linux-kernel - Re: [PATCH V2 2/5] PM / OPP: Add {opp-microvolt|opp-microamp|turbo-mode|opp-suspend}-<name> binding

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Message-ID: <20151105031913.GA29491@ubuntu>
Date:	Thu, 5 Nov 2015 08:49:13 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Rob Herring <robh@...nel.org>
Cc:	Rafael Wysocki <rjw@...ysocki.net>, robh+dt@...nel.org,
	sboyd@...eaurora.org, lee.jones@...aro.org,
	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	mark.rutland@....com, pawel.moll@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org, nm@...com,
	devicetree@...r.kernel.org, b.zolnierkie@...sung.com,
	m.szyprowski@...sung.com, open list <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH V2 2/5] PM / OPP: Add
 {opp-microvolt|opp-microamp|turbo-mode|opp-suspend}-<name> binding

On 04-11-15, 21:02, Rob Herring wrote:
> > +- turbo-mode-<name>: Named turbo-mode property. Similar to opp-microvolt-<name>
> > +  property, but for turbo mode instead.
> > +
> >  - opp-suspend: Marks the OPP to be used during device suspend. Only one OPP in
> >    the table should have this.
> >  
> > +- opp-suspend-<name>: Named opp-suspend property. Similar to
> > +  opp-microvolt-<name> property, but for suspend opp instead.
> > +
> 
> I don't think these last 2 make sense. turbo-mode is a flag that the 
> mode has restrictions such as other cores have to be idle or something. 
> Similarly, opp-suspend should not vary by <name>.

Based on what version of the hardware you are running, via
opp-supported-hw property, the platform can enable a different set of
OPPs. And in that case we may want to select different OPPs marked as
turbo or suspend freq. That's what I thought at least.

For example, on version A of the hardware we have following available
frequencies: 800, 1000, 1100, 1200 MHz. Where 800 MHz is the suspend
freq and 1200 is the turbo one.

But on a slightly different version of hardware B, we have two more
OPPs available: 700 and 1400 MHz. And in that case we want the suspend
freq to be 700 and turbo OPP to be only 1400 MHz.

-- 
viresh
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