Many platforms require to switch to a intermediate frequency before
switching to a final frequency. Or they can switch to only particular
OPPs from any OPP.
For these add another property in OPP-v2, 'opp-next'.
Refer to the bindings for more details.
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
Documentation/devicetree/bindings/power/opp.txt | 130 ++++++++++++++++++++++++
1 file changed, 130 insertions(+)
diff --git a/Documentation/devicetree/bindings/power/opp.txt b/Documentation/devicetree/bindings/power/opp.txt
index 07959903ec32..c96dc77121b7 100644
--- a/Documentation/devicetree/bindings/power/opp.txt
+++ b/Documentation/devicetree/bindings/power/opp.txt
@@ -72,6 +72,9 @@ properties.
- clock-latency-ns: Specifies the maximum possible transition latency (in
nanoseconds) for switching to this OPP from any other OPP.
+- opp-next: It contains a list of phandles to other OPPs, to which we can switch
+ directly from this OPP (Explained later with examples). Missing property means
+ no restriction on switching to other OPPs.
- turbo-mode: Marks the OPP to be used only for turbo modes.
- status: Marks the node enabled/disabled.
@@ -363,6 +366,133 @@ Example 4: Handling multiple regulators
};
};
+Example 5: How to use "opp-next" property ?
+
+1.) Switch to a intermediate OPP (entry00) before switching to any other OPP.
+
+/ {
+ 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";
+ opp-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cpu0_opp>;
+ };
+ };
+
+ cpu0_opp: opp0 {
+ compatible = "operating-points-v2";
+ shared-opp;
+
+ opp_next: entry00 {
+ opp-khz = <500000>;
+ opp-microvolt = <800000>;
+ clock-latency-ns = <300000>;
+ /* Can switch to any OPP from here */
+ };
+ entry01 {
+ opp-khz = <600000>;
+ opp-microvolt = <800000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next>;
+ };
+ entry02 {
+ opp-khz = <900000>;
+ opp-microvolt = <970000 975000 985000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next>;
+ };
+ entry03 {
+ opp-khz = <1000000>;
+ opp-microvolt = <970000 975000 985000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next>;
+ };
+ entry04 {
+ opp-khz = <1100000>;
+ opp-microvolt = <980000 1000000 1010000>;
+ clock-latency-ns = <310000>;
+ opp-next = <&opp_next>;
+ };
+ entry05 {
+ opp-khz = <1200000>;
+ opp-microvolt = <1025000>;
+ clock-latency-ns = <290000>;
+ opp-next = <&opp_next>;
+ turbo-mode;
+ };
+ };
+};
+
+2.) Can only switch to the next or previous OPP directly.
+
+/ {
+ 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";
+ opp-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cpu0_opp>;
+ };
+ };
+
+ cpu0_opp: opp0 {
+ compatible = "operating-points-v2";
+ shared-opp;
+
+ opp_next0: entry00 {
+ opp-khz = <500000>;
+ opp-microvolt = <800000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next1>;
+ };
+ opp_next1: entry01 {
+ opp-khz = <600000>;
+ opp-microvolt = <800000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next0>, <&opp_next2>;
+ };
+ opp_next2: entry02 {
+ opp-khz = <900000>;
+ opp-microvolt = <970000 975000 985000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next1>, <&opp_next3>;
+ };
+ opp_next3: entry03 {
+ opp-khz = <1000000>;
+ opp-microvolt = <970000 975000 985000>;
+ clock-latency-ns = <300000>;
+ opp-next = <&opp_next2>, <&opp_next4>;
+ };
+ opp_next4: entry04 {
+ opp-khz = <1100000>;
+ opp-microvolt = <980000 1000000 1010000>;
+ clock-latency-ns = <310000>;
+ opp-next = <&opp_next3>, <&opp_next5>;
+ };
+ opp_next5: entry05 {
+ opp-khz = <1200000>;
+ opp-microvolt = <1025000>;
+ clock-latency-ns = <290000>;
+ opp-next = <&opp_next4>;
+ turbo-mode;
+ };
+ };
+};
+
+
Deprecated Bindings
-------------------
--
2.3.0.rc0.44.ga94655d
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