new_encoder = drm_atomic_helper_best_encoder(connector);
 
                if (new_encoder) {
-                       if (encoder_mask & (1 << drm_encoder_index(new_encoder))) {
+                       if (encoder_mask & drm_encoder_mask(new_encoder)) {
                                DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] on [CONNECTOR:%d:%s] already assigned\n",
                                        new_encoder->base.id, new_encoder->name,
                                        connector->base.id, connector->name);
                                return -EINVAL;
                        }
 
-                       encoder_mask |= 1 << drm_encoder_index(new_encoder);
+                       encoder_mask |= drm_encoder_mask(new_encoder);
                }
        }
 
                        continue;
 
                encoder = connector->state->best_encoder;
-               if (!encoder || !(encoder_mask & (1 << drm_encoder_index(encoder))))
+               if (!encoder || !(encoder_mask & drm_encoder_mask(encoder)))
                        continue;
 
                if (!disable_conflicting_encoders) {
                        crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
                        crtc_state->encoder_mask &=
-                               ~(1 << drm_encoder_index(conn_state->best_encoder));
+                               ~drm_encoder_mask(conn_state->best_encoder);
                }
        }
 
                        crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
                        crtc_state->encoder_mask |=
-                               1 << drm_encoder_index(encoder);
+                               drm_encoder_mask(encoder);
                }
        }
 
 
  * Given a registered encoder, return the index of that encoder within a DRM
  * device's list of encoders.
  */
-static inline unsigned int drm_encoder_index(struct drm_encoder *encoder)
+static inline unsigned int drm_encoder_index(const struct drm_encoder *encoder)
 {
        return encoder->index;
 }
 
+/**
+ * drm_encoder_mask - find the mask of a registered ENCODER
+ * @encoder: encoder to find mask for
+ *
+ * Given a registered encoder, return the mask bit of that encoder for an
+ * encoder's possible_clones field.
+ */
+static inline u32 drm_encoder_mask(const struct drm_encoder *encoder)
+{
+       return 1 << drm_encoder_index(encoder);
+}
+
 /**
  * drm_encoder_crtc_ok - can a given crtc drive a given encoder?
  * @encoder: encoder to test
  */
 #define drm_for_each_encoder_mask(encoder, dev, encoder_mask) \
        list_for_each_entry((encoder), &(dev)->mode_config.encoder_list, head) \
-               for_each_if ((encoder_mask) & (1 << drm_encoder_index(encoder)))
+               for_each_if ((encoder_mask) & drm_encoder_mask(encoder))
 
 /**
  * drm_for_each_encoder - iterate over all encoders