On 28/04/17 06:00, Viresh Kumar wrote:
On 27-04-17, 16:20, Rajendra Nayak wrote:
On 04/27/2017 03:12 PM, Sudeep Holla wrote: []..
At qualcomm, we have an external M3 core (running its own firmware) which controls a few voltage rails (including AVS on those). The devices vote for the voltage levels
Thanks for explicitly mentioning this, but ...
(or performance levels) they need by passing an integer value to the M3 (not actual
you contradict here, is it just voltage or performance(i.e. frequency) or both ? We need clarity there to choose the right representation.
Its just voltage.
Right. Its just voltage in this case, but we can't speak of future platforms here and we have to consider this thing as an operating performance point only. I still think that this thread is moving in the right direction, specially after V6 which looks much better.
Just thinking out loud, I can see platforms with have OPPs can move to this binding in future eliminating the need to specify the clock and regulators explicitly. So, I am not saying I against this idea, but I see it might complicate the above case in terms of the precedence that we consider in DT from backward compatibility.
E.g. if you now use this for just regulators, then I assume you continue to use clocks. However, that makes it difficult for platforms implementing *real* OPPs to reuse this binding as they may expect to skip clock altogether.
Also we may need OPPs(both volt/freq), voltage only and clock only bindings though all 3 are driven by the firmware and all are at abstract levels. I am trying to broaden the scope now without having to churn this binding again in near future.
So I don't totally agree that voltage regulators much have *real* voltages and not abstract scale. Yes the correct bindings might have such restrictions but can't we extend it ?
Anyways these are just my opinion.
If we have anything strong against the way V6 is trying to solve it, I want to talk about it right now and get inputs from all the parties involved. Scrapping all this work is fine, but I would like to do it ASAP in that case :)
As I said I am not against it, but I see it useful for a different use-case, just not the one you are trying to solve here ;)