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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Tue, 1 Jun 2021 12:33:31 +0200
Message-ID: <CAPDyKFprcA3DJW4bxef88oekpB5cNCkgy73_=mr40YWjNphvOw@mail.gmail.com>
Subject: Re: [PATCH v2 1/3] dt-bindings: power: Introduce 'assigned-performance-states'
 property
To:     Rajendra Nayak <rnayak@codeaurora.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Roja Rani Yarubandi <rojay@codeaurora.org>
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On Thu, 27 May 2021 at 08:13, Rajendra Nayak <rnayak@codeaurora.org> wrote:
>
> While most devices within power-domains which support performance states,
> scale the performance state dynamically, some devices might want to
> set a static/default performance state while the device is active.
> These devices typically would also run off a fixed clock and not support
> dynamically scaling the device's performance, also known as DVFS techniques.
> Add a property 'assigned-performance-states' which client devices can
> use to set this default performance state on their power-domains.
>
> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>

I don't have a strong opinion about using "default-performance-state"
or "assigned-performance-state". Although, perhaps people can relate
to the existing "assigned-clock-rates" DT binding?
In any case, please add:

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
>  .../devicetree/bindings/power/power-domain.yaml    | 50 ++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
> index aed51e9..88cebf2 100644
> --- a/Documentation/devicetree/bindings/power/power-domain.yaml
> +++ b/Documentation/devicetree/bindings/power/power-domain.yaml
> @@ -66,6 +66,19 @@ properties:
>        by the given provider should be subdomains of the domain specified
>        by this binding.
>
> +  assigned-performance-states:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    description:
> +       Some devices might need to configure their power domains in a default
> +       performance state while the device is active. These devices typically
> +       would also run off a fixed clock and not support dynamically scaling the
> +       device's performance, also known as DVFS techniques. The list of performance
> +       state values should correspond to the list of power domains specified as part
> +       of the power-domains property. Each cell corresponds to one power-domain.
> +       A value of 0 can be used for power-domains with no performance state
> +       requirement. In case the power-domains have OPP tables associated, the values
> +       here would typically match with one of the entries in the OPP table.
> +
>  required:
>    - "#power-domain-cells"
>
> @@ -131,3 +144,40 @@ examples:
>              min-residency-us = <7000>;
>          };
>      };
> +
> +  - |
> +    parent4: power-controller@12340000 {
> +        compatible = "foo,power-controller";
> +        reg = <0x12340000 0x1000>;
> +        #power-domain-cells = <0>;
> +    };
> +
> +    parent5: power-controller@43210000 {
> +        compatible = "foo,power-controller";
> +        reg = <0x43210000 0x1000>;
> +        #power-domain-cells = <0>;
> +        operating-points-v2 = <&power_opp_table>;
> +
> +        power_opp_table: opp-table {
> +            compatible = "operating-points-v2";
> +
> +            power_opp_low: opp1 {
> +                opp-level = <16>;
> +            };
> +
> +            rpmpd_opp_ret: opp2 {
> +                opp-level = <64>;
> +            };
> +
> +            rpmpd_opp_svs: opp3 {
> +                opp-level = <256>;
> +            };
> +        };
> +    };
> +
> +    child4: consumer@12341000 {
> +        compatible = "foo,consumer";
> +        reg = <0x12341000 0x1000>;
> +        power-domains = <&parent4>, <&parent5>;
> +        assigned-performance-states = <0>, <256>;
> +    };
> --
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