Generic OPP (Operating Performance Points) Bindings ---------------------------------------------------- Devices work at voltage-current-frequency combinations and some implementations have the liberty of choosing these. These combinations are called Operating Performance Points aka OPPs. This document defines bindings for these OPPs applicable across wide range of devices. For illustration purpose, this document uses CPU as a device. This document contain multiple versions of OPP binding and only one of them should be used per device. Binding 1: operating-points ============================ This binding only supports voltage-frequency pairs. Properties: - operating-points: An array of 2-tuples items, and each item consists of frequency and voltage like . freq: clock frequency in kHz vol: voltage in microvolt Examples: cpu@0 { compatible = "arm,cortex-a9"; reg = <0>; next-level-cache = <&L2>; operating-points = < /* kHz uV */ 792000 1100000 396000 950000 198000 850000 >; }; Binding 2: operating-points-v2 ============================ * Property: operating-points-v2 Devices supporting OPPs must set their "operating-points-v2" property with phandle to a OPP table in their DT node. The OPP core will use this phandle to find the operating points for the device. This can contain more than one phandle for power domain providers that provide multiple power domains. That is, one phandle for each power domain. If only one phandle is available, then the same OPP table will be used for all power domains provided by the power domain provider. If required, this can be extended for SoC vendor specific bindings. Such bindings should be documented as Documentation/devicetree/bindings/power/-opp.txt and should have a compatible description like: "operating-points-v2-". * OPP Table Node This describes the OPPs belonging to a device. This node can have following properties: Required properties: - compatible: Allow OPPs to express their compatibility. It should be: "operating-points-v2". - OPP nodes: One or more OPP nodes describing voltage-current-frequency combinations. Their name isn't significant but their phandle can be used to reference an OPP. Optional properties: - opp-shared: Indicates that device nodes using this OPP Table Node's phandle switch their DVFS state together, i.e. they share clock/voltage/current lines. Missing property means devices have independent clock/voltage/current lines, but they share OPP tables. - status: Marks the OPP table enabled/disabled. * OPP Node This defines voltage-current-frequency combinations along with other related properties. Required properties: - opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer. This is a required property for all device nodes but devices like power domains. The power domain nodes must have another (implementation dependent) property which uniquely identifies the OPP nodes. Optional properties: - opp-microvolt: voltage in micro Volts. A single regulator's voltage is specified with an array of size one or three. Single entry is for target voltage and three entries are for voltages. Entries for multiple regulators shall be provided in the same field separated by angular brackets <>. The OPP binding doesn't provide any provisions to relate the values to their power supplies or the order in which the supplies need to be configured and that is left for the implementation specific binding. Entries for all regulators shall be of the same size, i.e. either all use a single value or triplets. - opp-microvolt-: Named opp-microvolt property. This is exactly similar to the above opp-microvolt property, but allows multiple voltage ranges to be provided for the same OPP. At runtime, the platform can pick a and matching opp-microvolt- property will be enabled for all OPPs. If the platform doesn't pick a specific or the doesn't match with any opp-microvolt- properties, then opp-microvolt property shall be used, if present. - opp-microamp: The maximum current drawn by the device in microamperes considering system specific parameters (such as transients, process, aging, maximum operating temperature range etc.) as necessary. This may be used to set the most efficient regulator operating mode. Should only be set if opp-microvolt is set for the OPP. Entries for multiple regulators shall be provided in the same field separated by angular brackets <>. If current values aren't required for a regulator, then it shall be filled with 0. If current values aren't required for any of the regulators, then this field is not required. The OPP binding doesn't provide any provisions to relate the values to their power supplies or the order in which the supplies need to be configured and that is left for the implementation specific binding. - opp-microamp-: Named opp-microamp property. Similar to opp-microvolt- property, but for microamp instead. - opp-level: A value representing the performance level of the device, expressed as a 32-bit integer. - clock-latency-ns: Specifies the maximum possible transition latency (in nanoseconds) for switching to this OPP from any other OPP. - turbo-mode: Marks the OPP to be used only for turbo modes. Turbo mode is available on some platforms, where the device can run over its operating frequency for a short duration of time limited by the device's power, current and thermal limits. - opp-suspend: Marks the OPP to be used during device suspend. If multiple OPPs in the table have this, the OPP with highest opp-hz will be used. - opp-supported-hw: This enables us to select only a subset of OPPs from the larger OPP table, based on what version of the hardware we are running on. We still can't have multiple nodes with the same opp-hz value in OPP table. It's a user defined array containing a hierarchy of hardware version numbers, supported by the OPP. For example: a platform with hierarchy of three levels of versions (A, B and C), this field should be like , where X corresponds to Version hierarchy A, Y corresponds to version hierarchy B and Z corresponds to version hierarchy C. Each level of hierarchy is represented by a 32 bit value, and so there can be only 32 different supported version per hierarchy. i.e. 1 bit per version. A value of 0xFFFFFFFF will enable the OPP for all versions for that hierarchy level. And a value of 0x00000000 will disable the OPP completely, and so we never want that to happen. If 32 values aren't sufficient for a version hierarchy, than that version hierarchy can be contained in multiple 32 bit values. i.e. in the above example, Z1 & Z2 refer to the version hierarchy Z. - status: Marks the node enabled/disabled. - required-opps: This contains phandle to an OPP node in another device's OPP table. It may contain an array of phandles, where each phandle points to an OPP of a different device. It should not contain multiple phandles to the OPP nodes in the same OPP table. This specifies the minimum required OPP of the device(s), whose OPP's phandle is present in this property, for the functioning of the current device at the current OPP (where this property is present). Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / { cpus { #address-cells = <1>; #size-cells = <0>; cpu@0 { compatible = "arm,cortex-a9"; reg = <0>; next-level-cache = <&L2>; clocks = <&clk_controller 0>; clock-names = "cpu"; cpu-supply = <&cpu_supply0>; operating-points-v2 = <&cpu0_opp_table>; }; cpu@1 { compatible = "arm,cortex-a9"; reg = <1>; next-level-cache = <&L2>; clocks = <&clk_controller 0>; clock-names = "cpu"; cpu-supply = <&cpu_supply0>; operating-points-v2 = <&cpu0_opp_table>; }; }; cpu0_opp_table: opp_table0 { compatible = "operating-points-v2"; opp-shared; opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <975000 970000 985000>; opp-microamp = <70000>; clock-latency-ns = <300000>; opp-suspend; }; opp-1100000000 { opp-hz = /bits/ 64 <1100000000>; opp-microvolt = <1000000 980000 1010000>; opp-microamp = <80000>; clock-latency-ns = <310000>; }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <1025000>; clock-latency-ns = <290000>; turbo-mode; }; }; }; Example 2: Single cluster, Quad-core Qualcom-krait, switches DVFS states independently. / { cpus { #address-cells = <1>; #size-cells = <0>; cpu@0 { compatible = "qcom,krait"; reg = <0>; next-level-cache = <&L2>; clocks = <&clk_controller 0>; clock-names = "cpu"; cpu-supply = <&cpu_supply0>; operating-points-v2 = <&cpu_opp_table>; }; cpu@1 { compatible = "qcom,krait"; reg = <1>; next-level-cache = <&L2>; clocks = <&clk_controller 1>; clock-names = "cpu"; cpu-supply = <&cpu_supply1>; operating-points-v2 = <&cpu_opp_table>; }; cpu@2 { compatible = "qcom,krait"; reg = <2>; next-level-cache = <&L2>; clocks = <&clk_controller 2>; clock-names = "cpu"; cpu-supply = <&cpu_supply2>; operating-points-v2 = <&cpu_opp_table>; }; cpu@3 { compatible = "qcom,krait"; reg = <3>; next-level-cache = <&L2>; clocks = <&clk_controller 3>; clock-names = "cpu"; cpu-supply = <&cpu_supply3>; operating-points-v2 = <&cpu_opp_table>; }; }; cpu_opp_table: opp_table { compatible = "operating-points-v2"; /* * Missing opp-shared property means CPUs switch DVFS states * independently. */ opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <975000 970000 985000>; opp-microamp = <70000>; clock-latency-ns = <300000>; opp-suspend; }; opp-1100000000 { opp-hz = /bits/ 64 <1100000000>; opp-microvolt = <1000000 980000 1010000>; opp-microamp = <80000>; clock-latency-ns = <310000>; }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <1025000>; opp-microamp = <90000; lock-latency-ns = <290000>; turbo-mode; }; }; }; Example 3: Dual-cluster, Dual-core per cluster. CPUs within a cluster switch DVFS state together. / { cpus { #address-cells = <1>; #size-cells = <0>; cpu@0 { compatible = "arm,cortex-a7"; reg = <0>; next-level-cache = <&L2>; clocks = <&clk_controller 0>; clock-names = "cpu"; cpu-supply = <&cpu_supply0>; operating-points-v2 = <&cluster0_opp>; }; cpu@1 { compatible = "arm,cortex-a7"; reg = <1>; next-level-cache = <&L2>; clocks = <&clk_controller 0>; clock-names = "cpu"; cpu-supply = <&cpu_supply0>; operating-points-v2 = <&cluster0_opp>; }; cpu@100 { compatible = "arm,cortex-a15"; reg = <100>; next-level-cache = <&L2>; clocks = <&clk_controller 1>; clock-names = "cpu"; cpu-supply = <&cpu_supply1>; operating-points-v2 = <&cluster1_opp>; }; cpu@101 { compatible = "arm,cortex-a15"; reg = <101>; next-level-cache = <&L2>; clocks = <&clk_controller 1>; clock-names = "cpu"; cpu-supply = <&cpu_supply1>; operating-points-v2 = <&cluster1_opp>; }; }; cluster0_opp: opp_table0 { compatible = "operating-points-v2"; opp-shared; opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <975000 970000 985000>; opp-microamp = <70000>; clock-latency-ns = <300000>; opp-suspend; }; opp-1100000000 { opp-hz = /bits/ 64 <1100000000>; opp-microvolt = <1000000 980000 1010000>; opp-microamp = <80000>; clock-latency-ns = <310000>; }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <1025000>; opp-microamp = <90000>; clock-latency-ns = <290000>; turbo-mode; }; }; cluster1_opp: opp_table1 { compatible = "operating-points-v2"; opp-shared; opp-1300000000 { opp-hz = /bits/ 64 <1300000000>; opp-microvolt = <1050000 1045000 1055000>; opp-microamp = <95000>; clock-latency-ns = <400000>; opp-suspend; }; opp-1400000000 { opp-hz = /bits/ 64 <1400000000>; opp-microvolt = <1075000>; opp-microamp = <100000>; clock-latency-ns = <400000>; }; opp-1500000000 { opp-hz = /bits/ 64 <1500000000>; opp-microvolt = <1100000 1010000 1110000>; opp-microamp = <95000>; clock-latency-ns = <400000>; turbo-mode; }; }; }; Example 4: Handling multiple regulators / { cpus { cpu@0 { compatible = "vendor,cpu-type"; ... vcc0-supply = <&cpu_supply0>; vcc1-supply = <&cpu_supply1>; vcc2-supply = <&cpu_supply2>; operating-points-v2 = <&cpu0_opp_table>; }; }; cpu0_opp_table: opp_table0 { compatible = "operating-points-v2"; opp-shared; opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <970000>, /* Supply 0 */ <960000>, /* Supply 1 */ <960000>; /* Supply 2 */ opp-microamp = <70000>, /* Supply 0 */ <70000>, /* Supply 1 */ <70000>; /* Supply 2 */ clock-latency-ns = <300000>; }; /* OR */ opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <975000 970000 985000>, /* Supply 0 */ <965000 960000 975000>, /* Supply 1 */ <965000 960000 975000>; /* Supply 2 */ opp-microamp = <70000>, /* Supply 0 */ <70000>, /* Supply 1 */ <70000>; /* Supply 2 */ clock-latency-ns = <300000>; }; /* OR */ opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <975000 970000 985000>, /* Supply 0 */ <965000 960000 975000>, /* Supply 1 */ <965000 960000 975000>; /* Supply 2 */ opp-microamp = <70000>, /* Supply 0 */ <0>, /* Supply 1 doesn't need this */ <70000>; /* Supply 2 */ clock-latency-ns = <300000>; }; }; }; Example 5: opp-supported-hw (example: three level hierarchy of versions: cuts, substrate and process) / { cpus { cpu@0 { compatible = "arm,cortex-a7"; ... cpu-supply = <&cpu_supply> operating-points-v2 = <&cpu0_opp_table_slow>; }; }; opp_table { compatible = "operating-points-v2"; opp-shared; opp-600000000 { /* * Supports all substrate and process versions for 0xF * cuts, i.e. only first four cuts. */ opp-supported-hw = <0xF 0xFFFFFFFF 0xFFFFFFFF> opp-hz = /bits/ 64 <600000000>; opp-microvolt = <915000 900000 925000>; ... }; opp-800000000 { /* * Supports: * - cuts: only one, 6th cut (represented by 6th bit). * - substrate: supports 16 different substrate versions * - process: supports 9 different process versions */ opp-supported-hw = <0x20 0xff0000ff 0x0000f4f0> opp-hz = /bits/ 64 <800000000>; opp-microvolt = <915000 900000 925000>; ... }; }; }; Example 6: opp-microvolt-, opp-microamp-: (example: device with two possible microvolt ranges: slow and fast) / { cpus { cpu@0 { compatible = "arm,cortex-a7"; ... operating-points-v2 = <&cpu0_opp_table>; }; }; cpu0_opp_table: opp_table0 { compatible = "operating-points-v2"; opp-shared; opp-1000000000 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt-slow = <915000 900000 925000>; opp-microvolt-fast = <975000 970000 985000>; opp-microamp-slow = <70000>; opp-microamp-fast = <71000>; }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt-slow = <915000 900000 925000>, /* Supply vcc0 */ <925000 910000 935000>; /* Supply vcc1 */ opp-microvolt-fast = <975000 970000 985000>, /* Supply vcc0 */ <965000 960000 975000>; /* Supply vcc1 */ opp-microamp = <70000>; /* Will be used for both slow/fast */ }; }; };