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Diffstat (limited to 'kernel/Documentation/devicetree/bindings/opp')
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diff --git a/kernel/Documentation/devicetree/bindings/opp/opp.txt b/kernel/Documentation/devicetree/bindings/opp/opp.txt new file mode 100644 index 000000000..0cb44dc21 --- /dev/null +++ b/kernel/Documentation/devicetree/bindings/opp/opp.txt @@ -0,0 +1,465 @@ +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-kHz vol-uV>. + 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. + +Devices may want to choose OPP tables at runtime and so can provide a list of +phandles here. But only *one* of them should be chosen at runtime. This must be +accompanied by a corresponding "operating-points-names" property, to uniquely +identify the OPP tables. + +If required, this can be extended for SoC vendor specfic bindings. Such bindings +should be documented as Documentation/devicetree/bindings/power/<vendor>-opp.txt +and should have a compatible description like: "operating-points-v2-<vendor>". + +Optional properties: +- operating-points-names: Names of OPP tables (required if multiple OPP + tables are present), to uniquely identify them. The same list must be present + for all the CPUs which are sharing clock/voltage rails and hence the OPP + tables. + +* 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. + +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 <target min max> + voltages. + + Entries for multiple regulators must be present in the same order as + regulators are specified in device's DT node. + +- 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 must be present in the same order as + regulators are specified in device's DT node. If this property isn't required + for few regulators, then this should be marked as zero for them. If it isn't + required for any regulator, then this property need not be present. + +- 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. Only one OPP in + the table should have this. + +- status: Marks the node enabled/disabled. + +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; + + opp00 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <970000 975000 985000>; + opp-microamp = <70000>; + clock-latency-ns = <300000>; + opp-suspend; + }; + opp01 { + opp-hz = /bits/ 64 <1100000000>; + opp-microvolt = <980000 1000000 1010000>; + opp-microamp = <80000>; + clock-latency-ns = <310000>; + }; + opp02 { + 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. + */ + + opp00 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <970000 975000 985000>; + opp-microamp = <70000>; + clock-latency-ns = <300000>; + opp-suspend; + }; + opp01 { + opp-hz = /bits/ 64 <1100000000>; + opp-microvolt = <980000 1000000 1010000>; + opp-microamp = <80000>; + clock-latency-ns = <310000>; + }; + opp02 { + 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; + + opp00 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <970000 975000 985000>; + opp-microamp = <70000>; + clock-latency-ns = <300000>; + opp-suspend; + }; + opp01 { + opp-hz = /bits/ 64 <1100000000>; + opp-microvolt = <980000 1000000 1010000>; + opp-microamp = <80000>; + clock-latency-ns = <310000>; + }; + opp02 { + 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; + + opp10 { + opp-hz = /bits/ 64 <1300000000>; + opp-microvolt = <1045000 1050000 1055000>; + opp-microamp = <95000>; + clock-latency-ns = <400000>; + opp-suspend; + }; + opp11 { + opp-hz = /bits/ 64 <1400000000>; + opp-microvolt = <1075000>; + opp-microamp = <100000>; + clock-latency-ns = <400000>; + }; + opp12 { + opp-hz = /bits/ 64 <1500000000>; + opp-microvolt = <1010000 1100000 1110000>; + opp-microamp = <95000>; + clock-latency-ns = <400000>; + turbo-mode; + }; + }; +}; + +Example 4: Handling multiple regulators + +/ { + cpus { + cpu@0 { + compatible = "arm,cortex-a7"; + ... + + cpu-supply = <&cpu_supply0>, <&cpu_supply1>, <&cpu_supply2>; + operating-points-v2 = <&cpu0_opp_table>; + }; + }; + + cpu0_opp_table: opp_table0 { + compatible = "operating-points-v2"; + opp-shared; + + opp00 { + 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 */ + + opp00 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <970000 975000 985000>, /* Supply 0 */ + <960000 965000 975000>, /* Supply 1 */ + <960000 965000 975000>; /* Supply 2 */ + opp-microamp = <70000>, /* Supply 0 */ + <70000>, /* Supply 1 */ + <70000>; /* Supply 2 */ + clock-latency-ns = <300000>; + }; + + /* OR */ + + opp00 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <970000 975000 985000>, /* Supply 0 */ + <960000 965000 975000>, /* Supply 1 */ + <960000 965000 975000>; /* Supply 2 */ + opp-microamp = <70000>, /* Supply 0 */ + <0>, /* Supply 1 doesn't need this */ + <70000>; /* Supply 2 */ + clock-latency-ns = <300000>; + }; + }; +}; + +Example 5: Multiple OPP tables + +/ { + cpus { + cpu@0 { + compatible = "arm,cortex-a7"; + ... + + cpu-supply = <&cpu_supply> + operating-points-v2 = <&cpu0_opp_table_slow>, <&cpu0_opp_table_fast>; + operating-points-names = "slow", "fast"; + }; + }; + + cpu0_opp_table_slow: opp_table_slow { + compatible = "operating-points-v2"; + status = "okay"; + opp-shared; + + opp00 { + opp-hz = /bits/ 64 <600000000>; + ... + }; + + opp01 { + opp-hz = /bits/ 64 <800000000>; + ... + }; + }; + + cpu0_opp_table_fast: opp_table_fast { + compatible = "operating-points-v2"; + status = "okay"; + opp-shared; + + opp10 { + opp-hz = /bits/ 64 <1000000000>; + ... + }; + + opp11 { + opp-hz = /bits/ 64 <1100000000>; + ... + }; + }; +}; |