drm: Export drm_plane_has_format()

Export drm_plane_has_format() so that drivers can use it.

v2: add kerneldoc

Reviewed-by: Jani Nikula <[e-mail]>
Reviewed-by: Daniel Vetter <[e-mail]>
Signed-off-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Daniel Vetter <[e-mail]>
Acked-by: Daniel Stone <[e-mail]>
Acked-by: Thomas Zimmermann <[e-mail]>

drivers/gpu/drm/drm_crtc_internal.h

···
 /* drm_plane.c */
 int drm_plane_register_all(struct drm_device *dev);
 void drm_plane_unregister_all(struct drm_device *dev);
-bool drm_plane_has_format(struct drm_plane *plane,
-			  u32 format, u64 modifier);
 struct drm_mode_rect *
 __drm_plane_get_damage_clips(const struct drm_plane_state *state);
 

drivers/gpu/drm/drm_plane.c

···
 	return 0;
 }
 
+/**
+ * drm_plane_has_format - Check whether the plane supports this format and modifier combination
+ * @plane: drm plane
+ * @format: pixel format (DRM_FORMAT_*)
+ * @modifier: data layout modifier
+ *
+ * Returns:
+ * Whether the plane supports the specified format and modifier combination.
+ */
 bool drm_plane_has_format(struct drm_plane *plane,
 			  u32 format, u64 modifier)
 {
···
 
 	return true;
 }
+EXPORT_SYMBOL(drm_plane_has_format);
 
 static int __setplane_check(struct drm_plane *plane,
 			    struct drm_crtc *crtc,

include/drm/drm_plane.h

···
 #define drm_for_each_plane(plane, dev) \
 	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head)
 
+bool drm_plane_has_format(struct drm_plane *plane,
+			  u32 format, u64 modifier);
 bool drm_any_plane_has_format(struct drm_device *dev,
 			      u32 format, u64 modifier);