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

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Message-ID: <20170410092515.GF24555@vireshk-i7>
Date:   Mon, 10 Apr 2017 14:55:15 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rob Herring <robh@...nel.org>
Cc:     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>,
        lina.iyer@...aro.org, rnayak@...eaurora.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH V4 1/9] PM / OPP: Allow OPP table to be used for
 power-domains

On 24-03-17, 10:44, Rob Herring wrote:
> On Mon, Mar 20, 2017 at 03:02:13PM +0530, Viresh Kumar wrote:
> > Power-domains need to express their active states in DT and what's
> > better than OPP table for that.
> > 
> > This patch allows power-domains to reuse OPP tables to express their
> > active states. The "opp-hz" property isn't a required property anymore
> > as power-domains may not always use them.
> 
> Then maybe you shouldn't be trying to make OPP table work here. At that 
> point you just need a table of voltage(s) per performance state?

Because that's what Kevin strongly recommended in the previous
versions.

@Kevin: Would you like to reply here ?

> > Add a new property "domain-performance-state", which will contain
> > positive integer values to represent performance levels of the
> > power-domains as described in this patch.
> 
> Why not reference the OPP entries from the domain:
> 
> performance-states = <&opp1>, <&opp2>;

Because that would require additional code in the OPP core to parse
these then. Right now it is quite straight forward with the bindings I
presented.

> Just thinking out loud, not saying that is what you should do. The 
> continual evolution of power (management) domain, idle state, and OPP 
> bindings is getting tiring.

I agree :)

-- 
viresh