PM / OPP: Add "opp-supported-hw" binding

[firefly-linux-kernel-4.4.55.git] / Documentation / devicetree / bindings / opp / opp.txt

diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
index 0cb44dc21f97ca7cfde5056ce7d44941d3439546..d072fa0ffbd44ca29486d91889a70ad1862dd132 100644 (file)
--- a/Documentation/devicetree/bindings/opp/opp.txt
+++ b/Documentation/devicetree/bindings/opp/opp.txt
@@ -123,6 +123,26 @@ Optional properties:
 - 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 <X Y Z>, 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. <X Y Z1 Z2> 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.
@@ -463,3 +483,48 @@ Example 5: Multiple OPP tables
                };
        };
 };
+
+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>;
+                       ...
+               };
+       };
+};