arm64: dts: qcom: msm8996: Add PSCI cpuidle low power states

Add device bindings for cpuidle states for cpu devices.

msm8996 features 4 cpus - 2 in each cluster. However, all cpus implement
the same microarchitecture and the two clusters only differ in the
maximum frequency attainable by the CPUs.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <agross@kernel.org>

arch/arm64/boot/dts/qcom/msm8996.dtsi

@@ -102,6 +102,7 @@ CPU0: cpu@0 {
 			compatible = "qcom,kryo";
 			reg = <0x0 0x0>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			next-level-cache = <&L2_0>;
 			L2_0: l2-cache {
 			      compatible = "cache";
@@ -114,6 +115,7 @@ CPU1: cpu@1 {
 			compatible = "qcom,kryo";
 			reg = <0x0 0x1>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			next-level-cache = <&L2_0>;
 		};
 
@@ -122,6 +124,7 @@ CPU2: cpu@100 {
 			compatible = "qcom,kryo";
 			reg = <0x0 0x100>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			next-level-cache = <&L2_1>;
 			L2_1: l2-cache {
 			      compatible = "cache";
@@ -134,6 +137,7 @@ CPU3: cpu@101 {
 			compatible = "qcom,kryo";
 			reg = <0x0 0x101>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			next-level-cache = <&L2_1>;
 		};
 
@@ -158,6 +162,19 @@ core1 {
 				};
 			};
 		};
+
+		idle-states {
+			entry-method = "psci";
+
+			CPU_SLEEP_0: cpu-sleep-0 {
+				compatible = "arm,idle-state";
+				idle-state-name = "standalone-power-collapse";
+				arm,psci-suspend-param = <0x00000004>;
+				entry-latency-us = <40>;
+				exit-latency-us = <80>;
+				min-residency-us = <300>;
+			};
+		};
 	};
 
 	thermal-zones {