Re: [PATCH 1/3] dt-bindings: power: Introduce 'assigned-performance-states' property

Rob Herring
2020-12-31T15:50:29Z

On Thu, Dec 24, 2020 at 04:42:08PM +0530, Roja Rani Yarubandi 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: Roja Rani Yarubandi <rojay@codeaurora.org>
> ---
> .../bindings/power/power-domain.yaml | 49 +++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
> index aed51e9dcb11..a42977a82d06 100644
> --- a/Documentation/devicetree/bindings/power/power-domain.yaml
> +++ b/Documentation/devicetree/bindings/power/power-domain.yaml
> @@ -66,6 +66,18 @@ 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 typcially
> + would also run off a fixed clock and not support dynamically scaling
> + the device's performance, also known as DVFS techniques. Each cell in
> + performance state value corresponds to one power domain specified as
> + part of the power-domains property. Performance state value can be an
> + opp-level inside an OPP table of the power-domain and need not match
> + with any OPP table performance state.

Couldn't this just be an additional cell in 'power-domains'?

> +
> required:
> - "#power-domain-cells"
>
> @@ -131,3 +143,40 @@ 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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