drm/mediatek: Add DRM_MODE_ROTATE_0 to rotation property

Always add DRM_MODE_ROTATE_0 to rotation property to meet
IGT's (Intel GPU Tools) requirement.

Reviewed-by: CK Hu <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Hsiao Chien Sung <[e-mail]>
Link: https://patchwork.kernel.org/project/dri-devel/patch/[e-mail]/
Signed-off-by: Chun-Kuang Hu <[e-mail]>

drivers/gpu/drm/mediatek/mtk_ddp_comp.h

···
 	if (comp->funcs && comp->funcs->supported_rotations)
 		return comp->funcs->supported_rotations(comp->dev);
 
-	return 0;
+	/*
+	 * In order to pass IGT tests, DRM_MODE_ROTATE_0 is required when
+	 * rotation is not supported.
+	 */
+	return DRM_MODE_ROTATE_0;
 }
 
 static inline unsigned int mtk_ddp_comp_layer_nr(struct mtk_ddp_comp *comp)

drivers/gpu/drm/mediatek/mtk_disp_ovl.c

···
 			struct mtk_plane_state *mtk_state)
 {
 	struct drm_plane_state *state = &mtk_state->base;
-	unsigned int rotation = 0;
 
-	rotation = drm_rotation_simplify(state->rotation,
-					 DRM_MODE_ROTATE_0 |
-					 DRM_MODE_REFLECT_X |
-					 DRM_MODE_REFLECT_Y);
-	rotation &= ~DRM_MODE_ROTATE_0;
-
-	/* We can only do reflection, not rotation */
-	if ((rotation & DRM_MODE_ROTATE_MASK) != 0)
+	/* check if any unsupported rotation is set */
+	if (state->rotation & ~mtk_ovl_supported_rotations(dev))
 		return -EINVAL;
 
 	/*
 	 * TODO: Rotating/reflecting YUV buffers is not supported at this time.
 	 *	 Only RGB[AX] variants are supported.
+	 *	 Since DRM_MODE_ROTATE_0 means "no rotation", we should not
+	 *	 reject layers with this property.
 	 */
-	if (state->fb->format->is_yuv && rotation != 0)
+	if (state->fb->format->is_yuv && (state->rotation & ~DRM_MODE_ROTATE_0))
 		return -EINVAL;
-
-	state->rotation = rotation;
 
 	return 0;
 }

drivers/gpu/drm/mediatek/mtk_plane.c

···
 		return err;
 	}
 
-	if (supported_rotations & ~DRM_MODE_ROTATE_0) {
+	if (supported_rotations) {
 		err = drm_plane_create_rotation_property(plane,
 							 DRM_MODE_ROTATE_0,
 							 supported_rotations);