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authorViresh Kumar <viresh.kumar@linaro.org>2015-11-11 08:10:55 +0530
committerAlex Shi <alex.shi@linaro.org>2016-04-01 13:24:13 +0800
commit84ee2366f5a391afd1a1024fc0438df09d979ace (patch)
tree1b920ab7cb628aed689c76a6b0384b21e0a931ca /Documentation
parent4a0b368adb397b991717213e317fc5dff57cac90 (diff)
downloadlinux-linaro-stable-84ee2366f5a391afd1a1024fc0438df09d979ace.tar.gz
PM / OPP: Add {opp-microvolt|opp-microamp}-<name> binding
Depending on the version of hardware or its properties, which are only known at runtime, various properties of the OPP can change. For example, an OPP with frequency 1.2 GHz, may have different voltage/current requirements based on the version of the hardware it is running on. In order to not replicate the same OPP tables for varying values of all such fields, this commit introduces the concept of opp-property-<name>. The <name> can be chosen by the platform at runtime, and OPPs will be initialized depending on that name string. Currently support is extended for the following properties: - opp-microvolt-<name> - opp-microamp-<name> If the name string isn't provided by the platform, or if it is provided but doesn't match the properties present in the OPP node, we will fall back to the original properties without the -<name> string, if they are available. Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> (cherry picked from commit ffdb8cc7a27c89175e541e68e2a73f1f63ab8c6b) Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/opp/opp.txt47
1 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
index 32bf3b984cad..50d02cac34e5 100644
--- a/Documentation/devicetree/bindings/opp/opp.txt
+++ b/Documentation/devicetree/bindings/opp/opp.txt
@@ -88,6 +88,14 @@ Optional properties:
Entries for multiple regulators must be present in the same order as
regulators are specified in device's DT node.
+- opp-microvolt-<name>: Named opp-microvolt property. This is exactly similar to
+ the above opp-microvolt property, but allows multiple voltage ranges to be
+ provided for the same OPP. At runtime, the platform can pick a <name> and
+ matching opp-microvolt-<name> property will be enabled for all OPPs. If the
+ platform doesn't pick a specific <name> or the <name> doesn't match with any
+ opp-microvolt-<name> properties, then opp-microvolt property shall be used, if
+ present.
+
- opp-microamp: The maximum current drawn by the device in microamperes
considering system specific parameters (such as transients, process, aging,
maximum operating temperature range etc.) as necessary. This may be used to
@@ -100,6 +108,9 @@ Optional properties:
for few regulators, then this should be marked as zero for them. If it isn't
required for any regulator, then this property need not be present.
+- opp-microamp-<name>: Named opp-microamp property. Similar to
+ opp-microvolt-<name> property, but for microamp instead.
+
- clock-latency-ns: Specifies the maximum possible transition latency (in
nanoseconds) for switching to this OPP from any other OPP.
@@ -516,3 +527,39 @@ Example 6: opp-supported-hw
};
};
};
+
+Example 7: opp-microvolt-<name>, opp-microamp-<name>:
+(example: device with two possible microvolt ranges: slow and fast)
+
+/ {
+ cpus {
+ cpu@0 {
+ compatible = "arm,cortex-a7";
+ ...
+
+ operating-points-v2 = <&cpu0_opp_table>;
+ };
+ };
+
+ cpu0_opp_table: opp_table0 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp00 {
+ opp-hz = /bits/ 64 <1000000000>;
+ opp-microvolt-slow = <900000 915000 925000>;
+ opp-microvolt-fast = <970000 975000 985000>;
+ opp-microamp-slow = <70000>;
+ opp-microamp-fast = <71000>;
+ };
+
+ opp01 {
+ opp-hz = /bits/ 64 <1200000000>;
+ opp-microvolt-slow = <900000 915000 925000>, /* Supply vcc0 */
+ <910000 925000 935000>; /* Supply vcc1 */
+ opp-microvolt-fast = <970000 975000 985000>, /* Supply vcc0 */
+ <960000 965000 975000>; /* Supply vcc1 */
+ opp-microamp = <70000>; /* Will be used for both slow/fast */
+ };
+ };
+};