Hello, Some platforms have the capability to configure the performance state of their Power Domains. The performance levels are represented by positive integer values, a lower value represents lower performance state. We had some discussions about it in the past on the PM list [1], which is followed by discussions during the LPC. The outcome of all that was that we should extend Power Domain framework to support active state power management as well. The power-domains until now were only concentrating on the idle state management of the device and this needs to change in order to reuse the infrastructure of power domains for active state management. To get a complete picture of the proposed plan, following is what we need to do: - Create DT bindings to get domain performance state information for the platforms. - Enhance OPP framework to parse these and call into the PM Qos framework with a performance state request. - Enhance PM Qos framework to provide the API to be used by consumers (or OPP framework) and pass it on to the (Generic) Power Domain framework. - Enhance Generic Power Domain framework to accept such requests, accumulate all belonging to a single power domain and call domain driver specific callback with the performance state we want for the domain. - The domain driver shall then, in a platform specific way, set the requested performance level. - Note that these features are applicable to the CPU, GPU and other IIO or non-IIO devices. - There can be cases where a device can choose between multiple power domains based on what performance level we want for the device. In such cases, we should represent the multiplexer with a separate power domain. In effect, the device (or OPP table) will correspond to a single power domain, but the backend driver of that domain shall implement the multiplexing functionality. This patchset implements the very first part of this chain and introduces a new optional property for the consumers of the power-domains: domain-performance-state. This property can be used directly by the consumer or its OPP table. -- viresh [1] https://marc.info/?l=linux-pm&m=147747923708075&w=2 Viresh Kumar (2): PM / Domains: Introduce domain-performance-state binding PM / OPP: Introduce domain-performance-state binding to OPP nodes Documentation/devicetree/bindings/opp/opp.txt | 57 ++++++++++++++++++++++ .../devicetree/bindings/power/power_domain.txt | 6 +++ 2 files changed, 63 insertions(+) -- 2.7.1.410.g6faf27b -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
