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

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Date:   Fri, 28 Apr 2017 16:42:36 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     Rajendra Nayak <rnayak@...eaurora.org>,
        Mark Brown <broonie@...nel.org>,
        Rafael Wysocki <rjw@...ysocki.net>, ulf.hansson@...aro.org,
        Kevin Hilman <khilman@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        robh+dt@...nel.org, lina.iyer@...aro.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH V4 1/9] PM / OPP: Allow OPP table to be used for
 power-domains

On 28-04-17, 10:44, Sudeep Holla wrote:
> 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.

Everyone's opinion has equal merit here :)

I believe that some of your hesitation came from the point that I have
made opp-hz optional. That isn't the case anymore with V6.

Can we please take the discussion to that thread now and see if you
can find similar problems there as well.

Thanks a lot.

-- 
viresh