diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
index 68bb305..d5ecea3 100644
--- a/drivers/acpi/debugfs.c
+++ b/drivers/acpi/debugfs.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * debugfs.c - ACPI debugfs interface to userspace.
  */