Re: [PATCH v2] spi: dt-bindings: jcore,spi: convert spi-jcore to dtschema

[Rob Herring <robh@xxxxxxxxxx>]

On Fri, Mar 22, 2024 at 07:49:57AM +0100, Krzysztof Kozlowski wrote:
> On 22/03/2024 07:34, Krzysztof Kozlowski wrote:
> > On 22/03/2024 07:23, Kousik Sanagavarapu wrote:
> >> On Fri, 22 Mar 2024, 11:33 Krzysztof Kozlowski, <
> >> krzysztof.kozlowski@xxxxxxxxxx> wrote:
> >>
> >>> On 21/03/2024 19:02, Kousik Sanagavarapu wrote:
> >>>
> >>>> +  spi-max-frequency:
> >>>> +    $ref: /schemas/types.yaml#/definitions/uint32
> >>>
> >>> No, drop. From which other SPI binding did you take it? I asked you to
> >>> look at existing code.
> >>>
> >>
> >> Without this, "make dt_binding_check" would break though, right at the
> >> position in the example where "spi-max-frequency" is used.  That was
> >> also the reason why additionalProperties was set to true in the last
> >> iteration, but after reading the doc more carefully I realized that was
> >> wrong after you pointed it out.
> >>
> >> I followed along bindings/spi/nvidia,tegra114-spi.yaml.
> > 
> > OK, you are right, the property is used here in controller node, however
> > Linux driver never parsed it. It was never used, so I propose to drop it
> > from the binding and example. You can mention in commit msg that
> > spi-max-frequency was not documented thus you drop it from the example.
> > 
> > DTS should be fixed as well. I'll send a patch for it.
> 
> Cc Daniel,
> 
> BTW, J2 core is rather odd platform to work on... Even cross compiling
> and building that DTB is tricky. If I failed, I have doubts that you
> tested the DTS with your binding.
> 
> This applies to all GSoC or some Linux Mentorship programs: I suggest to
> choose for conversion bindings with more users and bigger possible
> impact. So first I would look at ARM64 and ARMv7 platforms. We still
> have around 1000 and 3500 unique warnings about undocumented compatibles
> for ARM64 defconfig and ARM multi_v7! That's the platforms you should
> choose.
> 
> Not SuperH, ARC, or whatever with only one DTS which is difficult to
> build for regular developer.

To add to this, either ask DT maintainers what would be useful to work 
on or you can look here[1][2] to see what are the top occurring 
undocumented (by schema) compatibles.

Rob

[1] https://gitlab.com/robherring/linux-dt/-/jobs/6453674734
[2] https://gitlab.com/robherring/linux-dt/-/jobs/6453674732