diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 939596d..94cd813 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef S390_CIO_H
 #define S390_CIO_H