ARM: tegra: ventana: Support CPU and Core voltage scaling

Support CPU and Core voltage scaling on Tegra20 Ventana board.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-ventana.dts

@@ -4,6 +4,7 @@
 #include <dt-bindings/input/input.h>
 #include "tegra20.dtsi"
 #include "tegra20-cpu-opp.dtsi"
+#include "tegra20-cpu-opp-microvolt.dtsi"
 
 / {
 	model = "NVIDIA Tegra20 Ventana evaluation board";
@@ -420,18 +421,28 @@ sys_reg: sys {
 					regulator-always-on;
 				};
 
-				sm0 {
+				vdd_core: sm0 {
 					regulator-name = "vdd_sm0,vdd_core";
-					regulator-min-microvolt = <1200000>;
-					regulator-max-microvolt = <1200000>;
+					regulator-min-microvolt = <950000>;
+					regulator-max-microvolt = <1300000>;
+					regulator-coupled-with = <&rtc_vdd &vdd_cpu>;
+					regulator-coupled-max-spread = <170000 550000>;
 					regulator-always-on;
+					regulator-boot-on;
+
+					nvidia,tegra-core-regulator;
 				};
 
-				sm1 {
+				vdd_cpu: sm1 {
 					regulator-name = "vdd_sm1,vdd_cpu";
-					regulator-min-microvolt = <1000000>;
-					regulator-max-microvolt = <1000000>;
+					regulator-min-microvolt = <750000>;
+					regulator-max-microvolt = <1125000>;
+					regulator-coupled-with = <&vdd_core &rtc_vdd>;
+					regulator-coupled-max-spread = <550000 550000>;
 					regulator-always-on;
+					regulator-boot-on;
+
+					nvidia,tegra-cpu-regulator;
 				};
 
 				sm2_reg: sm2 {
@@ -450,10 +461,16 @@ ldo1 {
 					regulator-always-on;
 				};
 
-				ldo2 {
+				rtc_vdd: ldo2 {
 					regulator-name = "vdd_ldo2,vdd_rtc";
-					regulator-min-microvolt = <1200000>;
-					regulator-max-microvolt = <1200000>;
+					regulator-min-microvolt = <950000>;
+					regulator-max-microvolt = <1300000>;
+					regulator-coupled-with = <&vdd_core &vdd_cpu>;
+					regulator-coupled-max-spread = <170000 550000>;
+					regulator-always-on;
+					regulator-boot-on;
+
+					nvidia,tegra-rtc-regulator;
 				};
 
 				ldo3 {
@@ -595,10 +612,12 @@ clk32k_in: clock@0 {
 
 	cpus {
 		cpu0: cpu@0 {
+			cpu-supply = <&vdd_cpu>;
 			operating-points-v2 = <&cpu0_opp_table>;
 		};
 
 		cpu@1 {
+			cpu-supply = <&vdd_cpu>;
 			operating-points-v2 = <&cpu0_opp_table>;
 		};
 	};