diff --git a/drivers/input/serio/hp_sdc.c b/drivers/input/serio/hp_sdc.c
index 02b3ad8c0826..edfedd9a166c 100644
--- a/drivers/input/serio/hp_sdc.c
+++ b/drivers/input/serio/hp_sdc.c
@@ -69,6 +69,7 @@
 #include <linux/time.h>
 #include <linux/slab.h>
 #include <linux/hil.h>
+#include <linux/semaphore.h>
 #include <asm/io.h>
 #include <asm/system.h>