linux-kernel - Re: [PATCH v3 1/6] dt-bindings: opp: Introduce opp-peak-KBps and opp-avg-KBps bindings

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Date:   Wed, 17 Jul 2019 13:24:48 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Saravana Kannan <saravanak@...gle.com>
Cc:     Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        vincent.guittot@...aro.org, seansw@....qualcomm.com,
        daidavid1@...eaurora.org, Rajendra Nayak <rnayak@...eaurora.org>,
        sibis@...eaurora.org, bjorn.andersson@...aro.org,
        evgreen@...omium.org, kernel-team@...roid.com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/6] dt-bindings: opp: Introduce opp-peak-KBps and
 opp-avg-KBps bindings

On 02-07-19, 18:10, Saravana Kannan wrote:
> Interconnects often quantify their performance points in terms of
> bandwidth. So, add opp-peak-KBps (required) and opp-avg-KBps (optional) to
> allow specifying Bandwidth OPP tables in DT.
> 
> opp-peak-KBps is a required property that replace opp-hz for Bandwidth OPP
> tables.
> 
> opp-avg-KBps is an optional property that can be used in Bandwidth OPP
> tables.
> 
> Signed-off-by: Saravana Kannan <saravanak@...gle.com>
> ---
>  Documentation/devicetree/bindings/opp/opp.txt | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
> index 76b6c79604a5..c869e87caa2a 100644
> --- a/Documentation/devicetree/bindings/opp/opp.txt
> +++ b/Documentation/devicetree/bindings/opp/opp.txt
> @@ -83,9 +83,14 @@ properties.
>  
>  Required properties:
>  - opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer. This is a
> -  required property for all device nodes but devices like power domains. The
> -  power domain nodes must have another (implementation dependent) property which
> -  uniquely identifies the OPP nodes.
> +  required property for all device nodes but for devices like power domains or
> +  bandwidth opp tables. The power domain nodes must have another (implementation
> +  dependent) property which uniquely identifies the OPP nodes. The interconnect
> +  opps are required to have the opp-peak-bw property.

                                   ??

> +
> +- opp-peak-KBps: Peak bandwidth in kilobytes per second, expressed as a 32-bit
> +  big-endian integer. This is a required property for all devices that don't
> +  have opp-hz. For example, bandwidth OPP tables for interconnect paths.
>  
>  Optional properties:
>  - opp-microvolt: voltage in micro Volts.
> @@ -132,6 +137,10 @@ Optional properties:
>  - opp-level: A value representing the performance level of the device,
>    expressed as a 32-bit integer.
>  
> +- opp-avg-KBps: Average bandwidth in kilobytes per second, expressed as a
> +  32-bit big-endian integer. This property is only meaningful in OPP tables
> +  where opp-peak-KBps is present.
> +
>  - clock-latency-ns: Specifies the maximum possible transition latency (in
>    nanoseconds) for switching to this OPP from any other OPP.
>  
> -- 
> 2.22.0.410.gd8fdbe21b5-goog

-- 
viresh