Re: [PATCH 1/7] dt-bindings: Add support for export-symbols node

[Luca Ceresoli]

Hi Hervé,

On Mon,  9 Dec 2024 16:18:19 +0100
Herve Codina <herve.codina@xxxxxxxxxxx> wrote:

> An export-symbols node allows to export symbols for symbols resolution
> performed when applying a device tree overlay.
> 
> When a device tree overlay is applied on a node having an export-symbols
> node, symbols listed in the export-symbols node are used to resolve
> undefined symbols referenced from the overlay.
> 
> This allows:
>   - Referencing symbols from an device tree overlay without the need to
>     know the full base board. Only the connector definition is needed.
> 
>   - Using the exact same overlay on several connectors available on a given
>     board.
> 
> For instance, the following description is supported with the
> export-symbols node:
>  - Base device tree board A:
>     ...
>     foo_connector: connector1 {
>         export-symbols {
>            connector = <&foo_connector>;
>         };
>     };
> 
>     bar_connector: connector2 {
>         export-symbols {
>            connector = <&bar_connector>;
>         };
>     };
>     ...
> 
>  - Base device tree board B:
>     ...
>     front_connector: addon-connector {
>         export-symbols {
>            connector = <&front_connector>;
>         };
>     };
>     ...
> 
>  - Overlay describing an addon board the can be connected on connectors:
>     ...
>     node {
>         ...
>         connector = <&connector>;
>         ...
>     };
>     ...
> 
> Thanks to the export-symbols node, the overlay can be applied on
> connector1 or connector2 available on board A but also on
> addon-connector available on board B.
> 
> Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> ---
>  .../devicetree/bindings/export-symbols.yaml   | 43 +++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/export-symbols.yaml
> 
> diff --git a/Documentation/devicetree/bindings/export-symbols.yaml b/Documentation/devicetree/bindings/export-symbols.yaml
> new file mode 100644
> index 000000000000..0e404eff8937
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/export-symbols.yaml
> @@ -0,0 +1,43 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/export-symbols.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Export symbols
> +
> +maintainers:
> +  - Herve Codina <herve.codina@xxxxxxxxxxx>
> +
> +description: |
> +  An export-symbols node allows to export symbols for symbols resolution
> +  performed when applying a device tree overlay.
> +
> +  When a device tree overlay is applied on a node having an export-symbols
> +  node, symbols listed in the export-symbols node are used to resolve undefined
> +  symbols referenced from the overlay.
> +
> +properties:
> +  $nodename:
> +    const: export-symbols
> +
> +patternProperties:
> +  "^[a-zA-Z_]?[a-zA-Z0-9_]*$":

I think the '?' should not be there: "^[a-zA-Z_][a-zA-Z0-9_]*$".

Otherwise LGTM.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com