diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index 780198c..2629eb7 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -1,5 +1,5 @@
-/* Osmocom Generic Subscriber Update Protocol message encoder/decoder */
-
+/*! \file gsup.c
+ * Osmocom Generic Subscriber Update Protocol message encoder/decoder. */
 /*
  * (C) 2014 by sysmocom s.f.m.c. GmbH
  * (C) 2015 by Holger Hans Peter Freyther