diff --git a/common/hw-gfx-dp_aux_ch.ads b/common/hw-gfx-dp_aux_ch.ads
new file mode 100644
index 0000000..c65f860
--- /dev/null
+++ b/common/hw-gfx-dp_aux_ch.ads
@@ -0,0 +1,54 @@
+--
+-- Copyright (C) 2015-2016 secunet Security Networks AG
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; version 2 of the License.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+
+with HW.GFX.I2C;
+with HW.GFX.DP_Defs;
+
+private generic
+
+   type T (<>) is limited private;
+
+   with procedure Aux_Request
+     (Port              : in     T;
+      Request           : in     DP_Defs.Aux_Request;
+      Request_Length    : in     DP_Defs.Aux_Request_Length;
+      Response          :    out DP_Defs.Aux_Response;
+      Response_Length   :    out DP_Defs.Aux_Response_Length;
+      Success           :    out Boolean);
+
+package HW.GFX.DP_Aux_Ch is
+
+   procedure Aux_Read
+     (Port     : in     T;
+      Address  : in     DP_Defs.Aux_Message_Address;
+      Length   : in out DP_Defs.Aux_Payload_Length;
+      Data     :    out DP_Defs.Aux_Payload;
+      Success  :    out Boolean);
+
+   procedure Aux_Write
+     (Port     : in     T;
+      Address  : in     DP_Defs.Aux_Message_Address;
+      Length   : in     DP_Defs.Aux_Payload_Length;
+      Data     : in     DP_Defs.Aux_Payload;
+      Success  :    out Boolean);
+
+   ----------------------------------------------------------------------------
+
+   procedure I2C_Read
+     (Port     : in     T;
+      Address  : in     I2C.Transfer_Address;
+      Length   : in out I2C.Transfer_Length;
+      Data     :    out I2C.Transfer_Data;
+      Success  :    out Boolean);
+
+end HW.GFX.DP_Aux_Ch;