Re: [PATCH 1/2] dt-bindings: mfd: syscon: Disallow simple-bus with syscon

[Rob Herring (Arm)]

On Sun, 31 May 2026 13:04:05 +0200, Krzysztof Kozlowski wrote:
> "syscon" is a system controller with registers having their own
> functions, thus not really a trivial MMIO simple bus.  "simple-bus" on
> the other hand is just a bus on which multiple devices sit and the
> "simple" means no functions are allowed here.
> 
> Combination of both "syscon" and "simple-bus" is abuse of DT for easier
> instantiating of Linux device drivers so add a schema to disallow that.
> 
> Unfortunately there are a few old cases of that patterns, so add
> exceptions:
> 
> 1. "cznic,turris1x-cpld" and "img,pistachio-cr-periph" are already used
>    in upstream DTS.
> 
> 2. TI has several DTSI with a child of SCM device (e.g. "ti,am3-scm")
>    using "syscon" and "simple-bus" but without a dedicated compatible
>    documented anywhere.  Add new compatibles for such cases.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
> ---
>  .../bindings/mfd/syscon-common.yaml           | 27 +++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 

Acked-by: Rob Herring (Arm) <robh@xxxxxxxxxx>