Deprecating OBD-branch

This is a follow up to COVESA#635
Intention is to have them deprecated and remove them first in VSS 6.0
Until then anyone can create PRs with replacement signals as needed.
This PR contains replacement signals for diagnostics.

Signed-off-by: Erik Jaegervall <[email protected]>

CHANGELOG.md

@@ -197,4 +197,30 @@ A new version of vss-tools is used, with support for static IDs and jsconschema.
 
 ## Planned Changes VSS 5.0
 
--
+### OBD Branch deprecated
+
+The `Vehicle.OBD` branch is now deprecated. The plan is to remove it in VSS 6.0.
+The background is a decision that VSS standard catalog shall not contain a one-to-one representation of the OBD standard.
+Instead, VSS standard catalog may contain corresponding information elsewhere. As an example, instead of
+`Vehicle.OBD.EngineSpeed` (PID `0C`), the VSS signal `Vehicle.Powertrain.CombustionEngine.Speed` can be used.
+Note that not all signals in `Vehicle.OBD` has "duplicates", especially in the area of combustion engine control
+(like Oxygen sensor lambda and voltage readings) VSS currently does not have any counterparts in other parts of the tree.
+
+
+What to do if you as of today use signals from the OBD file
+
+* Check if any suitable replacement signal exist
+  Example: if you use `Vehicle.OBD.Speed`, consider using `Vehicle.Speed` instead
+* If not and the data may be of general interest; consider creating a pull request
+  with a replacement signal.
+  Example: VSS as of today only have Lambda information in OBD branch
+  If you need VSS signals for Lambda, consider creating new signals in
+  `Vehicle.Powertrain.CombustionEngine` branch.
+* If you really need the signals in this file and cannot replace them, then consider using the overlay file in the
+  `overlays` directory from VSS 6.0 onwards.
+
+## Planned Changes VSS 6.0
+
+### OBD Branch removed
+
+The `Vehicle.OBD` branch is now removed. If needed there is an OBD overlay in the `overlays` directory.

Makefile

@@ -45,6 +45,7 @@ ddsidl:
 overlays:
 	${TOOLSDIR}/vspec2json.py -I ./spec --uuid -u ./spec/units.yaml -o overlays/profiles/motorbike.vspec ./spec/VehicleSignalSpecification.vspec vss_rel_$$(cat VERSION)_motorbike.json
 	${TOOLSDIR}/vspec2json.py -I ./spec --uuid -u ./spec/units.yaml -o overlays/extensions/dual_wiper_systems.vspec ./spec/VehicleSignalSpecification.vspec vss_rel_$$(cat VERSION)_dualwiper.json
+	${TOOLSDIR}/vspec2json.py -I ./spec --uuid -u ./spec/units.yaml -o overlays/extensions/OBD.vspec ./spec/VehicleSignalSpecification.vspec vss_rel_$$(cat VERSION)_obd.json
 
 tests:
 	PYTHONPATH=${TOOLSDIR} pytest

overlays/extensions/OBD.vspec

@@ -0,0 +1,21 @@
+# Copyright (c) 2024 Contributors to COVESA
+#
+# This program and the accompanying materials are made available under the
+# terms of the Mozilla Public License 2.0 which is available at
+# https://www.mozilla.org/en-US/MPL/2.0/
+#
+# SPDX-License-Identifier: MPL-2.0
+
+# Overlay to support OBD signals
+# For VSS 5.0 this will be a duplicate of the Vehicle.OBD branch in the standard VSS catalog.
+# From VSS 6.0 onwards the Vehicle.OBD branch in the standard VSS catalog will be removed,
+# and then this overlay must be used if you want to use the VSS signals.
+
+Vehicle:
+  type: branch
+
+Vehicle.OBD:
+  type: branch
+  description: OBD data.
+
+#include OBD/OBD.vspec Vehicle.OBD