linux-kernel - Re: [PATCH V4 2/9] PM / Domains: Use OPP tables for power-domains

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Date:   Thu, 13 Apr 2017 11:33:42 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, ulf.hansson@...aro.org,
        Kevin Hilman <khilman@...aro.org>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Nishanth Menon <nm@...com>, robh+dt@...nel.org,
        lina.iyer@...aro.org, rnayak@...eaurora.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH V4 2/9] PM / Domains: Use OPP tables for power-domains

On 12-04-17, 17:58, Sudeep Holla wrote:
> 
> 
> On 20/03/17 09:32, Viresh Kumar wrote:
> > The OPP table bindings contains all the necessary fields to support
> > power-domains now. Update the power-domain bindings to allow
> > "operating-points-v2" to be present within the power-domain node.
> > 
> > Also allow consumer devices, that don't use OPP tables, to specify the
> > parent power-domain's performance level using the
> > "domain-performance-state" property.
> > 
> > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> > ---
> >  .../devicetree/bindings/power/power_domain.txt     | 42 ++++++++++++++++++++++
> >  1 file changed, 42 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> > index 723e1ad937da..5db112fa5d7c 100644
> > --- a/Documentation/devicetree/bindings/power/power_domain.txt
> > +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> > @@ -38,6 +38,9 @@ phandle arguments (so called PM domain specifiers) of length specified by the
> >    domain's idle states. In the absence of this property, the domain would be
> >    considered as capable of being powered-on or powered-off.
> >  
> > +- operating-points-v2 : This describes the performance states of a PM domain.
> > +  Refer to ../opp/opp.txt for more information.
> > +
> >  Example:
> >  
> >  	power: power-controller@...40000 {
> > @@ -118,4 +121,43 @@ The node above defines a typical PM domain consumer device, which is located
> >  inside a PM domain with index 0 of a power controller represented by a node
> >  with the label "power".
> >  
> > +Optional properties:
> > +- domain-performance-state: A positive integer value representing the minimum
> > +  power-domain performance level required by the consumer device. The integer
> > +  value '0' represents the lowest performance level and the higher values
> > +  represent higher performance levels. The value of "domain-performance-state"
> > +  field should match the "domain-performance-state" field of one of the OPP
> > +  nodes in the parent power-domain's OPP table.
> > +
> > +
> > +
> > +Example:
> > +
> > +	domain_opp_table: opp_table {
> > +		compatible = "operating-points-v2";
> > +
> > +		opp@1 {
> > +			domain-performance-state = <1>;
> > +			opp-microvolt = <975000 970000 985000>;
> > +		};
> > +		opp@2 {
> > +			domain-performance-state = <2>;
> > +			opp-microvolt = <1075000 1000000 1085000>;
> > +		};
> > +	};
> > +
> > +	parent: power-controller@...40000 {
> > +		compatible = "foo,power-controller";
> > +		reg = <0x12340000 0x1000>;
> > +		#power-domain-cells = <0>;
> > +		operating-points-v2 = <&domain_opp_table>;
> 
> As mentioned in the other email, it would be good to consider
> scalability with multiple power domains in a PM domain provider.
> i.e case of #power-domain-cells = <1> or more

Yeah, but that isn't supported for devices today. So no point
considering that today.

-- 
viresh