diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index f46e247912cbe76b81b1181e80ba8c5e687b9c14..744ed145bfa48efd833f6da863d556ecc3ef1226 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -273,7 +273,9 @@ EXPORT_SYMBOL_GPL(regcache_sync);
  */
 void regcache_cache_only(struct regmap *map, bool enable)
 {
+	mutex_lock(&map->sync_lock);
 	map->cache_only = enable;
+	mutex_unlock(&map->sync_lock);
 }
 EXPORT_SYMBOL_GPL(regcache_cache_only);