Re: [PATCH 2/2] dt-bindings: PCI: mediatek-gen3: Add support for controlling power and reset

[Krzysztof Kozlowski]

On 03/02/2023 10:38, Jian Yang (杨戬) wrote:
>>> +  pcie12v-supply:
>>> +    description:
>>> +      The regulator phandle that provides 12V power to downstream
>>> component.
>>> +
>>> +  dsc-reset-gpios:
>>> +    description:
>>> +      The reset GPIO of a downstream component.
>>
>> Why you cannot use standard reset-gpios property?
> 
> The "dsc-reset-gpios" represents an extra reset pin other than PERST#
> required by a PCIe downstream device. But the "reset-gpios", described
> in "pci.txt", represents the PERST#. So I tend to add a new property to
> meet this requirement.

OK

>>
>>> +    description:
>>> +      The delay time between assertion and de-assertion of a
>>> downstream
>>> +      component's reset GPIO.
>>
>> Why this should be a property of DT?
> 
> Same as the reason I described above. I suppose we need to add a
> property to let user determine the delay time due to differences
> in requirements between various devices.

No, I don't think we want individual properties like that. There is
ongoing discussion about this:
https://lore.kernel.org/all/20221214095342.937303-1-alexander.stein@xxxxxxxxxxxxxxx/

Feedback is welcomed - there. Don't create your own half-baked delays
for different hardware designs.

Best regards,
Krzysztof