diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 2133f37..d5e4e63 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -21,6 +21,7 @@
 
 #include <mach/board.h>
 #include <mach/at91_rtt.h>
+#include <mach/cpu.h>
 
 
 /*