/*
         * Some devices don't support bulk write, for
-        * them we have a series of single write operations.
+        * them we have a series of single write operations in the first two if
+        * blocks.
+        *
+        * The first if block is used for memory mapped io. It does not allow
+        * val_bytes of 3 for example.
+        * The second one is used for busses which do not have this limitation
+        * and can write arbitrary value lengths.
         */
-       if (!map->bus || map->use_single_rw) {
+       if (!map->bus) {
                map->lock(map->lock_arg);
                for (i = 0; i < val_count; i++) {
                        unsigned int ival;
                }
 out:
                map->unlock(map->lock_arg);
+       } else if (map->use_single_rw) {
+               map->lock(map->lock_arg);
+               for (i = 0; i < val_count; i++) {
+                       ret = _regmap_raw_write(map,
+                                               reg + (i * map->reg_stride),
+                                               val + (i * val_bytes),
+                                               val_bytes);
+                       if (ret)
+                               break;
+               }
+               map->unlock(map->lock_arg);
        } else {
                void *wval;