Re: [PATCH v3 2/3] dt-bindings: phy: qcom-edp: Add X1E80100 PHY compatibles

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 08/12/2023 13:35, Dmitry Baryshkov wrote:
>>>>> Same applies to the displayport-controller. It can either drive the DP
>>>>> or eDP output, hardware-wise it is the same.
>>>>
>>>> Therefore what I proposed was correct - the block which uses the phy
>>>> configures its mode. Because this part:
>>>>   "this phy is of this type on this board".
>>>> is not true. The phy is both types.
>>>
>>> But hopefully you don't mean using #phy-cells here. There are no
>>> sub-PHYs or anything like that.
>>
>> I am exactly talking about phy-cells. Look at first example from Abel's
>> code.
> 
> I always had an impression that #foo-cells means that there are
> different units within the major handler. I.e. #clock-cells mean that
> there are several different clocks, #reset-cells mean that there are
> several resets, etc.
> Ok, maybe this is not a perfect description. We need cells to identify
> a particular instance within the major block. Maybe that sounds more
> correct.

No, the cells have also meaning of additional arguments. See usage of
phy-type (not the one here, but the correct one) and PWMs.

> 
> For the USB+DP PHY we use #phy-cells to select between USB3 and DP
> PHYs. But for these PHYs we do not have sub-devices, sub-blocks, etc.
> There is a single PHY which works in either of the modes.

Is it different than case here?

> 
> Last, but not least, using #phy-cells in this way would create
> asymmetry with all the other PHYs (and especially other QMP PHYs)
> present on these platforms.

OK. Is phy-type not something different?

> 
> If you feel that phy-type is not an appropriate solution, I'd vote for
> not having the type in DT at all, letting the DP controller determine
> the proper mode on its own.

Can we do it? That's BTW the best option.

Best regards,
Krzysztof