diff --git a/net/cdp.h b/net/cdp.h
index ec7315a..95e4ce0 100644
--- a/net/cdp.h
+++ b/net/cdp.h
@@ -6,6 +6,7 @@
  *	Copyright 2000 Roland Borde
  *	Copyright 2000 Paolo Scaffardi
  *	Copyright 2000-2002 Wolfgang Denk, wd@denx.de
+ *	SPDX-License-Identifier:	GPL-2.0
  */
 
 #if defined(CONFIG_CMD_CDP)