Re: [PATCH V4 1/9] PM / OPP: Allow OPP table to be used for power-domains

From: Mark Brown
Date: Wed Apr 26 2017 - 09:56:24 EST


On Wed, Apr 26, 2017 at 10:02:39AM +0530, Rajendra Nayak wrote:
> > On 17/04/17 06:27, Viresh Kumar wrote:

> >>> If we are looking this power-domains with performance as just some
> >>> *advanced regulators*, I don't like the complexity added.

> + Mark

> I don;t see any public discussions on why we ruled out using regulators to
> support this but maybe there were some offline discussions on this.

> Mark, this is a long thread, so just summarizing here to give you the context.

> 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
> (or performance levels) they need by passing an integer value to the M3 (not actual
> voltage values). Since that didn't fit well with the existing regulator apis it was

As I'm getting fed up of saying: if the values you are setting are not
voltages and do not behave like voltages then the hardware should not be
represented as a voltage regulator since if they are represented as
voltage regulators things will expect to be able to control them as
voltage regulators. This hardware is quite clearly providing OPPs
directly, I would expect this to be handled in the OPP code somehow.

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