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SubjectRe: [PATCH 1/3] dt-bindings: power: Introduce 'assigned-performance-states' property
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On 8/5/2020 12:09 PM, Stephen Boyd wrote:
> Quoting Rajendra Nayak (2020-08-04 04:46:54)
>> 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 of a fixed clock and not support
>
> s/of/off/
>
>> dyamically scaling the device's performance, also known as DVFS techniques.
>
> s/dyamically/dynamically/
>
>> 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>
>> ---
>> .../devicetree/bindings/power/power-domain.yaml | 47 ++++++++++++++++++++++
>> 1 file changed, 47 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
>> index ff5936e..48e9319 100644
>> --- a/Documentation/devicetree/bindings/power/power-domain.yaml
>> +++ b/Documentation/devicetree/bindings/power/power-domain.yaml
>> @@ -66,6 +66,16 @@ 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 of a fixed clock and not support dyamically scaling the
>
> Same of and dynamically comment.
>
>> + 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.
>
> This is different than assigned-clock-rates. I guess that's OK because
> we don't need to assign parents with more specifiers. Maybe it should be
> worded more strongly to clearly state that each cell corresponds to one
> power domain? And that it should match the opp-level inside any OPP
> table for the power domain?

Sure, I'll reword it to make it clear that we need the same number of cells
as power-domains, and as you pointed out below that 0 corresponds to not setting
anything.

For the matching of opp-level inside the OPP table of the power-domain, I don't
think from the power-domain bindings we limit providers with only OPP tables to
support performance states? It could be just a range that the provider manages
internally?

And thanks for catching all my typos :), I'll have them fixed when I re-spin.

>
>> +
>> required:
>> - "#power-domain-cells"
>>
>> @@ -129,3 +139,40 @@ 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>;
>
> I guess <0> means don't set anything?
>

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