Re: [PATCH v3 1/2] PM / OPP: introduce an OPP power estimation helper

[Quentin Perret <quentin.perret@arm.com>]

On Friday 19 Jan 2018 at 15:36:42 (-0800), Joel Fernandes wrote:
> > +/**
> > + * Estimate the power of an OPP as P = C * V^2 * f, with C the device's
> > + * capacitance, V the OPP's voltage and f the OPP's frequency.
> > + */
> > +static void _opp_estimate_power(struct dev_pm_opp *opp, unsigned long cap)
> > +{
> > +       unsigned long mV = opp->supplies[0].u_volt / 1000;
> > +       unsigned long KHz = opp->rate / 1000;
> > +
> > +       opp->power_estimate_uw = cap * mV * mV * KHz / 1000000000;
> > +}
> > +
> >  /*
> >   * Returns:
> >   * 0: On success. And appropriate error message for duplicate OPPs.
> > @@ -1039,6 +1069,8 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
> >         if (opp_table->get_pstate)
> >                 new_opp->pstate = opp_table->get_pstate(dev, new_opp->rate);
> >
> > +       _opp_estimate_power(new_opp, opp_table->capacitance);
> > +
> 
> Does this need to be a separate static function? There's only one user
> of the function in the C file and it adds more LOC.

True, but I guess that makes sense conceptually to factor out this
feature. Maybe it's just my personal taste :)

> 
> Otherwise, feel free to add FWIW:
> Reviewed-by: Joel Fernandes <joelaf@google.com>

Cool, thank you very much !

Quentin