void (*stop)(struct mtk_ddp_comp *comp);
        void (*enable_vblank)(struct mtk_ddp_comp *comp, struct drm_crtc *crtc);
        void (*disable_vblank)(struct mtk_ddp_comp *comp);
+       unsigned int (*layer_nr)(struct mtk_ddp_comp *comp);
        void (*layer_on)(struct mtk_ddp_comp *comp, unsigned int idx);
        void (*layer_off)(struct mtk_ddp_comp *comp, unsigned int idx);
        void (*layer_config)(struct mtk_ddp_comp *comp, unsigned int idx,
                comp->funcs->disable_vblank(comp);
 }
 
+static inline unsigned int mtk_ddp_comp_layer_nr(struct mtk_ddp_comp *comp)
+{
+       if (comp->funcs && comp->funcs->layer_nr)
+               return comp->funcs->layer_nr(comp);
+
+       return 0;
+}
+
 static inline void mtk_ddp_comp_layer_on(struct mtk_ddp_comp *comp,
                                         unsigned int idx)
 {