linux-kernel - [RFC/RFT 14/14] arm64: dts: meson-g12b-odroid-n2: enable DVFS

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Message-Id: <20190620150013.13462-15-narmstrong@baylibre.com>
Date:   Thu, 20 Jun 2019 17:00:13 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     jbrunet@...libre.com, khilman@...libre.com
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, martin.blumenstingl@...glemail.com,
        Neil Armstrong <narmstrong@...libre.com>
Subject: [RFC/RFT 14/14] arm64: dts: meson-g12b-odroid-n2: enable DVFS

Enable DVFS for the Odroid-N2 by setting the clock, OPP and supply
for each cores of each CPU clusters.

The first cluster uses the "VDDCPU_B" power supply, and the second
cluster uses the "VDDCPU_A" power supply.

Each power supply can achieve 0.73V to 1.01V using 2 distinct PWM
outputs clocked at 800KHz with an inverse duty-cycle.

DVFS has been tested by running the arm64 cpuburn at [1] and cycling
between all the possible cpufreq translations of each cluster and
checking the final frequency using the clock-measurer, script at [2].

[1] https://github.com/ssvb/cpuburn-arm/blob/master/cpuburn-a53.S
[2] https://gist.github.com/superna9999/d4de964dbc0f84b7d527e1df2ddea25f

Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 .../boot/dts/amlogic/meson-g12b-odroid-n2.dts | 96 +++++++++++++++++++
 1 file changed, 96 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
index c3e0735e6d9f..0db1547bfb5a 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
@@ -114,6 +114,44 @@
 		/* FIXME: actually controlled by VDDCPU_B_EN */
 	};
 
+	vddcpu_a: regulator-vddcpu-a {
+		/*
+		 * MP8756GD Regulator.
+		 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VDDCPU_A";
+		regulator-min-microvolt = <721000>;
+		regulator-max-microvolt = <1022000>;
+
+		vin-supply = <&main_12v>;
+
+		pwms = <&pwm_ab 0 1250 0>;
+		pwm-dutycycle-range = <100 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
+	vddcpu_b: regulator-vddcpu-b {
+		/*
+		 * Silergy SY8120B1ABC Regulator.
+		 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VDDCPU_B";
+		regulator-min-microvolt = <721000>;
+		regulator-max-microvolt = <1022000>;
+
+		vin-supply = <&main_12v>;
+
+		pwms = <&pwm_AO_cd 1 1250 0>;
+		pwm-dutycycle-range = <100 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	hub_5v: regulator-hub_5v {
 		compatible = "regulator-fixed";
 		regulator-name = "HUB_5V";
@@ -245,6 +283,48 @@
 	status = "okay";
 };
 
+&cpu0 {
+	cpu-supply = <&vddcpu_b>;
+	operating-points-v2 = <&cpu_opp_table_0>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu1 {
+	cpu-supply = <&vddcpu_b>;
+	operating-points-v2 = <&cpu_opp_table_0>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu100 {
+	cpu-supply = <&vddcpu_a>;
+	operating-points-v2 = <&cpub_opp_table_1>;
+	clocks = <&clkc CLKID_CPUB_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu101 {
+	cpu-supply = <&vddcpu_a>;
+	operating-points-v2 = <&cpub_opp_table_1>;
+	clocks = <&clkc CLKID_CPUB_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu102 {
+	cpu-supply = <&vddcpu_a>;
+	operating-points-v2 = <&cpub_opp_table_1>;
+	clocks = <&clkc CLKID_CPUB_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu103 {
+	cpu-supply = <&vddcpu_a>;
+	operating-points-v2 = <&cpub_opp_table_1>;
+	clocks = <&clkc CLKID_CPUB_CLK>;
+	clock-latency = <50000>;
+};
+
 &ext_mdio {
 	external_phy: ethernet-phy@0 {
 		/* Realtek RTL8211F (0x001cc916) */	
@@ -308,6 +388,22 @@
 	pinctrl-names = "default";
 };
 
+&pwm_ab {
+	pinctrl-0 = <&pwm_a_e_pins>;
+	pinctrl-names = "default";
+	clocks = <&xtal>;
+	clock-names = "clkin0";
+	status = "okay";
+};
+
+&pwm_AO_cd {
+	pinctrl-0 = <&pwm_ao_d_e_pins>;
+	pinctrl-names = "default";
+	clocks = <&xtal>;
+	clock-names = "clkin1";
+	status = "okay";
+};
+
 /* SD card */
 &sd_emmc_b {
 	status = "okay";
-- 
2.21.0