diff --git a/tools/usb/Makefile b/tools/usb/Makefile
index acf2165..4e65060 100644
--- a/tools/usb/Makefile
+++ b/tools/usb/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 # Makefile for USB tools
 
 CC = $(CROSS_COMPILE)gcc