diff --git a/include/linux/net_tstamp.h b/include/linux/net_tstamp.h
index 3799c79b6c83..662074b08c94 100644
--- a/include/linux/net_tstamp.h
+++ b/include/linux/net_tstamp.h
@@ -14,6 +14,7 @@
 					 SOF_TIMESTAMPING_RAW_HARDWARE)
 
 enum hwtstamp_source {
+	HWTSTAMP_SOURCE_UNSPEC,
 	HWTSTAMP_SOURCE_NETDEV,
 	HWTSTAMP_SOURCE_PHYLIB,
 };