[PATCH RFC 1/2] dt-bindings: mfd: aspeed-lpc: Document lpcN alias for multi-instance SoCs

[Lee Jones]

On Thu, 23 Jul 2026, Yu-Che Hsieh wrote:

> Some SoCs (e.g. AST2700) expose more than one physical LPC controller
> instance. Downstream devices such as KCS channels need a stable,
> globally-unique index derived from which LPC controller instance they
> belong to, so document the "lpcN" alias convention on the LPC
> controller node that lets DT authors assign a fixed index per
> instance, mirroring the existing alias-based numbering convention used
> by mmc/i2c/spi/serial.
> 
> Signed-off-by: Yu-Che Hsieh <yc_hsieh at aspeedtech.com>

Why is this RFC?  What's stopping me from applying this now?

> ---
>  Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> index cbc3a2485a2f..81c12e0fb312 100644
> --- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> +++ b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> @@ -35,6 +35,13 @@ description:
>    configuration, therefore the host portion of the controller is exposed as a
>    syscon as a means to arbitrate access.
>  
> +  On SoCs that expose more than one LPC controller instance, it is possible to
> +  assign a fixed index to a given instance (and thus to downstream devices
> +  such as KCS channels that must be uniquely identified system-wide) by
> +  defining an "lpcN" alias for it in the /aliases device tree node. If no such
> +  alias is present, the SoC is treated as having a single LPC controller
> +  instance.
> +
>  properties:
>    compatible:
>      items:
> 
> -- 
> 2.34.1
> 

-- 
Lee Jones