Subject: Re: [PATCH 2/8] dt-bindings: nvmem: add transformation bindings

From: Rob Herring <[email-masked]>
Date: Tue, 4 Jan 2022 09:03:54 -0600

On Tue, Dec 28, 2021 at 03:25:43PM +0100, Michael Walle wrote:
> Just add a simple list of the supported devices which need a nvmem
> transformations.
> 
> Also, since the compatible string is prepended to the actual nvmem
> compatible string, we need to match using "contains" instead of an exact
> match.
> 
> Signed-off-by: Michael Walle <[email-masked]>
> ---
>  .../devicetree/bindings/mtd/mtd.yaml          |  7 +--
>  .../bindings/nvmem/nvmem-transformations.yaml | 46 +++++++++++++++++++
>  2 files changed, 50 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/nvmem/nvmem-transformations.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mtd/mtd.yaml b/Documentation/devicetree/bindings/mtd/mtd.yaml
> index 376b679cfc70..0291e439b6a6 100644
> --- a/Documentation/devicetree/bindings/mtd/mtd.yaml
> +++ b/Documentation/devicetree/bindings/mtd/mtd.yaml
> @@ -33,9 +33,10 @@ patternProperties:
>  
>      properties:
>        compatible:
> -        enum:
> -          - user-otp
> -          - factory-otp
> +        contains:
> +          enum:
> +            - user-otp
> +            - factory-otp

If the addition is only compatible strings, then I would just add them 
here. Otherwise this needs to be structured a bit differently. More on 
that below.

>  
>      required:
>        - compatible
> diff --git a/Documentation/devicetree/bindings/nvmem/nvmem-transformations.yaml b/Documentation/devicetree/bindings/nvmem/nvmem-transformations.yaml
> new file mode 100644
> index 000000000000..8c8d85fd6d27
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/nvmem-transformations.yaml
> @@ -0,0 +1,46 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/nvmem/nvmem-transformations.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NVMEM transformations Device Tree Bindings
> +
> +maintainers:
> +  - Srinivas Kandagatla <[email-masked]>
> +
> +description: |
> +  This is a list NVMEM devices which need transformations.
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +        - enum:
> +          - kontron,sl28-vpd
> +        - const: user-otp
> +      - const: user-otp

This will be applied to any node containing 'user-otp'. You need a 
custom 'select' to avoid that.

> +
> +required:
> +  - compatible
> +
> +additionalProperties: true

True is only allowed for common schema intended to be included (i.e. a 
$ref) by other schemas. IOW, ones that are incomplete on their own. So 
you need to reference mtd.yaml and make this 'unevaluatedProperties: false'.

> +
> +examples:
> +  - |
> +    otp-1 {
> +            compatible = "kontron,sl28-vpd", "user-otp";
> +            #address-cells = <1>;
> +            #size-cells = <1>;
> +
> +            serial@2 {
> +                    reg = <2 15>;
> +            };
> +
> +            base_mac_address: base-mac-address@17 {
> +                    #nvmem-cell-cells = <1>;
> +                    reg = <17 6>;
> +            };
> +    };
> +
> +...
> -- 
> 2.30.2
> 
>