[PATCH v4 01/10] dt-bindings: iommu: Add Translation Buffer Unit bindings

[Rob Herring]

On Thu, Feb 01, 2024 at 01:05:20PM -0800, Georgi Djakov wrote:
> Add common bindings for the TBUs to describe their properties. The
> TBUs are modelled as child devices of the IOMMU and each of them is
> described with their compatible, reg and stream-id-range properties.
> There could be other implementation specific properties to describe
> any resources like clocks, regulators, power-domains, interconnects
> that would be needed for TBU operation. Such properties will be
> documented in a separate vendor-specific TBU schema.
> 
> Signed-off-by: Georgi Djakov <quic_c_gdjako at quicinc.com>
> ---
>  .../devicetree/bindings/iommu/arm,smmu.yaml   | 14 ++++++++++
>  .../devicetree/bindings/iommu/tbu-common.yaml | 28 +++++++++++++++++++
>  2 files changed, 42 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iommu/tbu-common.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> index a4042ae24770..ba3237023b39 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> @@ -235,6 +235,20 @@ properties:
>        enabled for any given device.
>      $ref: /schemas/types.yaml#/definitions/phandle
>  
> +  '#address-cells':
> +    enum: [ 1, 2 ]
> +
> +  '#size-cells':
> +    enum: [ 1, 2 ]
> +
> +  ranges: true
> +
> +patternProperties:
> +  "^tbu@[0-9a-f]+$":
> +    description: TBU child nodes
> +    type: object
> +    $ref: tbu-common.yaml#

       additionalProperties: false


However, that's going to break with the extra QCom properties. In 
json-schema, you can't have 2 schemas and extend the properties of 
their child nodes. The validator doesn't "see" the child node schemas at 
the same time. You are going to have to move QCom SMMU to its own schema 
and remove it from arm,smmu.yaml.

Rob