Re: [PATCH v2 1/7] dt-bindings: Add support for export-symbols node

On Wed, 30 Apr 2025 14:51:45 +0200
Herve Codina <[email protected]> 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 <[email protected]>
> Tested-by: Ayush Singh <[email protected]>

Reviewed-by: Luca Ceresoli <[email protected]>

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