Re: [PATCH v2 3/3] dt-bindings: iio: accel: adxl345: Add spi-3wire

[Lothar Rubusch]

On Sat, Mar 23, 2024 at 3:27 PM Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxx> wrote:
>
> On 23/03/2024 13:04, Lothar Rubusch wrote:
> > On Fri, Mar 22, 2024 at 3:17 AM Rob Herring <robh@xxxxxxxxxx> wrote:
> >>
> >> On Fri, Mar 22, 2024 at 12:37:13AM +0000, Lothar Rubusch wrote:
> >>> Provide the optional spi-3wire in the example.
> >>
> >> That doesn't match the diff as you don't touch the example. But really,
> >> this should say why you need spi-3wire.
> >
> > I understand. The change does not add anything to the example. which
> > is definitely wrong.
> > Anyway I'm unsure about this change in particular. I know the spi-3wire
> > binding exists and can be implemented. Not all spi devices offer it. Not all
> > drivers implement it. My patch set tries to implement spi-3wire for the
> > particular accelerometer.
> > Do I need to add something here to dt-bindings documentation of the
> > adxl345? Or, as an optional spi feature, is it covered anyway by
> > documentation of optional spi bindings? So, should I refrase this particular
> > patch or may I drop it entirely? Could you please clarify.
>
> Whether you need to change bindings or not, dtbs_check will tell you.
> Just run dtbs_check on your DTS.
>

I'm not changing upstream DTS. At most, the documentation should
mention something.

> It does not look like you tested the DTS against bindings. Please run
> `make dtbs_check W=1` (see
> Documentation/devicetree/bindings/writing-schema.rst or
> https://www.linaro.org/blog/tips-and-tricks-for-validating-devicetree-sources-with-the-devicetree-schema/
> for instructions).
>

No, I didn't. dtbs_check did not work right out of the box, but it
sounds great and I will figure out. Currently my setup is a bit
customized. I compile the modules out of tree, dockerized with several
DTBOs. I use an automized setup to verify spi, spi-3wire and i2c
probing still works on the hardware. It is tested at least somehow.

> AFAIR, spi-3wire requires being explicitly mentioned in the device bindings.
>
>
> Best regards,
> Krzysztof
>