On some platforms (Like Qualcomm's SoCs), it is not decided until runtime on what OPPs to use. The OPP tables can be fixed at compile time, but which table to use is found out only after reading some efuses (sort of an prom) and knowing characteristics of the SoC.
To support such platform we need to pass multiple OPP tables per device and hardware should be able to choose one and only one table out of those.
Update OPP-v2 bindings to support that.
Acked-by: Nishanth Menon nm@ti.com Reviewed-by: Stephen Boyd sboyd@codeaurora.org Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- Documentation/devicetree/bindings/power/opp.txt | 52 +++++++++++++++++++++++++ 1 file changed, 52 insertions(+)
diff --git a/Documentation/devicetree/bindings/power/opp.txt b/Documentation/devicetree/bindings/power/opp.txt index 0ca96e73d2a3..f6f75545149e 100644 --- a/Documentation/devicetree/bindings/power/opp.txt +++ b/Documentation/devicetree/bindings/power/opp.txt @@ -45,6 +45,9 @@ 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. + 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>". @@ -63,6 +66,9 @@ This describes the OPPs belonging to a device. This node can have following reference an OPP.
Optional properties: +- opp-name: Name of the OPP table, to uniquely identify it if more than one OPP + table is supplied in "operating-points-v2" property of device. + - 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, @@ -396,3 +402,49 @@ Example 4: Handling multiple regulators }; }; }; + +Example 5: Multiple OPP tables + +/ { + cpus { + cpu@0 { + compatible = "arm,cortex-a7"; + ... + + opp-supply = <&cpu_supply> + operating-points-v2 = <&cpu0_opp_table_slow>, <&cpu0_opp_table_fast>; + }; + }; + + cpu0_opp_table_slow: opp_table_slow { + compatible = "operating-points-v2"; + opp-name = "slow"; + opp-shared; + + opp00 { + opp-hz = <600000000>; + ... + }; + + opp01 { + opp-hz = <800000000>; + ... + }; + }; + + cpu0_opp_table_fast: opp_table_fast { + compatible = "operating-points-v2"; + opp-name = "fast"; + opp-shared; + + opp10 { + opp-hz = <1000000000>; + ... + }; + + opp11 { + opp-hz = <1100000000>; + ... + }; + }; +};