diff --git a/drivers/isdn/hisax/hfc4s8s_l1.c b/drivers/isdn/hisax/hfc4s8s_l1.c
index 1ac46c26b936..ba1d028343ec 100644
--- a/drivers/isdn/hisax/hfc4s8s_l1.c
+++ b/drivers/isdn/hisax/hfc4s8s_l1.c
@@ -29,6 +29,7 @@
 #include <linux/timer.h>
 #include <linux/skbuff.h>
 #include <linux/wait.h>
+#include <asm/io.h>
 #include "hisax_if.h"
 #include "hfc4s8s_l1.h"