Re: [PATCH v2 1/6] dt-bindings: mfd: add NXP MC33978/MC34978 MSDI

[Krzysztof Kozlowski <krzk@kernel.org>]

On Tue, Mar 03, 2026 at 05:10:20PM +0100, Oleksij Rempel wrote:
> Hi Krzysztof and Rob,
> 
> On Tue, Mar 03, 2026 at 08:40:55AM -0600, Rob Herring (Arm) wrote:
> > >  .../devicetree/bindings/mfd/nxp,mc33978.yaml  | 114 ++++++++++++++++++
> > >  .../bindings/pinctrl/nxp,mc33978-pinctrl.yaml |  82 +++++++++++++
> > >  2 files changed, 196 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/mfd/nxp,mc33978.yaml
> > >  create mode 100644 Documentation/devicetree/bindings/pinctrl/nxp,mc33978-pinctrl.yaml
> > > 
> > 
> > My bot found errors running 'make dt_binding_check' on your patch:
> > 
> > yamllint warnings/errors:
> > 
> > dtschema/dtc warnings/errors:
> > /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/mfd/nxp,mc33978.example.dtb: gpio@0 (nxp,mc33978): $nodename:0: 'gpio@0' does not match '^mux-controller(@.*|-([0-9]|[1-9][0-9]+))?$'
> > 	from schema $id: http://devicetree.org/schemas/mux/mux-controller.yaml
> > 
> 
> Folding the mux node into the parent as suggested [1] causes this error.
> Because the parent now has #mux-control-cells, the generic
> mux-controller.yaml forces the node name to be mux-controller. Since
> this chip is primarily a switch/GPIO controller, naming the parent SPI
> node mux-controller@0 is misleading.
> 
> What is the preferred way to go here?

https://www.nxp.com/products/interfaces/multi-switch-detection-interface/22-i-o-msdi-programmable-current-analog-mux:MC33978

Name of the mc33978 device is "programmable analog mux" and further
description says "analog multiplexer for reading analog inputs ", so I
don't find "mux-controller" a confusing name. It is EXACTLY a
mux, so mux-controller.

Anyway if you want gpio, then please add a patch extending the pattern
in mux-controller.yaml to allow "gpio".

Alternative, because it is rather a mux than a controller of a mux,
would be to call it just "mux" or "io-mux" (maybe the latter, since we
have "i2c-mux" in the spec) and allow that pattern to be in
mux-controller.


Best regards,
Krzysztof