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From:   Neil Armstrong <narmstrong@baylibre.com>
To:     jbrunet@baylibre.com, khilman@baylibre.com
Cc:     linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, martin.blumenstingl@googlemail.com,
        Neil Armstrong <narmstrong@baylibre.com>
Subject: [RFC/RFT 12/14] arm64: dts: meson-g12a: enable DVFS on G12A boards
Date:   Thu, 20 Jun 2019 17:00:11 +0200
Message-Id: <20190620150013.13462-13-narmstrong@baylibre.com>
In-Reply-To: <20190620150013.13462-1-narmstrong@baylibre.com>
References: <20190620150013.13462-1-narmstrong@baylibre.com>
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Enable DVFS for the U200, SEI520 and X96-Max Amlogic G12A based board
by setting the clock, OPP and supply for each CPU cores.

The CPU cluster power supply can achieve 0.73V to 1.01V using a PWM
output 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 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@baylibre.com>
---
 .../boot/dts/amlogic/meson-g12a-sei510.dts    | 55 +++++++++++++++++++
 .../boot/dts/amlogic/meson-g12a-u200.dts      | 55 +++++++++++++++++++
 .../boot/dts/amlogic/meson-g12a-x96-max.dts   | 52 ++++++++++++++++++
 3 files changed, 162 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts b/arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts
index bd26b35102ff..be45437c51e1 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts
@@ -129,6 +129,25 @@
 		enable-active-high;
 	};
 
+	vddcpu: regulator-vddcpu {
+		/*
+		 * SY8120B1ABC DC/DC Regulator.
+		 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VDDCPU";
+		regulator-min-microvolt = <721000>;
+		regulator-max-microvolt = <1022000>;
+
+		vin-supply = <&dc_in>;
+
+		pwms = <&pwm_AO_cd 1 1250 0>;
+		pwm-dutycycle-range = <100 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	vddio_ao1v8: regulator-vddio_ao1v8 {
 		compatible = "regulator-fixed";
 		regulator-name = "VDDIO_AO1V8";
@@ -297,6 +316,34 @@
 	status = "okay";
 };
 
+&cpu0 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu1 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu2 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu3 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
 &cvbs_vdac_port {
 	cvbs_vdac_out: endpoint {
 		remote-endpoint = <&cvbs_connector_in>;
@@ -339,6 +386,14 @@
 	pinctrl-names = "default";
 };
 
+&pwm_AO_cd {
+	pinctrl-0 = <&pwm_ao_d_e_pins>;
+	pinctrl-names = "default";
+	clocks = <&xtal>;
+	clock-names = "clkin1";
+	status = "okay";
+};
+
 &pwm_ef {
 	status = "okay";
 	pinctrl-0 = <&pwm_e_pins>;
diff --git a/arch/arm64/boot/dts/amlogic/meson-g12a-u200.dts b/arch/arm64/boot/dts/amlogic/meson-g12a-u200.dts
index 332a4b27174b..b6bd96ee394a 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12a-u200.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12a-u200.dts
@@ -136,6 +136,25 @@
 		regulator-always-on;
 	};
 
+	vddcpu: regulator-vddcpu {
+		/*
+		 * MP8756GD Regulator.
+		 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VDDCPU";
+		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;
+	};
+
 	sound {
 		compatible = "amlogic,axg-sound-card";
 		model = "G12A-U200";
@@ -305,6 +324,34 @@
 	status = "okay";
 };
 
+&cpu0 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu1 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu2 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu3 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
 &cvbs_vdac_port {
 	cvbs_vdac_out: endpoint {
 		remote-endpoint = <&cvbs_connector_in>;
@@ -369,6 +416,14 @@
 	pinctrl-names = "default";
 };
 
+&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";
diff --git a/arch/arm64/boot/dts/amlogic/meson-g12a-x96-max.dts b/arch/arm64/boot/dts/amlogic/meson-g12a-x96-max.dts
index d37868d21114..099ccf67547e 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12a-x96-max.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12a-x96-max.dts
@@ -132,6 +132,22 @@
 		regulator-always-on;
 	};
 
+	vddcpu: regulator-vddcpu {
+		compatible = "pwm-regulator";
+
+		regulator-name = "VDDCPU";
+		regulator-min-microvolt = <721000>;
+		regulator-max-microvolt = <1022000>;
+
+		vin-supply = <&dc_in>;
+
+		pwms = <&pwm_AO_cd 1 1250 0>;
+		pwm-dutycycle-range = <100 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	sound {
 		compatible = "amlogic,axg-sound-card";
 		model = "G12A-X96-MAX";
@@ -242,6 +258,34 @@
 	status = "okay";
 };
 
+&cpu0 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu1 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu2 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
+&cpu3 {
+	cpu-supply = <&vddcpu>;
+	operating-points-v2 = <&cpu_opp_table>;
+	clocks = <&clkc CLKID_CPU_CLK>;
+	clock-latency = <50000>;
+};
+
 &cvbs_vdac_port {
 	cvbs_vdac_out: endpoint {
 		remote-endpoint = <&cvbs_connector_in>;
@@ -279,6 +323,14 @@
 	pinctrl-names = "default";
 };
 
+&pwm_AO_cd {
+	pinctrl-0 = <&pwm_ao_d_e_pins>;
+	pinctrl-names = "default";
+	clocks = <&xtal>;
+	clock-names = "clkin1";
+	status = "okay";
+};
+
 &ext_mdio {
 	external_phy: ethernet-phy@0 {
 		/* Realtek RTL8211F (0x001cc916) */
-- 
2.21.0