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authorViresh Kumar <viresh.kumar@linaro.org>2015-06-22 14:21:38 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-06-22 14:21:38 +0200
commita9a80e7e3177000344c3993411aada4d1e019f7c (patch)
tree2b7d0b80662ca6be8f8557ced444974aec0e3a53 /Documentation/devicetree
parentb901b518077ba87bc84c84de02fce186cf9e5856 (diff)
PM / OPP: Allow multiple OPP tables to be passed via DT
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 operating-points-v2 bindings to support that. Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/power/opp.txt60
1 files changed, 60 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/power/opp.txt b/Documentation/devicetree/bindings/power/opp.txt
index 259bf00edf7d..3d5d32ca0f97 100644
--- a/Documentation/devicetree/bindings/power/opp.txt
+++ b/Documentation/devicetree/bindings/power/opp.txt
@@ -45,10 +45,21 @@ 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
@@ -68,6 +79,8 @@ Optional properties:
Missing property means devices have independent clock/voltage/current lines,
but they share OPP tables.
+- status: Marks the OPP table enabled/disabled.
+
* OPP Node
@@ -396,3 +409,50 @@ Example 4: Handling multiple regulators
};
};
};
+
+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 = <600000000>;
+ ...
+ };
+
+ opp01 {
+ opp-hz = <800000000>;
+ ...
+ };
+ };
+
+ cpu0_opp_table_fast: opp_table_fast {
+ compatible = "operating-points-v2";
+ status = "okay";
+ opp-shared;
+
+ opp10 {
+ opp-hz = <1000000000>;
+ ...
+ };
+
+ opp11 {
+ opp-hz = <1100000000>;
+ ...
+ };
+ };
+};