diff --git a/drivers/staging/cx25821/cx25821.h b/drivers/staging/cx25821/cx25821.h
index 074ea34..578cdd5 100644
--- a/drivers/staging/cx25821/cx25821.h
+++ b/drivers/staging/cx25821/cx25821.h
@@ -32,6 +32,7 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/kdev_t.h>
+#include <linux/smp_lock.h>
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-device.h>