diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index da017dc..53358ac 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -170,7 +170,7 @@
  * serial port to the serial core. That serial port is then used as a
  * default output.
  */
-void serial_initialize(void)
+int serial_initialize(void)
 {
 	atmel_serial_initialize();
 	mcf_serial_initialize();
@@ -183,6 +183,8 @@
 	mtk_serial_initialize();
 
 	serial_assign(default_serial_console()->name);
+
+	return 0;
 }
 
 static int serial_stub_start(struct stdio_dev *sdev)