diff --git a/serial.c b/serial.c
index d59bf44..808c215 100644
--- a/serial.c
+++ b/serial.c
@@ -322,6 +322,7 @@
 		const void *buf, size_t len)
 {
 	mctp_rx_consume(serial, buf, len);
+	return 0;
 }
 
 static int mctp_serial_core_start(struct mctp_binding *binding)