Re: [PATCH v2 03/19] dt-bindings: power: mediatek: Add bindings for MediaTek SCPSYS

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

On 19/07/2022 10:17, Tinghan Shen wrote:
>>> +    syscon@10006000 {
>>> +        compatible = "mediatek,scpsys", "syscon", "simple-mfd";
>>
>> This should be a SoC-specific compatible (and filename).
> 
> Ok. I think that you mean "mediatek,mt8195-scpsys".
> I'll update it in next version.

Yes.

> 
>>
>>> +        reg = <0x10006000 0x100>;
>>> +
>>> +        spm: power-controller {
>>
>> I think you created before less-portable, quite constrained bindings for
>> power controller. You now require that mt8195-power-controller is always
>> a child of some parent device which will share its regmap/MMIO with it.
>>
>> And what if in your next block there is no scpsys block and power
>> controller is the scpsys alone? It's not possible with your bindings.
> 
> Do you mean a power controller node that looks like this?
> 
> scpsys: power-controller@10006000 {
> 	compatible = "mediatek,mt6797-scpsys";
> 	#power-domain-cells = <1>;
> 
> 	// ...
> };

Yes, I mean, with an unit address.

> 
>>
>> Wouldn't it be better to assign some address space to the
>> power-controller (now as an offset from scpsys)?
> 
> Is this mean adding an offset after the node name?
> 
> spm: power-controller@0 {

This or above. I think it does not matter for the bindings - it's an
implementation detail, whether you give to the child absolute SoC
address or you give an bus-specific (scpsys) sub-address/offset.

The point is that you have an unit address, thus in the future this
could be a device node separate from scpsys.

Best regards,
Krzysztof