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

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Message-ID: <6f72cb6e-2d8c-4e68-59cd-67f40e8c3118@arm.com>
Date:   Wed, 12 Apr 2017 17:58:41 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, ulf.hansson@...aro.org,
        Kevin Hilman <khilman@...aro.org>,
        Sudeep Holla <sudeep.holla@....com>,
        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 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

-- 
Regards,
Sudeep