drm: Add drm_mode_create_rotation_property()

Add a function to create a standards compliant rotation property.

Signed-off-by: Ville Syrjälä <[e-mail]>
Reviewed-by: Imre Deak <[e-mail]>
Acked-by: Dave Airlie <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>

drivers/gpu/drm/drm_crtc.c

···
 	drm_modeset_lock_fini(&dev->mode_config.connection_mutex);
 }
 EXPORT_SYMBOL(drm_mode_config_cleanup);
+
+struct drm_property *drm_mode_create_rotation_property(struct drm_device *dev,
+						       unsigned int supported_rotations)
+{
+	static const struct drm_prop_enum_list props[] = {
+		{ DRM_ROTATE_0,   "rotate-0" },
+		{ DRM_ROTATE_90,  "rotate-90" },
+		{ DRM_ROTATE_180, "rotate-180" },
+		{ DRM_ROTATE_270, "rotate-270" },
+		{ DRM_REFLECT_X,  "reflect-x" },
+		{ DRM_REFLECT_Y,  "reflect-y" },
+	};
+
+	return drm_property_create_bitmask(dev, 0, "rotation",
+					   props, ARRAY_SIZE(props),
+					   supported_rotations);
+}
+EXPORT_SYMBOL(drm_mode_create_rotation_property);

include/drm/drm_crtc.h

···
 extern int drm_format_horz_chroma_subsampling(uint32_t format);
 extern int drm_format_vert_chroma_subsampling(uint32_t format);
 extern const char *drm_get_format_name(uint32_t format);
+extern struct drm_property *drm_mode_create_rotation_property(struct drm_device *dev,
+							      unsigned int supported_rotations);
 
 /* Helpers */