diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index e178ac27e73c6de46ef48c2d94464cd64b4ca011..fd5a5e85d7dc604e2ebe237ee34ce9355d81d866 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -52,6 +52,7 @@
 #include <linux/dmi.h>
 #include <linux/kthread.h>
 #include <linux/acpi.h>
+#include <linux/ctype.h>
 
 #define PFX "ipmi_ssif: "
 #define DEVICE_NAME "ipmi_ssif"