Re: [PATCH 4/7] dt-bindings: spi: stm32: add bindings regarding stm32h7 spi slave

[Valentin CARON]

On 4/28/23 23:46, Rob Herring wrote:
> On Fri, Apr 28, 2023 at 02:15:21PM +0200, Valentin Caron wrote:
> > From: Alain Volmat <alain.volmat@xxxxxxxxxxx>
> >
> > Update the spi-stm32 binding yaml regarding to the SPI slave support.
> Why? What problem are you trying to solve.
To add some documentation about cs-gpios and don't allow to use
spi-slave property with st,stm32f4-spi compatible.

I will specify this in next patchset.

> > Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
> > Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx>
> > ---
> >   Documentation/devicetree/bindings/spi/st,stm32-spi.yaml | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml
> > index c599eb359d56..1d26fa2658c5 100644
> > --- a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml
> > +++ b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml
> > @@ -27,6 +27,7 @@ allOf:
> >       then:
> >         properties:
> >           st,spi-midi-ns: false
> > +        spi-slave: false
> >   
> >   properties:
> >     "#address-cells": true
> > @@ -62,6 +63,13 @@ properties:
> >         - const: rx
> >         - const: tx
> >   
> > +  cs-gpios:
> > +    description:
> > +      In case of spi-slave not defined, cs-gpios behave as defined in
> > +      spi-controller.yaml.
> > +      In case of spi-slave defined, if <0>, indicate that SS should be
> > +      detected via the dedicated HW pin
> I don't understand. I though cs-gpios was for master mode. You want to
> define 'cs-gpios = <0>;'? How would that be different than just omitting
> cs-gpios?
>
> Rob
We try to keep consistency with spi master, but, as you said, it is useless.
I will remove it in next patchset.

Thanks,
Valentin