
	struct pci_dev *pcidev;

	vendor_p = of_get_property(of_node, "vendor-id", NULL);
	if (!vendor_p)
		return ERR_PTR(-ENODEV);
	vendor = be32_to_cpup(vendor_p);

	device_p = of_get_property(of_node, "device-id", NULL);
	if (!device_p)
		return ERR_PTR(-ENODEV);
	device = be32_to_cpup(device_p);

	pcidev = pci_get_device(vendor, device, NULL);
	if (!pcidev)
		return ERR_PTR(-ENODEV);

	return pcidev;
}

static void ofdrm_pci_release(void *data)
{
	struct pci_dev *pcidev = data;

	pci_disable_device(pcidev);
}

static int ofdrm_device_init_pci(struct ofdrm_device *odev)
{
	struct drm_device *dev = &odev->dev;
	struct platform_device *pdev = to_platform_device(dev->dev);
	struct device_node *of_node = pdev->dev.of_node;
	struct pci_dev *pcidev;
	int ret;

	/*
	 * Never use pcim_ or other managed helpers on the returned PCI
	 * device. Otherwise, probing the native driver will fail for
	 * resource conflicts. PCI-device management has to be tied to
	 * the lifetime of the platform device until the native driver
	 * takes over.
	 */
	pcidev = display_get_pci_dev_of(dev, of_node);
	if (IS_ERR(pcidev))
		return 0; /* no PCI device found; ignore the error */

	ret = pci_enable_device(pcidev);
	if (ret) {
		drm_err(dev, "pci_enable_device(%s) failed: %d\n",
			dev_name(&pcidev->dev), ret);
		return ret;
	}
	ret = devm_add_action_or_reset(&pdev->dev, ofdrm_pci_release, pcidev);
	if (ret)
		return ret;

	return 0;
}
#else
static int ofdrm_device_init_pci(struct ofdrm_device *odev)
{
	return 0;
}
#endif

/*
 *  OF display settings
 */

static struct resource *ofdrm_find_fb_resource(struct ofdrm_device *odev,
					       struct resource *fb_res)
{
	struct platform_device *pdev = to_platform_device(odev->dev.dev);
	struct resource *res, *max_res = NULL;
	u32 i;

	for (i = 0; pdev->num_resources; ++i) {
		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
		if (!res)
			break; /* all resources processed */
		if (resource_size(res) < resource_size(fb_res))
			continue; /* resource too small */
		if (fb_res->start && resource_contains(res, fb_res))
			return res; /* resource contains framebuffer */
		if (!max_res || resource_size(res) > resource_size(max_res))
			max_res = res; /* store largest resource as fallback */
	}

	return max_res;
}

/*
 * Modesetting
 */

/*
 * Support all formats of OF display and maybe more; in order
 * of preference. The display's update function will do any
 * conversion necessary.
 *
 * TODO: Add blit helpers for remaining formats and uncomment
 *       constants.
 */
static const uint32_t ofdrm_primary_plane_formats[] = {
	DRM_FORMAT_XRGB8888,
	DRM_FORMAT_RGB565,
	//DRM_FORMAT_XRGB1555,
	//DRM_FORMAT_C8,
};

static const uint64_t ofdrm_primary_plane_format_modifiers[] = {
	DRM_FORMAT_MOD_LINEAR,
	DRM_FORMAT_MOD_INVALID
};

static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
						   struct drm_atomic_state *new_state)
{
	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_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(new_state, new_plane_state->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 ofdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
						     struct drm_atomic_state *state)
{
	struct drm_device *dev = plane->dev;
	struct ofdrm_device *odev = ofdrm_device_of_dev(dev);
	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_framebuffer *fb = plane_state->fb;
	unsigned int dst_pitch = odev->pitch;
	const struct drm_format_info *dst_format = odev->format;
	struct drm_atomic_helper_damage_iter iter;
	struct drm_rect damage;
	int ret, idx;

	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
	if (ret)
		return;

	if (!drm_dev_enter(dev, &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) {
		struct iosys_map dst = odev->screen_base;
		struct drm_rect dst_clip = plane_state->dst;

		if (!drm_rect_intersect(&dst_clip, &damage))
			continue;

		iosys_map_incr(&dst, drm_fb_clip_offset(dst_pitch, dst_format, &dst_clip));
		drm_fb_blit(&dst, &dst_pitch, dst_format->format, shadow_plane_state->data, 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 ofdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
						      struct drm_atomic_state *state)
{
	struct drm_device *dev = plane->dev;
	struct ofdrm_device *odev = ofdrm_device_of_dev(dev);
	struct iosys_map dst = odev->screen_base;
	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
	void __iomem *dst_vmap = dst.vaddr_iomem; /* TODO: Use mapping abstraction */
	unsigned int dst_pitch = odev->pitch;
	const struct drm_format_info *dst_format = odev->format;
	struct drm_rect dst_clip;
	unsigned long lines, linepixels, i;
	int idx;

	drm_rect_init(&dst_clip,
		      plane_state->src_x >> 16, plane_state->src_y >> 16,
		      plane_state->src_w >> 16, plane_state->src_h >> 16);

	lines = drm_rect_height(&dst_clip);
	linepixels = drm_rect_width(&dst_clip);

	if (!drm_dev_enter(dev, &idx))
		return;

	/* Clear buffer to black if disabled */
	dst_vmap += drm_fb_clip_offset(dst_pitch, dst_format, &dst_clip);
	for (i = 0; i < lines; ++i) {
		memset_io(dst_vmap, 0, linepixels * dst_format->cpp[0]);
		dst_vmap += dst_pitch;
	}

	drm_dev_exit(idx);
}

static const struct drm_plane_helper_funcs ofdrm_primary_plane_helper_funcs = {
	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
	.atomic_check = ofdrm_primary_plane_helper_atomic_check,
	.atomic_update = ofdrm_primary_plane_helper_atomic_update,
	.atomic_disable = ofdrm_primary_plane_helper_atomic_disable,
};

static const struct drm_plane_funcs ofdrm_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,
};

static enum drm_mode_status ofdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
							 const struct drm_display_mode *mode)
{
	struct ofdrm_device *odev = ofdrm_device_of_dev(crtc->dev);

	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &odev->mode);
}

static int ofdrm_crtc_helper_atomic_check(struct drm_crtc *crtc,
					  struct drm_atomic_state *new_state)
{
	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(new_state, crtc);

	if (!new_crtc_state->enable)
		return 0;

	return drm_atomic_helper_check_crtc_primary_plane(new_crtc_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 ofdrm_crtc_helper_funcs = {
	.mode_valid = ofdrm_crtc_helper_mode_valid,
	.atomic_check = ofdrm_crtc_helper_atomic_check,
};

static const struct drm_crtc_funcs ofdrm_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,
};

static int ofdrm_connector_helper_get_modes(struct drm_connector *connector)
{
	struct ofdrm_device *odev = ofdrm_device_of_dev(connector->dev);

	return drm_connector_helper_get_modes_fixed(connector, &odev->mode);
}

static const struct drm_connector_helper_funcs ofdrm_connector_helper_funcs = {
	.get_modes = ofdrm_connector_helper_get_modes,
};

static const struct drm_connector_funcs ofdrm_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 ofdrm_mode_config_funcs = {
	.fb_create = drm_gem_fb_create_with_dirty,
	.atomic_check = drm_atomic_helper_check,
	.atomic_commit = drm_atomic_helper_commit,
};

/*
 * Init / Cleanup
 */

static struct drm_display_mode ofdrm_mode(unsigned int width, unsigned int height)
{
	/*
	 * Assume a monitor resolution of 96 dpi to
	 * get a somewhat reasonable screen size.
	 */
	const struct drm_display_mode mode = {
		DRM_MODE_INIT(60, width, height,
			      DRM_MODE_RES_MM(width, 96ul),
			      DRM_MODE_RES_MM(height, 96ul))
	};

	return mode;
}

static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv,
						struct platform_device *pdev)
{
	struct device_node *of_node = pdev->dev.of_node;
	struct ofdrm_device *odev;
	struct drm_device *dev;
	int width, height, depth, linebytes;
	const struct drm_format_info *format;
	u64 address;
	resource_size_t fb_size, fb_base, fb_pgbase, fb_pgsize;
	struct resource *res, *mem;
	void __iomem *screen_base;
	struct drm_plane *primary_plane;
	struct drm_crtc *crtc;
	struct drm_encoder *encoder;
	struct drm_connector *connector;
	unsigned long max_width, max_height;
	size_t nformats;
	int ret;

	odev = devm_drm_dev_alloc(&pdev->dev, drv, struct ofdrm_device, dev);
	if (IS_ERR(odev))
		return ERR_CAST(odev);
	dev = &odev->dev;
	platform_set_drvdata(pdev, dev);

	ret = ofdrm_device_init_pci(odev);
	if (ret)
		return ERR_PTR(ret);

	/*
	 * OF display-node settings
	 */

	width = display_get_width_of(dev, of_node);
	if (width < 0)
		return ERR_PTR(width);
	height = display_get_height_of(dev, of_node);
	if (height < 0)
		return ERR_PTR(height);
	depth = display_get_depth_of(dev, of_node);
	if (depth < 0)
		return ERR_PTR(depth);
	linebytes = display_get_linebytes_of(dev, of_node);
	if (linebytes < 0)
		return ERR_PTR(linebytes);

	format = display_get_validated_format(dev, depth);
	if (IS_ERR(format))
		return ERR_CAST(format);
	if (!linebytes) {
		linebytes = drm_format_info_min_pitch(format, 0, width);
		if (drm_WARN_ON(dev, !linebytes))
			return ERR_PTR(-EINVAL);
	}

	fb_size = linebytes * height;

	/*
	 * Try to figure out the address of the framebuffer. Unfortunately, Open
	 * Firmware doesn't provide a standard way to do so. All we can do is a
	 * dodgy heuristic that happens to work in practice.
	 *
	 * On most machines, the "address" property contains what we need, though
	 * not on Matrox cards found in IBM machines. What appears to give good
	 * results is to go through the PCI ranges and pick one that encloses the
	 * "address" property. If none match, we pick the largest.
	 */
	address = display_get_address_of(dev, of_node);
	if (address != OF_BAD_ADDR) {
		struct resource fb_res = DEFINE_RES_MEM(address, fb_size);

		res = ofdrm_find_fb_resource(odev, &fb_res);
		if (!res)
			return ERR_PTR(-EINVAL);
		if (resource_contains(res, &fb_res))
			fb_base = address;
		else
			fb_base = res->start;
	} else {
		struct resource fb_res = DEFINE_RES_MEM(0u, fb_size);

		res = ofdrm_find_fb_resource(odev, &fb_res);
		if (!res)
			return ERR_PTR(-EINVAL);
		fb_base = res->start;
	}

	/*
	 * I/O resources
	 */

	fb_pgbase = round_down(fb_base, PAGE_SIZE);
	fb_pgsize = fb_base - fb_pgbase + round_up(fb_size, PAGE_SIZE);

	ret = devm_aperture_acquire_from_firmware(dev, fb_pgbase, fb_pgsize);
	if (ret) {
		drm_err(dev, "could not acquire memory range %pr: error %d\n", &res, ret);
		return ERR_PTR(ret);
	}

	mem = devm_request_mem_region(&pdev->dev, fb_pgbase, fb_pgsize, drv->name);
	if (!mem) {
		drm_warn(dev, "could not acquire memory region %pr\n", &res);
		return ERR_PTR(-ENOMEM);
	}

	screen_base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
	if (!screen_base)
		return ERR_PTR(-ENOMEM);

	/*
	 * Firmware framebuffer
	 */

	iosys_map_set_vaddr_iomem(&odev->screen_base, screen_base);
	odev->mode = ofdrm_mode(width, height);
	odev->format = format;
	odev->pitch = linebytes;

	drm_dbg(dev, "display mode={" DRM_MODE_FMT "}\n", DRM_MODE_ARG(&odev->mode));
	drm_dbg(dev, "framebuffer format=%p4cc, size=%dx%d, linebytes=%d byte\n",
		&format->format, width, height, linebytes);

	/*
	 * Mode-setting pipeline
	 */

	ret = drmm_mode_config_init(dev);
	if (ret)
		return ERR_PTR(ret);

	max_width = max_t(unsigned long, width, DRM_SHADOW_PLANE_MAX_WIDTH);
	max_height = max_t(unsigned long, height, DRM_SHADOW_PLANE_MAX_HEIGHT);

	dev->mode_config.min_width = width;
	dev->mode_config.max_width = max_width;
	dev->mode_config.min_height = height;
	dev->mode_config.max_height = max_height;
	dev->mode_config.funcs = &ofdrm_mode_config_funcs;
	switch (depth) {
	case 32:
		dev->mode_config.preferred_depth = 24;
		break;
	default:
		dev->mode_config.preferred_depth = depth;
		break;
	}

	/* Primary plane */

	nformats = drm_fb_build_fourcc_list(dev, &format->format, 1,
					    ofdrm_primary_plane_formats,
					    ARRAY_SIZE(ofdrm_primary_plane_formats),
					    odev->formats, ARRAY_SIZE(odev->formats));

	primary_plane = &odev->primary_plane;
	ret = drm_universal_plane_init(dev, primary_plane, 0, &ofdrm_primary_plane_funcs,
				       odev->formats, nformats,
				       ofdrm_primary_plane_format_modifiers,
				       DRM_PLANE_TYPE_PRIMARY, NULL);
	if (ret)
		return ERR_PTR(ret);
	drm_plane_helper_add(primary_plane, &ofdrm_primary_plane_helper_funcs);
	drm_plane_enable_fb_damage_clips(primary_plane);

	/* CRTC */

	crtc = &odev->crtc;
	ret = drm_crtc_init_with_planes(dev, crtc, primary_plane, NULL,
					&ofdrm_crtc_funcs, NULL);
	if (ret)
		return ERR_PTR(ret);
	drm_crtc_helper_add(crtc, &ofdrm_crtc_helper_funcs);

	/* Encoder */

	encoder = &odev->encoder;
	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
	if (ret)
		return ERR_PTR(ret);
	encoder->possible_crtcs = drm_crtc_mask(crtc);

	/* Connector */

	connector = &odev->connector;
	ret = drm_connector_init(dev, connector, &ofdrm_connector_funcs,
				 DRM_MODE_CONNECTOR_Unknown);
	if (ret)
		return ERR_PTR(ret);
	drm_connector_helper_add(connector, &ofdrm_connector_helper_funcs);
	drm_connector_set_panel_orientation_with_quirk(connector,
						       DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
						       width, height);

	ret = drm_connector_attach_encoder(connector, encoder);
	if (ret)
		return ERR_PTR(ret);

	drm_mode_config_reset(dev);

	return odev;
}

/*
 * DRM driver
 */

DEFINE_DRM_GEM_FOPS(ofdrm_fops);

static struct drm_driver ofdrm_driver = {
	DRM_GEM_SHMEM_DRIVER_OPS,
	.name			= DRIVER_NAME,
	.desc			= DRIVER_DESC,
	.date			= DRIVER_DATE,
	.major			= DRIVER_MAJOR,
	.minor			= DRIVER_MINOR,
	.driver_features	= DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
	.fops			= &ofdrm_fops,
};

/*
 * Platform driver
 */

static int ofdrm_probe(struct platform_device *pdev)
{
	struct ofdrm_device *odev;
	struct drm_device *dev;
	int ret;

	odev = ofdrm_device_create(&ofdrm_driver, pdev);
	if (IS_ERR(odev))
		return PTR_ERR(odev);
	dev = &odev->dev;

	ret = drm_dev_register(dev, 0);
	if (ret)
		return ret;

	/*
	 * FIXME: 24-bit color depth does not work reliably with a 32-bpp
	 * value. Force the bpp value of the scanout buffer's format.
	 */
	drm_fbdev_generic_setup(dev, drm_format_info_bpp(odev->format, 0));

	return 0;
}

static int ofdrm_remove(struct platform_device *pdev)
{
	struct drm_device *dev = platform_get_drvdata(pdev);

	drm_dev_unplug(dev);

	return 0;
}

static const struct of_device_id ofdrm_of_match_display[] = {
	{ .compatible = "display", },
	{ },
};
MODULE_DEVICE_TABLE(of, ofdrm_of_match_display);

static struct platform_driver ofdrm_platform_driver = {
	.driver = {
		.name = "of-display",
		.of_match_table = ofdrm_of_match_display,
	},
	.probe = ofdrm_probe,
	.remove = ofdrm_remove,
};

module_platform_driver(ofdrm_platform_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");