Re: [PATCH 12/13] dt-bindings: lpspi: Document nxp,lpspi-pincfg property

[James Clark]

On 18/08/2025 4:39 pm, Frank Li wrote:
> On Mon, Aug 18, 2025 at 03:47:45PM +0100, James Clark wrote:
> > On 14/08/2025 7:19 pm, Frank Li wrote:
> > > On Thu, Aug 14, 2025 at 05:06:52PM +0100, James Clark wrote:
> > > > Document the two valid pincfg values and the defaults.
> > > >
> > > > Although the hardware supports two more values for half-duplex modes,
> > > > the driver doesn't support them so don't document them.
> > >
> > > binding doc should be first patch before drivers.
> > >
> > > binding descript hardware not driver, you should add all regardless if
> > > driver support it.
> >
> > Replied to same on "[PATCH 10/13] spi: spi-fsl-lpspi: Add compatible for
> > S32G"
> >
> > > > Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
> > > > ---
> > > >    Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml | 14 ++++++++++++++
> > > >    1 file changed, 14 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml b/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml
> > > > index ce7bd44ee17e..3f8833911807 100644
> > > > --- a/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml
> > > > +++ b/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml
> > > > @@ -70,6 +70,19 @@ properties:
> > > >      power-domains:
> > > >        maxItems: 1
> > > >
> > > > +  nxp,pincfg:
> > > > +    description:
> > > > +      'Pin configuration value for CFGR1.PINCFG.
> > > > +        - "sin-in-sout-out": SIN is used for input data and SOUT is used for
> > > > +                             output data
> > > > +        - "sout-in-sin-out": SOUT is used for input data and SIN is used for
> > > > +                             output data
> > > > +      If no value is specified then the default is "sin-in-sout-out" for host
> > > > +      mode and "sout-in-sin-out" for target mode.'
> > >
> > > why need this? are there varible at difference boards? look like default
> > > is more make sense.
> >
> > + Larissa. I think this might also be a question for the hardware designers
> > about why the feature to swap the pins was deemed worth including.
> >
> > I'm assuming the flexibility is given for routing reasons. If you have
> > another device with the pins in one order then you can route it without a
> > via if they happen to be in the same order.
>
> DT team need reason to judge if a new property is reasonable/neccesary. You
> need  mention the reason why need this property. Here, some board design
> swap sin/sout.

Let's wait for Larisa to reply. If there's no board and it was only for 
testing maybe we can drop it.