diff --git a/drivers/tty/serial/nwpserial.c b/drivers/tty/serial/nwpserial.c
index c06366b6bc29f461f324f8494c0cdfb45032c876..5da7622e88c30bc86cc7f31693685fa0fface92b 100644
--- a/drivers/tty/serial/nwpserial.c
+++ b/drivers/tty/serial/nwpserial.c
@@ -22,6 +22,7 @@
 #include <linux/of_platform.h>
 #include <linux/of_device.h>
 #include <linux/nwpserial.h>
+#include <linux/delay.h>
 #include <asm/prom.h>
 #include <asm/dcr.h>