Re: [PATCH] arm64: dts: renesas: white-hawk-cpu: Move avb0 reset gpio to mdio node

[Marek Vasut <marex@denx.de>]

On 10/29/24 9:26 AM, Geert Uytterhoeven wrote:

[...]

>>>>>> revision, we can revisit this discussion ? Maybe bootloader-applied DTOs
>>>>>> could work then ?
>>>>>
>>>>> So, what would you suggest when the PHY nodes would not have compatible
>>>>> strings?
>>>> I hope I already answered that question before.
>>>
>>> Sorry, I may have missed that?
>>>
>>> I really prefer not having the PHY compatible strings, as DT should
>>> describe only what cannot be auto-detected.
>> See paragraph above (*). My take on this is the exact opposite, better
>> describe the PHY in DT fully, including compatible strings, so that if
>> the PHY driver needs to do some sort of bring up tweak/fix/errata
>> workaround/... , it can do so by matching on the compatible string
>> without trying to bring the PHY up in some generic and potentially
>> problematic way.
>>
>> The MDIO bus is not discoverable the same way as PCIe or USB is, so I
>> don't think the "DT should describe only what cannot be detected" is
>> really applicable to MDIO bus the same way it applies to PCIe or USB.
> 
> So you think this is similar to SPI NOR, where most FLASHes can be
> discovered with the JEDEC READ ID opcode?

Possibly, if you take broken-flash-reset DT property into account 
somehow. Even SPI NOR does require a proper reset after all, else the 
READ ID opcode may not work.

> See commit 4b0cb4e7ab2f777c
> ("dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles"),
> which clarified why no new compatible values are accepted.
This works as long as your SPI NOR reset works.