PM / AVS: exynos-avs: Add binding document for exynos-avs

This patch adds a device tree binding document describing the exynos AVS
device driver.

Change-Id: I6f40e5ee9d9c796f3318dbfd71448c63f9467f8e
Signed-off-by: Wook Song <wook16.song@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/Documentation/devicetree/bindings/power/exynos-avs.txt b/Documentation/devicetree/bindings/power/exynos-avs.txt
new file mode 100644 (file)
index 0000000..bb1a10a
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/exynos-avs.txt
@@ -0,0 +1,81 @@
+* Samsung Exynos Adaptive Voltage Scaling
+
+Required properties:
+- compatible: should be "samsung,exynos5433-avs" for Exynos 5433.
+- resource: the phandle for the resource which requires the AVS feature.
+- operating-points: For details, refer to [1].
+- vdd-supply: the phandle to the regulator that provides power to the resource.
+- An empty property which is one of:
+  - "samsung,avs-type-cpu-little"
+  - "samsung,avs-type-cpu-big"
+  is required to describe the resource type which requires the AVS feature.
+
+[1] Documentation/devicetree/bindings/power/opp.txt
+
+Required properties for "samsung,exynos5433-avs"
+- samsung,chipid-syscon: the phandle of the syscon node for the chipid
+                       register set.
+
+Example 1) exynos-avs nodes in exynos5433.dtsi are as follows:
+
+               /* Soc Common File */
+
+               exynos_avs_cpu0: exynos-avs@0 {
+                       compatible = "samsung,exynos5433-avs";
+                       samsung,chipid-syscon = <&chipid>;
+                       resource = <&cpu0>;
+                       operating-points = <
+                               1300000 1125000
+                               1200000 1075000
+                               1100000 1037500
+                               1000000 1000000
+                               900000  950000
+                               800000  925000
+                               700000  887500
+                               600000  862500
+                               500000  837500
+                               400000  800000
+                       >;
+                       samsung,asv-type-cpu-little;
+                       status = "disabled";
+               };
+
+               exynos_avs_cpu4: exynos-avs@1 {
+                       compatible = "samsung,exynos5433-avs";
+                       samsung,chipid-syscon = <&chipid>;
+                       resource = <&cpu4>;
+                       operating-points = <
+                               1900000 1212500
+                               1800000 1175000
+                               1700000 1137500
+                               1600000 1087500
+                               1500000 1050000
+                               1400000 1025000
+                               1300000 1000000
+                               1200000 975000
+                               1100000 950000
+                               1000000 925000
+                               900000  900000
+                               800000  900000
+                               700000  900000
+                               600000  900000
+                               500000  900000
+                       >;
+                       samsung,avs-type-cpu-big;
+                       status = "disabled";
+                };
+
+Example 2) The vdd-supply property of each exynos-avs node in exynos5433-tm2.dts
+           is listed below.
+
+               /*  Board Specific .dts File */
+
+               &exynos_avs_cpu0 {
+                       vdd-supply = <&buck3_reg>;
+                       status = "okay";
+               };
+
+               &exynos_avs_cpu4 {
+                       vdd-supply = <&buck2_reg>;
+                       status = "okay";
+               };