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

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(+)

On Thu, 24 Dec 2020 16:42:08 +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(+)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:
./Documentation/devicetree/bindings/power/power-domain.yaml:72:8: [warning] wrong indentation: expected 6 but found 7 (indentation)

dtschema/dtc warnings/errors:

See https://patchwork.ozlabs.org/patch/1420485

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

On Thu, 31 Dec 2020 at 16:49, Rob Herring <robh@kernel.org> wrote:
>
> 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'?

Right. Some SoCs already use the cell to specify per device SoC
specific data [1].

Although, I am wondering if we shouldn't consider
"assigned-performance-states" as a more generic binding. I think it
would be somewhat comparable with the existing "assigned-clock-rates"
binding, don't you think?

[...]

Kind regards
Uffe

[1]
Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt

On Thu 24 Dec 05:12 CST 2020, 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.
> +
>  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>;

May I ask how this is different from saying something like:

	required-opps = <&??>, <&rpmpd_opp_svs>:

Regards,
Bjorn

> +    };
> -- 
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