--- zzzz-none-000/linux-4.4.271/Documentation/devicetree/bindings/opp/opp.txt 2021-06-03 06:22:09.000000000 +0000 +++ maple-fsgw-759/linux-4.4.271/Documentation/devicetree/bindings/opp/opp.txt 2023-12-20 10:36:58.000000000 +0000 @@ -123,6 +123,26 @@ - opp-suspend: Marks the OPP to be used during device suspend. Only one OPP in the table should have this. +- 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 an 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. Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. @@ -462,4 +482,49 @@ ... }; }; +}; + +Example 6: 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"; + status = "okay"; + opp-shared; + + opp00 { + /* + * 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 = <900000 915000 925000>; + ... + }; + + opp01 { + /* + * 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 = <900000 915000 925000>; + ... + }; + }; };