@@ -72,6 +72,9 @@ Optional properties:
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.
+ This optional property can be used without any OPP nodes when its only purpose
+ is to describe a dependency of clock/voltage/current lines among a set of
+ devices.
- status: Marks the OPP table enabled/disabled.
@@ -568,3 +571,53 @@ Example 6: opp-microvolt-<name>, opp-microamp-<name>:
};
};
};
+
+Example 7: Single cluster Quad-core ARM cortex A53, OPP points from firmware,
+distinct clock controls but two sets of clock/voltage/current lines.
+
+/ {
+ cpus {
+ #address-cells = <2>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "arm,cortex-a53";
+ reg = <0x0 0x100>;
+ next-level-cache = <&A53_L2>;
+ clocks = <&dvfs_controller 0>;
+ operating-points-v2 = <&cpu_opp0_table>;
+ };
+ cpu@1 {
+ compatible = "arm,cortex-a53";
+ reg = <0x0 0x101>;
+ next-level-cache = <&A53_L2>;
+ clocks = <&dvfs_controller 1>;
+ operating-points-v2 = <&cpu_opp0_table>;
+ };
+ cpu@2 {
+ compatible = "arm,cortex-a53";
+ reg = <0x0 0x102>;
+ next-level-cache = <&A53_L2>;
+ clocks = <&dvfs_controller 2>;
+ operating-points-v2 = <&cpu_opp1_table>;
+ };
+ cpu@3 {
+ compatible = "arm,cortex-a53";
+ reg = <0x0 0x103>;
+ next-level-cache = <&A53_L2>;
+ clocks = <&dvfs_controller 3>;
+ operating-points-v2 = <&cpu_opp1_table>;
+ };
+
+ };
+
+ cpu_opp0_table: opp0_table {
+ compatible = "operating-points-v2";
+ opp-shared;
+ };
+
+ cpu_opp1_table: opp1_table {
+ compatible = "operating-points-v2";
+ opp-shared;
+ };
+};
Currently the optional property opp-shared is used within an opp table to tell that a set of devices share their clock/voltage lines (and the opp points). It is therefore possible to use an empty opp table to convey only that information, useful in situations where the opp points are provided via other means (hardware. firmware, etc). Update the documentation to remark this additional case and provide an example. Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com> --- Documentation/devicetree/bindings/opp/opp.txt | 53 +++++++++++++++++++ 1 file changed, 53 insertions(+)