Re: [PATCH v2 1/6] dt-bindings: reserved-memory: Add Owl SoC serial number binding

[Rob Herring <robh@xxxxxxxxxx>]

On Tue, Mar 30, 2021 at 04:48:16PM +0300, Cristian Ciocaltea wrote:
> Add devicetree binding for the Actions Semi Owl SoC serial number
> reserved-memory range.
> 
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxx>
> ---
>  .../actions,owl-soc-serial.yaml               | 53 +++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/reserved-memory/actions,owl-soc-serial.yaml
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/actions,owl-soc-serial.yaml b/Documentation/devicetree/bindings/reserved-memory/actions,owl-soc-serial.yaml
> new file mode 100644
> index 000000000000..41b71f47ee6c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reserved-memory/actions,owl-soc-serial.yaml
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/reserved-memory/actions,owl-soc-serial.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Actions Semi Owl reserved-memory for SoC serial number
> +
> +maintainers:
> +  - Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxx>
> +
> +description: |
> +  Provide access to the memory region where the two parts of the Actions
> +  Semi Owl SoC serial number (low & high) can be read from. This information
> +  is provided by the bootloader, hence expose it under /reserved-memory node.
> +
> +  Please refer to reserved-memory.txt in this directory for common binding
> +  part and usage.
> +
> +  This is currently supported only on the S500 SoC variant.
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: actions,owl-soc-serial
> +      - items:
> +          - enum:
> +              - actions,s500-soc-serial
> +          - const: actions,owl-soc-serial
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: true
> +
> +examples:
> +  - |
> +    reserved-memory {
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +        ranges;
> +
> +        soc_serial: soc-serial@800 {
> +            compatible = "actions,s500-soc-serial", "actions,owl-soc-serial";
> +            reg = <0x800 0x8>;

You end up wasting a whole page of memory for 8 bytes. It may be better 
to copy this to a DT property ('serial-number' is already a defined root 
property).

Rob