Hi Rob,
On Tue, Feb 28, 2017 at 4:52 PM, Rob Herring <robh@xxxxxxxxxx> wrote:
> On Tue, Feb 28, 2017 at 9:14 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>> [...]
>>
>>>> ---> Parent domain-2 (Contains Perfomance states)
>>>> |
>>>> |
>>>> C.) DeviceX ---> Parent-domain-1 |
>>>> |
>>>> |
>>>> ---> Parent domain-3 (Contains Perfomance states)
>>>
>>> I'm a bit confused. How does a domain have 2 parent domains?
>>
>> This comes from the early design of the generic PM domain, thus I
>> assume we have some HW with such complex PM topology. However, I don't
>> know if it is actually being used.
>>
>> Moreover, the corresponding DT bindings for "power-domains" parents,
>> can easily be extended to cover more than one parent. See more in
>> Documentation/devicetree/bindings/power/power_domain.txt
>
> I could easily see device having 2 power domains. For example a cpu
> may have separate domains for RAM/caches and logic. And nesting of
> power domains is certainly common, but a power domain being contained
> in 2 different parents? I don't even see how that is possible in the
> physical design. Now if we're mixing PM and power domains again and
> the cpu device is pointing to the cpu PM domain which contains 2 power
> domains, then certainly that is possible.
One of them could be a power area, the other a clock domain.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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