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

Message ID 20201102203656.220187-2-robh@kernel.org
State Changes Requested
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Series dt-bindings: Convert graph bindings to json-schema | expand

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Commit Message

Rob Herring Nov. 2, 2020, 8:36 p.m. UTC
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

--
2.25.1

Comments

Sam Ravnborg Nov. 5, 2020, 9:43 p.m. UTC | #1
Hi Rob/Sameer


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
Please fix so this example is correct - append /schemas/

> 
>     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
Likewise.

Otherwise I could be confused when looking it up later.

> 
> Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
> Signed-off-by: Rob Herring <robh@kernel.org>

With the changelog fixed:
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Sameer Pujar Nov. 11, 2020, 9:51 a.m. UTC | #2
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?

...

> +  # Links between endpoints:
> +  #
> +  # Each endpoint should contain a 'remote-endpoint' phandle property that
> +  # points to the corresponding endpoint in the port of the remote device.
> +  # In turn, the remote endpoint should contain a 'remote-endpoint' property.
> +  # If it has one, it must not point to anything other than the local endpoint.
> +  # Two endpoints with their 'remote-endpoint' phandles pointing at each other
> +  # form a link between the containing ports.
> +  - |
> +    device-1 {
> +        port {
> +            device_1_output: endpoint {
> +                remote-endpoint = <&device_2_input>;
> +            };
> +        };
> +    };
> +
> +    device-2 {
> +        port {
> +            device_2_input: endpoint {
> +                remote-endpoint = <&device_1_output>;
> +            };
> +        };
> +    };
> +
> +...
> --
> 2.25.1
Rob Herring Nov. 11, 2020, 1:35 p.m. UTC | #3
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
Laurent Pinchart Nov. 11, 2020, 2 p.m. UTC | #4
Hi Rob and Sameer,

Thank you for the patch.

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.txt b/Documentation/devicetree/bindings/graph.txt
> index 0415e2c53ba0..b7818d61cef7 100644
> --- a/Documentation/devicetree/bindings/graph.txt
> +++ b/Documentation/devicetree/bindings/graph.txt
> @@ -1,128 +1 @@
> -Common bindings for device graphs
> -
> -General concept
> ----------------
> -
> -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.
> -
> -Organisation of ports and endpoints
> ------------------------------------
> -
> -Ports are described by child 'port' nodes contained in the device node.
> -Each port node contains an 'endpoint' subnode for each remote device port
> -connected to this port. If a single port is connected to more than one
> -remote device, an 'endpoint' child node must be provided for each link.
> -If more than one port is present in a device node or there is more than one
> -endpoint at a port, or a port node needs to be associated with a selected
> -hardware interface, a common scheme using '#address-cells', '#size-cells'
> -and 'reg' properties is used to number the nodes.
> -
> -device {
> -        ...
> -        #address-cells = <1>;
> -        #size-cells = <0>;
> -
> -        port@0 {
> -	        #address-cells = <1>;
> -	        #size-cells = <0>;
> -		reg = <0>;
> -
> -                endpoint@0 {
> -			reg = <0>;
> -			...
> -		};
> -                endpoint@1 {
> -			reg = <1>;
> -			...
> -		};
> -        };
> -
> -        port@1 {
> -		reg = <1>;
> -
> -		endpoint { ... };
> -	};
> -};
> -
> -All 'port' nodes can be grouped under an optional 'ports' node, which
> -allows to specify #address-cells, #size-cells properties for the 'port'
> -nodes independently from any other child device nodes a device might
> -have.
> -
> -device {
> -        ...
> -        ports {
> -                #address-cells = <1>;
> -                #size-cells = <0>;
> -
> -                port@0 {
> -                        ...
> -                        endpoint@0 { ... };
> -                        endpoint@1 { ... };
> -                };
> -
> -                port@1 { ... };
> -        };
> -};
> -
> -Links between endpoints
> ------------------------
> -
> -Each endpoint should contain a 'remote-endpoint' phandle property that points
> -to the corresponding endpoint in the port of the remote device. In turn, the
> -remote endpoint should contain a 'remote-endpoint' property. If it has one, it
> -must not point to anything other than the local endpoint. Two endpoints with
> -their 'remote-endpoint' phandles pointing at each other form a link between the
> -containing ports.
> -
> -device-1 {
> -        port {
> -                device_1_output: endpoint {
> -                        remote-endpoint = <&device_2_input>;
> -                };
> -        };
> -};
> -
> -device-2 {
> -        port {
> -                device_2_input: endpoint {
> -                        remote-endpoint = <&device_1_output>;
> -                };
> -        };
> -};
> -
> -Required properties
> --------------------
> -
> -If there is more than one 'port' or more than one 'endpoint' node or 'reg'
> -property present in the port and/or endpoint nodes then the following
> -properties are required in a relevant parent node:
> -
> - - #address-cells : number of cells required to define port/endpoint
> -                    identifier, should be 1.
> - - #size-cells    : should be zero.
> -
> -Optional endpoint properties
> -----------------------------
> -
> -- remote-endpoint: phandle to an 'endpoint' subnode of a remote device node.
> -
> +This file has moved to 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 ?

> +
> +  ports:
> +    type: object
> +    description: |
> +      If there is more than one port node or 'reg' property present in port
> +      nodes then '#address-cells' and '#size-cells' properties are required.
> +      In such cases all port nodes can be grouped under 'ports' independently
> +      from any other child device nodes a device might have.

Allowing multiple port nodes not grouped in a ports node has created
complexity, with very little gain. Should we forbid that going forward ?

> +
> +    properties:
> +      "#address-cells":
> +        const: 1
> +
> +      "#size-cells":
> +        const: 0
> +
> +    patternProperties:
> +      "^port(@[0-9a-f]+)?$":
> +        $ref: "#/properties/port"
> +        type: object
> +
> +        properties:
> +          reg:
> +            maxItems: 1
> +
> +        required:
> +          - reg
> +
> +

Maybe a single blank line ?

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +    additionalProperties: false
> +
> +additionalProperties: true
> +
> +examples:
> +  # Organisation of ports and endpoints:
> +  #
> +  # Ports are described by child 'port' nodes contained in the device node.
> +  # Each port node contains an 'endpoint' subnode for each remote device port
> +  # connected to this port. If a single port is connected to more than one
> +  # remote device, an 'endpoint' child node must be provided for each link.
> +  # If more than one port is present in a device node or there is more than
> +  # one endpoint at a port, or a port node needs to be associated with a
> +  # selected hardware interface, a common scheme using '#address-cells',
> +  # '#size-cells' and 'reg' properties is used to number the nodes.
> +  - |
> +    device {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        port@0 {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            reg = <0>;
> +
> +            endpoint@0 {
> +                reg = <0>;
> +                // ...
> +            };
> +            endpoint@1 {
> +                reg = <1>;
> +                // ...
> +            };
> +        };
> +
> +        port@1 {
> +            reg = <1>;
> +
> +            endpoint {
> +                // ...
> +            };
> +        };
> +    };
> +
> +  # All 'port' nodes can be grouped under an optional 'ports' node, which
> +  # allows to specify #address-cells, #size-cells properties for the 'port'
> +  # nodes independently from any other child device nodes a device might
> +  # have.
> +  - |
> +    device {
> +        // ...
> +        ports {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            port@0 {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                reg = <0>;
> +                // ...
> +
> +                endpoint@0 {
> +                    reg = <0>;
> +                    // ...
> +                };
> +                endpoint@1 {
> +                    reg = <1>;
> +                    // ...
> +                };
> +            };
> +
> +            port@1 {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                reg = <1>;
> +                // ...
> +            };
> +        };
> +    };
> +
> +  # Links between endpoints:
> +  #
> +  # Each endpoint should contain a 'remote-endpoint' phandle property that
> +  # points to the corresponding endpoint in the port of the remote device.
> +  # In turn, the remote endpoint should contain a 'remote-endpoint' property.
> +  # If it has one, it must not point to anything other than the local endpoint.
> +  # Two endpoints with their 'remote-endpoint' phandles pointing at each other
> +  # form a link between the containing ports.
> +  - |
> +    device-1 {
> +        port {
> +            device_1_output: endpoint {
> +                remote-endpoint = <&device_2_input>;
> +            };
> +        };
> +    };
> +
> +    device-2 {
> +        port {
> +            device_2_input: endpoint {
> +                remote-endpoint = <&device_1_output>;
> +            };
> +        };
> +    };
> +
> +...
Rob Herring Nov. 11, 2020, 2:25 p.m. UTC | #5
On Wed, Nov 11, 2020 at 8:00 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Rob and Sameer,
>
> Thank you for the patch.
>
> 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.

> > +  ports:
> > +    type: object
> > +    description: |
> > +      If there is more than one port node or 'reg' property present in port
> > +      nodes then '#address-cells' and '#size-cells' properties are required.
> > +      In such cases all port nodes can be grouped under 'ports' independently
> > +      from any other child device nodes a device might have.
>
> Allowing multiple port nodes not grouped in a ports node has created
> complexity, with very little gain. Should we forbid that going forward ?

Yes, that's probably a separate change. The examples need updating
too. We do have a few cases we'll have to support though.

> > +    properties:
> > +      "#address-cells":
> > +        const: 1
> > +
> > +      "#size-cells":
> > +        const: 0
> > +
> > +    patternProperties:
> > +      "^port(@[0-9a-f]+)?$":
> > +        $ref: "#/properties/port"
> > +        type: object
> > +
> > +        properties:
> > +          reg:
> > +            maxItems: 1
> > +
> > +        required:
> > +          - reg
> > +
> > +
>
> Maybe a single blank line ?
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I've gone thru and updated schemas to use this. Primarily to prove out
a meta-schema for it. So I'll be sending out another version.

Rob
Laurent Pinchart Nov. 11, 2020, 2:27 p.m. UTC | #6
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 ;-))

> > > +  ports:
> > > +    type: object
> > > +    description: |
> > > +      If there is more than one port node or 'reg' property present in port
> > > +      nodes then '#address-cells' and '#size-cells' properties are required.
> > > +      In such cases all port nodes can be grouped under 'ports' independently
> > > +      from any other child device nodes a device might have.
> >
> > Allowing multiple port nodes not grouped in a ports node has created
> > complexity, with very little gain. Should we forbid that going forward ?
> 
> Yes, that's probably a separate change. The examples need updating
> too. We do have a few cases we'll have to support though.

Sure, it can be done on top.

> > > +    properties:
> > > +      "#address-cells":
> > > +        const: 1
> > > +
> > > +      "#size-cells":
> > > +        const: 0
> > > +
> > > +    patternProperties:
> > > +      "^port(@[0-9a-f]+)?$":
> > > +        $ref: "#/properties/port"
> > > +        type: object
> > > +
> > > +        properties:
> > > +          reg:
> > > +            maxItems: 1
> > > +
> > > +        required:
> > > +          - reg
> > > +
> > > +
> >
> > Maybe a single blank line ?
> >
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> I've gone thru and updated schemas to use this. Primarily to prove out
> a meta-schema for it. So I'll be sending out another version.
Rob Herring Nov. 11, 2020, 11:03 p.m. UTC | #7
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
Laurent Pinchart Nov. 12, 2020, 7:56 a.m. UTC | #8
Hi Rob,

On Wed, Nov 11, 2020 at 05:03:26PM -0600, Rob Herring wrote:
> On Wed, Nov 11, 2020 at 8:27 AM Laurent Pinchart wrote:
> > 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

We've discussed this before, see

Subject: Re: [PATCH v2 7/9] drm: rcar-du: lvds: Add dual-LVDS panels support
Message-ID: <20190815130834.GM5011@pendragon.ideasonboard.com>

"But what will then happen if you panel has more than two ports (for
audio for instance, or for other types of video links) ? It may not be
possible to always use port 0 and 1 for the LVDS even and odd pixels in
DT bindings of a particular panel or bridge."
Rob Herring Nov. 12, 2020, 8:49 p.m. UTC | #9
On Mon, Nov 2, 2020 at 2:36 PM Rob Herring <robh@kernel.org> 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
>
> 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

I've decided to move this to the dt-schema repo instead[1]. I think
that will be easier to manage dependencies (audio-graph.yaml plus
anything else landing this cycle) than subsystems pulling a shared
branch. I haven't merged it yet, so let me know if any
comments/objections. Note that the meta-schema will have to come a bit
later once existing users are updated (which I have patches for).

Rob

[1] https://github.com/devicetree-org/dt-schema/tree/of-graph
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/graph.txt b/Documentation/devicetree/bindings/graph.txt
index 0415e2c53ba0..b7818d61cef7 100644
--- a/Documentation/devicetree/bindings/graph.txt
+++ b/Documentation/devicetree/bindings/graph.txt
@@ -1,128 +1 @@ 
-Common bindings for device graphs
-
-General concept
----------------
-
-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.
-
-Organisation of ports and endpoints
------------------------------------
-
-Ports are described by child 'port' nodes contained in the device node.
-Each port node contains an 'endpoint' subnode for each remote device port
-connected to this port. If a single port is connected to more than one
-remote device, an 'endpoint' child node must be provided for each link.
-If more than one port is present in a device node or there is more than one
-endpoint at a port, or a port node needs to be associated with a selected
-hardware interface, a common scheme using '#address-cells', '#size-cells'
-and 'reg' properties is used to number the nodes.
-
-device {
-        ...
-        #address-cells = <1>;
-        #size-cells = <0>;
-
-        port@0 {
-	        #address-cells = <1>;
-	        #size-cells = <0>;
-		reg = <0>;
-
-                endpoint@0 {
-			reg = <0>;
-			...
-		};
-                endpoint@1 {
-			reg = <1>;
-			...
-		};
-        };
-
-        port@1 {
-		reg = <1>;
-
-		endpoint { ... };
-	};
-};
-
-All 'port' nodes can be grouped under an optional 'ports' node, which
-allows to specify #address-cells, #size-cells properties for the 'port'
-nodes independently from any other child device nodes a device might
-have.
-
-device {
-        ...
-        ports {
-                #address-cells = <1>;
-                #size-cells = <0>;
-
-                port@0 {
-                        ...
-                        endpoint@0 { ... };
-                        endpoint@1 { ... };
-                };
-
-                port@1 { ... };
-        };
-};
-
-Links between endpoints
------------------------
-
-Each endpoint should contain a 'remote-endpoint' phandle property that points
-to the corresponding endpoint in the port of the remote device. In turn, the
-remote endpoint should contain a 'remote-endpoint' property. If it has one, it
-must not point to anything other than the local endpoint. Two endpoints with
-their 'remote-endpoint' phandles pointing at each other form a link between the
-containing ports.
-
-device-1 {
-        port {
-                device_1_output: endpoint {
-                        remote-endpoint = <&device_2_input>;
-                };
-        };
-};
-
-device-2 {
-        port {
-                device_2_input: endpoint {
-                        remote-endpoint = <&device_1_output>;
-                };
-        };
-};
-
-Required properties
--------------------
-
-If there is more than one 'port' or more than one 'endpoint' node or 'reg'
-property present in the port and/or endpoint nodes then the following
-properties are required in a relevant parent node:
-
- - #address-cells : number of cells required to define port/endpoint
-                    identifier, should be 1.
- - #size-cells    : should be zero.
-
-Optional endpoint properties
-----------------------------
-
-- remote-endpoint: phandle to an 'endpoint' subnode of a remote device node.
-
+This file has moved to 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.
+            $ref: /schemas/types.yaml#/definitions/phandle
+
+        required:
+          - remote-endpoint
+
+  ports:
+    type: object
+    description: |
+      If there is more than one port node or 'reg' property present in port
+      nodes then '#address-cells' and '#size-cells' properties are required.
+      In such cases all port nodes can be grouped under 'ports' independently
+      from any other child device nodes a device might have.
+
+    properties:
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+    patternProperties:
+      "^port(@[0-9a-f]+)?$":
+        $ref: "#/properties/port"
+        type: object
+
+        properties:
+          reg:
+            maxItems: 1
+
+        required:
+          - reg
+
+
+    additionalProperties: false
+
+additionalProperties: true
+
+examples:
+  # Organisation of ports and endpoints:
+  #
+  # Ports are described by child 'port' nodes contained in the device node.
+  # Each port node contains an 'endpoint' subnode for each remote device port
+  # connected to this port. If a single port is connected to more than one
+  # remote device, an 'endpoint' child node must be provided for each link.
+  # If more than one port is present in a device node or there is more than
+  # one endpoint at a port, or a port node needs to be associated with a
+  # selected hardware interface, a common scheme using '#address-cells',
+  # '#size-cells' and 'reg' properties is used to number the nodes.
+  - |
+    device {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        port@0 {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            reg = <0>;
+
+            endpoint@0 {
+                reg = <0>;
+                // ...
+            };
+            endpoint@1 {
+                reg = <1>;
+                // ...
+            };
+        };
+
+        port@1 {
+            reg = <1>;
+
+            endpoint {
+                // ...
+            };
+        };
+    };
+
+  # All 'port' nodes can be grouped under an optional 'ports' node, which
+  # allows to specify #address-cells, #size-cells properties for the 'port'
+  # nodes independently from any other child device nodes a device might
+  # have.
+  - |
+    device {
+        // ...
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                reg = <0>;
+                // ...
+
+                endpoint@0 {
+                    reg = <0>;
+                    // ...
+                };
+                endpoint@1 {
+                    reg = <1>;
+                    // ...
+                };
+            };
+
+            port@1 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                reg = <1>;
+                // ...
+            };
+        };
+    };
+
+  # Links between endpoints:
+  #
+  # Each endpoint should contain a 'remote-endpoint' phandle property that
+  # points to the corresponding endpoint in the port of the remote device.
+  # In turn, the remote endpoint should contain a 'remote-endpoint' property.
+  # If it has one, it must not point to anything other than the local endpoint.
+  # Two endpoints with their 'remote-endpoint' phandles pointing at each other
+  # form a link between the containing ports.
+  - |
+    device-1 {
+        port {
+            device_1_output: endpoint {
+                remote-endpoint = <&device_2_input>;
+            };
+        };
+    };
+
+    device-2 {
+        port {
+            device_2_input: endpoint {
+                remote-endpoint = <&device_1_output>;
+            };
+        };
+    };
+
+...