Re: [PATCH V2 1/2] PM / Domains: Introduce domain-performance-states binding

Rajendra Nayak
2017-01-06T10:36:26Z

On 01/06/2017 03:53 PM, Viresh Kumar wrote:
> On 06-01-17, 15:42, Rajendra Nayak wrote:
>> I read through that discussion, and I thought that was to do we
>> handling multiple powerdomains with performance states
>> (or in other words multiple voltage rails controlled by the M3)
>
> I thought about it as multiple power domains available for a device,
> and the device will be in a single domain out of those at a time. So
> perhaps it is about the problem you mentioned.
>
>> What I was pointing to, was that devices quite often (again on qcom
>> platforms) have a power-switch (gdscs as we call it) which are modeled
>> as powerdomains (which have nothing to do with taking to the M3 core),
>> and with the proposed bindings one or more voltage rails controlled by the M3
>> also as powerdomains associated with a device and the bindings have just one
>> power-domains property in the device node, which runtime PM would use
>> to power_on/off the device and OPP core would use to set the performance
>> state?
>>
>> + leaky-device@12350000 {
>> + compatible = "foo,i-leak-current";
>> + reg = <0x12350000 0x1000>;
>> + power-domains = <&power 0>;
>> + domain-performance-state = <&domain_perf_state2>;
>> + };
>>
>> Lets say leaky-device needs to switch on/off a gdsc and also send a
>> value to M3 to set a minimum performance state (so M3 configures the
>> voltage rails accordingly) how would it work?
>
> So the way I proposed this earlier is that every device will have a
> single power domain for it. In your case that power domain will
> represent gdscs. Idle state and performance state request will go to
> that level and then its up to the gdscs domain specific code to choose
> the right domain and its performance state. The parent domain shall
> then pass on the performance state to the next level power domain
> controlled by the M3 core.
>
> For example a device can have I power domain for idle state management
> and A power domain for active state management. The device will also
> have a M power domain which represents the gdscs. M can choose I or A
> as its parent. The power domain A (and similar power domains for all
> other devices) will have a parent power domain P. Now P is controlled
> or configured via the M3. Will that make sense ?

No, I am thoroughly confused :)
I was struggling with 2 powerdomains and now there are way too many of them :P

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