On 02/28/2017 09:22 PM, Rob Herring wrote: > On Tue, Feb 28, 2017 at 9:14 AM, Ulf Hansson <ulf.hans...@linaro.org> 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
yet the bindings for power-domains (for consumer devices) only allows for one powerdomain to be associated with a device. > 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. > > Rob > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
