Re: [PATCH v7 1/7] dt-bindings: opp: Introduce opp-peak-kBps and opp-avg-kBps bindings

Viresh Kumar
2020-04-30T05:09:23Z

On 24-04-20, 18:53, Georgi Djakov wrote:
> From: Saravana Kannan <saravanak@google.com>
>
> 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 replaces 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@google.com>
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
> v7:
> * I have dropped Rob's Reviewed-by, because of the minor change below:
> * In order to store the bandwidth values for multiple paths, the
> opp-peak-kBps and opp-avg-kBps are now defined as arrays of integers,
> instead of just integers.
> * Improved wording (Viresh)
>
> v6: https://lore.kernel.org/r/20191207002424.201796-2-saravanak@google.com
>
> Documentation/devicetree/bindings/opp/opp.txt | 20 ++++++++++++++++---
> .../devicetree/bindings/property-units.txt | 4 ++++
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
> index 68592271461f..a8a6a3bfcfcb 100644
> --- a/Documentation/devicetree/bindings/opp/opp.txt
> +++ b/Documentation/devicetree/bindings/opp/opp.txt
> @@ -83,9 +83,17 @@ 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 except for devices like power domains
> + or bandwidth opp tables. The devices which don't have this property must have

bandwidth opp table ?

> + another (implementation dependent) property which uniquely identifies the OPP
> + nodes.
> +
> +
> +- opp-peak-kBps: Peak bandwidth in kilobytes per second, expressed as an array
> + of 32-bit big-endian integers. Each element of the array represents the
> + peak bandwidth value of each interconnect path. The number of elements should
> + match the number of interconnect paths. This is a required property for
> + bandwidth OPP tables.
>
> Optional properties:
> - opp-microvolt: voltage in micro Volts.
> @@ -132,6 +140,12 @@ 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 an array
> + of 32-bit big-endian integers. Each element of the array represents the
> + average bandwidth value of each interconnect path. The number of elements
> + should match the number of interconnect paths. 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.
>
> diff --git a/Documentation/devicetree/bindings/property-units.txt b/Documentation/devicetree/bindings/property-units.txt
> index e9b8360b3288..c80a110c1e26 100644
> --- a/Documentation/devicetree/bindings/property-units.txt
> +++ b/Documentation/devicetree/bindings/property-units.txt
> @@ -41,3 +41,7 @@ Temperature
> Pressure
> ----------------------------------------
> -kpascal : kilopascal
> +
> +Throughput
> +----------------------------------------
> +-kBps : kilobytes per second

--
viresh