Re: [PATCH v3 1/3] dt-bindings: Convert graph bindings to json-schema

Rob Herring
2020-11-12T01:45:16Z

On Wed, Nov 11, 2020 at 8:27 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Rob,
>
> On Wed, Nov 11, 2020 at 08:25:40AM -0600, Rob Herring wrote:
> > On Wed, Nov 11, 2020 at 8:00 AM Laurent Pinchart wrote:
> > > On Mon, Nov 02, 2020 at 02:36:54PM -0600, Rob Herring wrote:
> > > > From: Sameer Pujar <spujar@nvidia.com>
> > > >
> > > > Convert device tree bindings of graph to YAML format. Currently graph.txt
> > > > doc is referenced in multiple files and all of these need to use schema
> > > > references. For now graph.txt is updated to refer to graph.yaml.
> > > >
> > > > For users of the graph binding, they should reference to the graph
> > > > schema from either 'ports' or 'port' property:
> > > >
> > > > properties:
> > > > ports:
> > > > type: object
> > > > $ref: graph.yaml#/properties/ports
> > > >
> > > > properties:
> > > > port@0:
> > > > description: What data this port has
> > > >
> > > > ...
> > > >
> > > > Or:
> > > >
> > > > properties:
> > > > port:
> > > > description: What data this port has
> > > > type: object
> > > > $ref: graph.yaml#/properties/port
> > >
> > > Sounds like a good approach.
> > >
> > > > Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> > > > Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
> > > > Signed-off-by: Rob Herring <robh@kernel.org>
> > > > ---
> > > > v3:
> > > > - Move port 'reg' to port@* and make required
> > > > - Make remote-endpoint required
> > > > - Add 'additionalProperties: true' now required
> > > > - Fix yamllint warnings
> > > >
> > > > Documentation/devicetree/bindings/graph.txt | 129 +-----------
> > > > Documentation/devicetree/bindings/graph.yaml | 199 +++++++++++++++++++
> > > > 2 files changed, 200 insertions(+), 128 deletions(-)
> > > > create mode 100644 Documentation/devicetree/bindings/graph.yaml
> >
> > [...]
> >
> > > > diff --git a/Documentation/devicetree/bindings/graph.yaml b/Documentation/devicetree/bindings/graph.yaml
> > > > new file mode 100644
> > > > index 000000000000..b56720c5a13e
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/graph.yaml
> > > > @@ -0,0 +1,199 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/graph.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Common bindings for device graphs
> > > > +
> > > > +description: |
> > > > + The hierarchical organisation of the device tree is well suited to describe
> > > > + control flow to devices, but there can be more complex connections between
> > > > + devices that work together to form a logical compound device, following an
> > > > + arbitrarily complex graph.
> > > > + There already is a simple directed graph between devices tree nodes using
> > > > + phandle properties pointing to other nodes to describe connections that
> > > > + can not be inferred from device tree parent-child relationships. The device
> > > > + tree graph bindings described herein abstract more complex devices that can
> > > > + have multiple specifiable ports, each of which can be linked to one or more
> > > > + ports of other devices.
> > > > +
> > > > + These common bindings do not contain any information about the direction or
> > > > + type of the connections, they just map their existence. Specific properties
> > > > + may be described by specialized bindings depending on the type of connection.
> > > > +
> > > > + To see how this binding applies to video pipelines, for example, see
> > > > + Documentation/devicetree/bindings/media/video-interfaces.txt.
> > > > + Here the ports describe data interfaces, and the links between them are
> > > > + the connecting data buses. A single port with multiple connections can
> > > > + correspond to multiple devices being connected to the same physical bus.
> > > > +
> > > > +maintainers:
> > > > + - Philipp Zabel <p.zabel@pengutronix.de>
> > > > +
> > > > +select: false
> > > > +
> > > > +properties:
> > > > + port:
> > > > + type: object
> > > > + description:
> > > > + If there is more than one endpoint node or 'reg' property present in
> > > > + endpoint nodes then '#address-cells' and '#size-cells' properties are
> > > > + required.
> > > > +
> > > > + properties:
> > > > + "#address-cells":
> > > > + const: 1
> > > > +
> > > > + "#size-cells":
> > > > + const: 0
> > > > +
> > > > + patternProperties:
> > > > + "^endpoint(@[0-9a-f]+)?$":
> > > > + type: object
> > > > + properties:
> > > > + reg:
> > > > + maxItems: 1
> > > > +
> > > > + remote-endpoint:
> > > > + description: |
> > > > + phandle to an 'endpoint' subnode of a remote device node.
> > > > + $ref: /schemas/types.yaml#/definitions/phandle
> > > > +
> > > > + required:
> > > > + - remote-endpoint
> > >
> > > As noted elsewhere, this shouldn't be required.
> > >
> > > Should we set additionalProperties: false here ?
> >
> > No, we've got a bunch of properties that get added to endpoint nodes.
> > There's a few cases where 'port' nodes have properties too.
>
> I meant the port node, which I wasn't aware needed additional
> properties. Do you have any example ? (I wonder if you will point me to
> bindings that I have written ;-))

Not you, but Renesas. dual-lvds-{odd,even}-pixels was the only one I
think. But really, I think we could actually drop those if the port
numbering defines even/odd instead. There's a patch I just reviewed
for common dual lane panels. See
1604993797-14240-1-git-send-email-victor.liu@nxp.com

Rob