[PATCH v3 1/1] arm64: dts: rockchip: rk3528: Add CPU frequency scaling support

[Chukun Pan]

By default, the CPUs on RK3528 operates at 1.5GHz. Add CPU frequency and
voltage mapping to the device tree to enable dynamic scaling via cpufreq.

The OPP values come from downstream kernel[1], using a voltage close to
the actual frequency. Frequencies below 1.2GHz have been removed due to
the same voltage.

[1] https://github.com/rockchip-linux/kernel/blob/develop-5.10/arch/arm64/boot/dts/rockchip/rk3528.dtsi

Signed-off-by: Chukun Pan <amadeus at jmu.edu.cn>
---
 arch/arm64/boot/dts/rockchip/rk3528.dtsi | 39 ++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3528.dtsi b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
index 001a555c83b7..15fd9f99beaa 100644
--- a/arch/arm64/boot/dts/rockchip/rk3528.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
@@ -53,6 +53,7 @@ cpu0: cpu at 0 {
 			device_type = "cpu";
 			enable-method = "psci";
 			clocks = <&scmi_clk SCMI_CLK_CPU>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 
 		cpu1: cpu at 1 {
@@ -61,6 +62,7 @@ cpu1: cpu at 1 {
 			device_type = "cpu";
 			enable-method = "psci";
 			clocks = <&scmi_clk SCMI_CLK_CPU>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 
 		cpu2: cpu at 2 {
@@ -69,6 +71,7 @@ cpu2: cpu at 2 {
 			device_type = "cpu";
 			enable-method = "psci";
 			clocks = <&scmi_clk SCMI_CLK_CPU>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 
 		cpu3: cpu at 3 {
@@ -77,6 +80,7 @@ cpu3: cpu at 3 {
 			device_type = "cpu";
 			enable-method = "psci";
 			clocks = <&scmi_clk SCMI_CLK_CPU>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 	};
 
@@ -95,6 +99,41 @@ scmi_clk: protocol at 14 {
 		};
 	};
 
+	cpu_opp_table: opp-table-cpu {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp-1200000000 {
+			opp-hz = /bits/ 64 <1200000000>;
+			opp-microvolt = <875000 875000 1100000>;
+			clock-latency-ns = <40000>;
+		};
+
+		opp-1416000000 {
+			opp-hz = /bits/ 64 <1416000000>;
+			opp-microvolt = <925000 925000 1100000>;
+			clock-latency-ns = <40000>;
+		};
+
+		opp-1608000000 {
+			opp-hz = /bits/ 64 <1608000000>;
+			opp-microvolt = <975000 975000 1100000>;
+			clock-latency-ns = <40000>;
+		};
+
+		opp-1800000000 {
+			opp-hz = /bits/ 64 <1800000000>;
+			opp-microvolt = <1037500 1037500 1100000>;
+			clock-latency-ns = <40000>;
+		};
+
+		opp-2016000000 {
+			opp-hz = /bits/ 64 <2016000000>;
+			opp-microvolt = <1100000 1100000 1100000>;
+			clock-latency-ns = <40000>;
+		};
+	};
+
 	gpu_opp_table: opp-table-gpu {
 		compatible = "operating-points-v2";
 
-- 
2.25.1