diff --git a/lib/bcd.c b/lib/bcd.c
index 40d304e..7e4750b 100644
--- a/lib/bcd.c
+++ b/lib/bcd.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/bcd.h>
 #include <linux/export.h>