arm64: dts: allwinner: h5: Add CPU Operating Performance Points table

Add an OPP (Operating Performance Points) table for the CPU cores for
boards to include to DVFS (Dynamic Voltage & Frequency Scaling) on the
H5. The table originates from Armbian, but the maximum voltage is raised
slightly to account for boards using slightly higher voltages.

The table and tie in to the CPU cores are put in a separate dtsi file
that board files can include to opt in. Or they can define their own
tables if the standard one does not fit.

This has been tested on the Libre Computer ALL-H3-CC-H5 and the Bananapi
M2+ v1.2 H5, both with adequate cooling. The former has a fixed 1.2V
regulator, while the latter has a GPIO controlled regulator switchable
between 1.1V and 1.3V.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20200717160053.31191-7-wens@kernel.org

arch/arm64/boot/dts/allwinner/sun50i-h5-cpu-opp.dtsi

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+// Copyright (C) 2020 Chen-Yu Tsai <wens@csie.org>
+
+/ {
+	cpu_opp_table: cpu-opp-table {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp-408000000 {
+			opp-hz = /bits/ 64 <408000000>;
+			opp-microvolt = <1000000 1000000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-648000000 {
+			opp-hz = /bits/ 64 <648000000>;
+			opp-microvolt = <1040000 1040000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-816000000 {
+			opp-hz = /bits/ 64 <816000000>;
+			opp-microvolt = <1080000 1080000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-912000000 {
+			opp-hz = /bits/ 64 <912000000>;
+			opp-microvolt = <1120000 1120000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-960000000 {
+			opp-hz = /bits/ 64 <960000000>;
+			opp-microvolt = <1160000 1160000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-1008000000 {
+			opp-hz = /bits/ 64 <1008000000>;
+			opp-microvolt = <1200000 1200000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-1056000000 {
+			opp-hz = /bits/ 64 <1056000000>;
+			opp-microvolt = <1240000 1240000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-1104000000 {
+			opp-hz = /bits/ 64 <1104000000>;
+			opp-microvolt = <1260000 1260000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+
+		opp-1152000000 {
+			opp-hz = /bits/ 64 <1152000000>;
+			opp-microvolt = <1300000 1300000 1310000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+	};
+};
+
+&cpu0 {
+	operating-points-v2 = <&cpu_opp_table>;
+};
+
+&cpu1 {
+	operating-points-v2 = <&cpu_opp_table>;
+};
+
+&cpu2 {
+	operating-points-v2 = <&cpu_opp_table>;
+};
+
+&cpu3 {
+	operating-points-v2 = <&cpu_opp_table>;
+};