| Message ID | 20201102203656.220187-2-robh@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dt-bindings: Convert graph bindings to json-schema | expand |
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>
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
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
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>; > + }; > + }; > + }; > + > +...
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
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.
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
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."
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 --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>; + }; + }; + }; + +...