int framedur_ns, linedur_ns, pixeldur_ns;
 
        /* if you are using the helper */
-       void *helper_private;
+       const void *helper_private;
 
        struct drm_object_properties properties;
 
        struct drm_crtc *crtc;
        struct drm_bridge *bridge;
        const struct drm_encoder_funcs *funcs;
-       void *helper_private;
+       const void *helper_private;
 };
 
 /* should we poll this connector for connects and disconnects */
        /* requested DPMS state */
        int dpms;
 
-       void *helper_private;
+       const void *helper_private;
 
        /* forced on connector */
        struct drm_cmdline_mode cmdline_mode;
 
        enum drm_plane_type type;
 
-       void *helper_private;
+       const void *helper_private;
 
        struct drm_plane_state *state;
 };
 
 static inline void drm_crtc_helper_add(struct drm_crtc *crtc,
                                       const struct drm_crtc_helper_funcs *funcs)
 {
-       crtc->helper_private = (void *)funcs;
+       crtc->helper_private = funcs;
 }
 
 static inline void drm_encoder_helper_add(struct drm_encoder *encoder,
                                          const struct drm_encoder_helper_funcs *funcs)
 {
-       encoder->helper_private = (void *)funcs;
+       encoder->helper_private = funcs;
 }
 
 static inline void drm_connector_helper_add(struct drm_connector *connector,
                                            const struct drm_connector_helper_funcs *funcs)
 {
-       connector->helper_private = (void *)funcs;
+       connector->helper_private = funcs;
 }
 
 extern void drm_helper_resume_force_mode(struct drm_device *dev);
 
 static inline void drm_plane_helper_add(struct drm_plane *plane,
                                        const struct drm_plane_helper_funcs *funcs)
 {
-       plane->helper_private = (void *)funcs;
+       plane->helper_private = funcs;
 }
 
 extern int drm_plane_helper_check_update(struct drm_plane *plane,