Hi, On Thu, May 27, 2021 at 11:42:27AM +0530, Rajendra Nayak 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: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx> > --- > .../devicetree/bindings/power/power-domain.yaml | 50 ++++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml > index aed51e9..88cebf2 100644 > --- a/Documentation/devicetree/bindings/power/power-domain.yaml > +++ b/Documentation/devicetree/bindings/power/power-domain.yaml > @@ -66,6 +66,19 @@ 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 typically > + would also run off a fixed clock and not support dynamically scaling the > + 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. Each cell corresponds to one power-domain. > + A value of 0 can be used for power-domains with no performance state > + requirement. In case the power-domains have OPP tables associated, the values > + here would typically match with one of the entries in the OPP table. > + Is it just me or is this actually in the wrong place here? Given that #power-domain-cells is required this looks like the bindings for power domain providers, not consumers. :) It looks like the consumer bindings are still in Documentation/devicetree/bindings/power/power_domain.txt > required: > - "#power-domain-cells" > > @@ -131,3 +144,40 @@ 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>; > + }; Bjorn already asked this in v1 [1]: > May I ask how this is different from saying something like: > > required-opps = <&??>, <&rpmpd_opp_svs>; and maybe this was already discussed further elsewhere. But I think at the very least we need some clarification in the commit message + the binding documentation how your new property relates to the existing "required-opps" binding. Because even if it might not be implemented at the moment, Documentation/devicetree/bindings/power/power_domain.txt actually also specifies "required-opps" for device nodes e.g. with the following example: leaky-device0@12350000 { compatible = "foo,i-leak-current"; reg = <0x12350000 0x1000>; power-domains = <&power 0>; required-opps = <&domain0_opp_0>; }; It looks like Viresh added that in commit e856f078bcf1 ("OPP: Introduce "required-opp" property"). And in general I think it's a bit inconsistent that we usually refer to performance states with phandles into the OPP table, but the assigned-performance-states suddenly use "raw numbers". Stephan [1]: https://lore.kernel.org/linux-arm-msm/YAG%2FpNXQOS+C2zLr@xxxxxxxxxxx/