Re: [PATCH v2 03/14] dt-bindings: pci: Add common schema for devices accessible through PCI BARs

[Rob Herring <robh@xxxxxxxxxx>]

On Mon, Oct 07, 2024 at 02:39:46PM +0200, Andrea della Porta wrote:
> Common YAML schema for devices that exports internal peripherals through
> PCI BARs. The BARs are exposed as simple-buses through which the
> peripherals can be accessed.
> 
> This is not intended to be used as a standalone binding, but should be
> included by device specific bindings.
> 
> Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
> ---
>  .../devicetree/bindings/pci/pci-ep-bus.yaml   | 69 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 70 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml b/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> new file mode 100644
> index 000000000000..9d7a784b866a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> @@ -0,0 +1,69 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/pci-ep-bus.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Common properties for PCI MFD endpoints with peripherals addressable from BARs.
> +
> +maintainers:
> +  - Andrea della Porta  <andrea.porta@xxxxxxxx>
> +
> +description:
> +  Define a generic node representing a PCI endpoint which contains several sub-
> +  peripherals. The peripherals can be accessed through one or more BARs.
> +  This common schema is intended to be referenced from device tree bindings, and
> +  does not represent a device tree binding by itself.
> +
> +properties:
> +  "#address-cells":
> +    const: 3
> +
> +  "#size-cells":
> +    const: 2
> +
> +  ranges:
> +    minItems: 1
> +    maxItems: 6
> +    items:
> +      maxItems: 8
> +      additionalItems: true
> +      items:
> +        - maximum: 5  # The BAR number
> +        - const: 0
> +        - const: 0
> +
> +patternProperties:
> +  "^pci-ep-bus@[0-5]$":
> +    $ref: '#/$defs/pci-ep-bus'

This should just be:

additionalProperties: true

properties:
  compatible:
    const: simple-bus

required:
  - compatible

Then the compatible will cause simple-bus.yaml to be applied to this 
node.

> +    description:
> +      One node for each BAR used by peripherals contained in the PCI endpoint.
> +      Each node represent a bus on which peripherals are connected.
> +      This allows for some segmentation, e.g. one peripheral is accessible
> +      through BAR0 and another through BAR1, and you don't want the two
> +      peripherals to be able to act on the other BAR. Alternatively, when
> +      different peripherals need to share BARs, you can define only one node
> +      and use 'ranges' property to map all the used BARs.
> +
> +required:
> +  - ranges
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +$defs:
> +  pci-ep-bus:
> +    type: object
> +    additionalProperties: true
> +    properties:
> +      compatible:
> +        const: simple-bus
> +      dma-ranges: true
> +      ranges: true
> +      "#address-cells": true
> +      "#size-cells": true
> +    required:
> +      - compatible
> +      - ranges
> +      - '#address-cells'
> +      - '#size-cells'

All this should be covered by simple-bus.yaml.

Rob