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

Rob Herring
2020-11-11T14:00:16Z

On Wed, Nov 11, 2020 at 3:52 AM Sameer Pujar <spujar@nvidia.com> wrote:
>
> Hi Rob,
>
> > 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
> > $ref: graph.yaml#/properties/port
> >
> > Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> > Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
> > Signed-off-by: Rob Herring <robh@kernel.org>
> > ---
> > v3:
> > - Move port 'reg' to port@* and make required
> > - Make remote-endpoint required
> > - Add 'additionalProperties: true' now required
> > - Fix yamllint warnings
> >
> > Documentation/devicetree/bindings/graph.txt | 129 +-----------
> > Documentation/devicetree/bindings/graph.yaml | 199 +++++++++++++++++++
> > 2 files changed, 200 insertions(+), 128 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/graph.yaml
> >
> ...
> > diff --git a/Documentation/devicetree/bindings/graph.yaml b/Documentation/devicetree/bindings/graph.yaml
> > new file mode 100644
> > index 000000000000..b56720c5a13e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/graph.yaml
> > @@ -0,0 +1,199 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$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
>
> Does 'remote-endpoint' have to be a required property?
> In case of pluggable modules, the remote-endpoint may not be available
> unless the module is plugged in. In other words, device-2 in below
> example may not always be available, but still device-1 endpoint
> configuration and usage may be required?

No, I've dropped it. I noticed the same thing converting some of the
schema over to use this.

Rob