Re: [PATCH 1/3] dt-bindings: wireless: add ath11k pcie bindings

[Kalle Valo <kvalo@kernel.org>]

Johan Hovold <johan@kernel.org> writes:

> On Mon, Mar 20, 2023 at 08:41:21PM +0200, Kalle Valo wrote:
>
>> + ath11k list
>> 
>> Johan Hovold <johan@kernel.org> writes:
>> 
>> > On Mon, Mar 20, 2023 at 02:22:12PM +0200, Kalle Valo wrote:
>> >> Johan Hovold <johan+linaro@kernel.org> writes:
>> >> 
>> >> > Add devicetree bindings for Qualcomm ath11k PCIe devices such as WCN6856
>> >> > for which the calibration data variant may need to be described.
>> >> >
>> >> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>> >> > ---
>> >> >  .../bindings/net/wireless/pci17cb,1103.yaml   | 56 +++++++++++++++++++
>> >> >  1 file changed, 56 insertions(+)
>> >> >  create mode 100644
>> >> > Documentation/devicetree/bindings/net/wireless/pci17cb,1103.yaml
>> >> 
>> >> I'm confused (as usual), how does this differ from
>> >> bindings/net/wireless/qcom,ath11k.yaml? Why we need two .yaml files?
>> >
>> > Almost none of bindings/net/wireless/qcom,ath11k.yaml applies to WCN6856
>> > when using PCIe (e.g. as most properties are then discoverable).
>> >
>> > We could try to encode everything in one file, but that would likely
>> > just result in a big mess of a schema with conditionals all over.
>> 
>> Ah, so the current qcom,ath11k.yaml would be only for ath11k AHB devices
>> and this new file is only for ath11k PCI devices?
>
> Right, there would two separate schema files for the two device classes.
>
>> But why still the odd
>> name pci17cb,1103.yaml? It's not really descriptive and I'm for sure
>> will not remember that pci17cb,1103.yaml is for ath11k :)
>
> Yeah, it's not the best name from that perspective, but it follows the
> current convention of naming the schema files after the first compatible
> added.
>
> That said, we don't have many schemas for PCI devices so perhaps we can
> establish a new convention for those. Perhaps by replacing the numerical
> ids with what we'd use if these were platform devices (e.g.
> 'qcom,wcn6855.yaml').
>
> As long as the DT maintainers are OK with it, I'd also be happy with
> something like you suggest below:
>
> 	qcom,ath11k-ahb.yaml
> 	qcom,ath11k-pci.yaml
>
> (or simply not renaming the current file 'qcom,ath11k.yaml') but I have
> gotten push back on that in the past.

Ok, maybe it's then better not to try renaming qcom,ath11k.yaml and keep
it as is.

>> Also it doesn't look good that we have qcom,ath11k-calibration-variant
>> documented twice now. I'm no DT expert but isn't there any other way? Is
>> it possible to include other files? For example, if we would have three
>> files:
>> 
>> qcom,ath11k.yaml
>> qcom,ath11k-ahb.yaml
>> qcom,ath11k-pci.yaml
>> 
>> Then have the common properties like ath11k-calibration-variant in the
>> first file and ahb/pci files would include that.
>
> That should be possible, but it's not necessarily better as you'd then
> have to look up two files to see the bindings for either device class
> (and as far as I can tell there would not be much sharing beyond this
> single property).
>
> Note that the property could just have well have been named
> 'qcom,calibration-variant' and then it would be shared also with the
> ath10k set of devices which currently holds another definition of what
> is essentially the same property ('qcom,ath10k-calibration-variant').

Oh man, having it as 'qcom,calibration-variant' would have been so much
better. Oh well, too late now :(

Thanks for explaining all this.

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