diff --git a/include/linux/jz4740-adc.h b/include/linux/jz4740-adc.h
index 8184578..19d995c 100644
--- a/include/linux/jz4740-adc.h
+++ b/include/linux/jz4740-adc.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #ifndef __LINUX_JZ4740_ADC
 #define __LINUX_JZ4740_ADC