diff --git a/plugins/provider/mm/calls-mm-origin.c b/plugins/provider/mm/calls-mm-origin.c
index 319b57f..4bda1d4 100644
--- a/plugins/provider/mm/calls-mm-origin.c
+++ b/plugins/provider/mm/calls-mm-origin.c
@@ -191,7 +191,7 @@ calls_mm_ussd_get_state (CallsUssd *ussd)
   if (!self->ussd)
     return CALLS_USSD_STATE_UNKNOWN;
 
-  return mm_modem_3gpp_ussd_get_state (self->ussd);
+  return (CallsUssdState) mm_modem_3gpp_ussd_get_state (self->ussd);
 }
 
 static void
diff --git a/src/calls-ussd.h b/src/calls-ussd.h
index 498ee34..3fb962e 100644
--- a/src/calls-ussd.h
+++ b/src/calls-ussd.h
@@ -32,6 +32,7 @@ G_BEGIN_DECLS
 
 G_DECLARE_INTERFACE (CallsUssd, calls_ussd, CALLS, USSD, GObject)
 
+/* This is basically MMModem3gppUssdSessionState */
 typedef enum
 {
   CALLS_USSD_STATE_UNKNOWN,