[PATCH 0/4] Meson8b: Odroid-C1 improvements

[PATCH 0/4] Meson8b: Odroid-C1 improvements

[Martin Blumenstingl]

This is a small collection of improvements for the Odroid-C1 board.
My main goal is to prepare the CPU voltage regulator as I'm using
the Odroid-C1 to test my changes which will enable CPU frequency
scaling on Meson8/Meson8b/Meson8m2.

While I was going through the schematics anyways I added more
regulators, enabled the SAR ADC and added the /chosen/stdout-path
property to make debugging with "earlycon" easier.

schematics for the board are published by Hardkernel and can be found
here: [0]

NOTE: This series depends on my patch "ARM: dts: meson8b: add the
I2C_A, PWM_C and UART_B pins" [1] from my other series called
"Meson8b: add support for the Endless Mini EC-100" as this defines
the "pwm_c1_pins" for the CPU voltage regulator (which is controlled
via PWM).


[0] https://dn.odroid.com/S805/Schematics/odroid-c1+_rev0.4_20150615.pdf
[1] https://patchwork.kernel.org/patch/10600043/
[2] https://patchwork.kernel.org/cover/10600031/

Martin Blumenstingl (4):
  ARM: dts: meson8b: odroidc1: add the CPU voltage regulator
  ARM: dts: meson8b: odroidc1: add the fixed voltage regulators
  ARM: dts: meson8b: odroidc1: enable the SAR ADC
  ARM: dts: meson8b: odroidc1: add stdout-path property

 arch/arm/boot/dts/meson8b-odroidc1.dts | 109 +++++++++++++++++++++++++
 1 file changed, 109 insertions(+)

-- 
2.19.0

[PATCH 0/4] Meson8b: Odroid-C1 improvements

[Martin Blumenstingl]

This is a small collection of improvements for the Odroid-C1 board.
My main goal is to prepare the CPU voltage regulator as I'm using
the Odroid-C1 to test my changes which will enable CPU frequency
scaling on Meson8/Meson8b/Meson8m2.

While I was going through the schematics anyways I added more
regulators, enabled the SAR ADC and added the /chosen/stdout-path
property to make debugging with "earlycon" easier.

schematics for the board are published by Hardkernel and can be found
here: [0]

NOTE: This series depends on my patch "ARM: dts: meson8b: add the
I2C_A, PWM_C and UART_B pins" [1] from my other series called
"Meson8b: add support for the Endless Mini EC-100" as this defines
the "pwm_c1_pins" for the CPU voltage regulator (which is controlled
via PWM).


[0] https://dn.odroid.com/S805/Schematics/odroid-c1+_rev0.4_20150615.pdf
[1] https://patchwork.kernel.org/patch/10600043/
[2] https://patchwork.kernel.org/cover/10600031/

Martin Blumenstingl (4):
  ARM: dts: meson8b: odroidc1: add the CPU voltage regulator
  ARM: dts: meson8b: odroidc1: add the fixed voltage regulators
  ARM: dts: meson8b: odroidc1: enable the SAR ADC
  ARM: dts: meson8b: odroidc1: add stdout-path property

 arch/arm/boot/dts/meson8b-odroidc1.dts | 109 +++++++++++++++++++++++++
 1 file changed, 109 insertions(+)

-- 
2.19.0

[PATCH 1/4] ARM: dts: meson8b: odroidc1: add the CPU voltage regulator

[Martin Blumenstingl]

The CPU voltage regulator is a "Monolithic Power Systems MP2161"
(according to the Odroid-C1+'s schematics). It is driven by PWM_C on
GPIODV_9.

Hardkernel's 3.10 kernel (based on the Amlogic GPL kernel sources)
defines a PWM voltage table with the following values:
- 0.86 volts = PWM register value 0x10f001b
- (more values in 0.1 volt increments)
- 1.14 volts = PWM register value 0x000012a
When using the XTAL (24MHz) as input this translates into a PWM period
of 12218ns with 0.86V using a duty cycle of 91% and 1.14V using a duty
cycle of 0%.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 27 ++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index ef3177d3da3d..0557823cdd64 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -101,6 +101,25 @@
 		states = <3300000 0
 			  1800000 1>;
 	};
+
+	vcck: regulator-vcck {
+		/* Monolithic Power Systems MP2161 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VCCK";
+		regulator-min-microvolt = <860000>;
+		regulator-max-microvolt = <1140000>;
+
+		pwms = <&pwm_cd 0 12218 0>;
+		pwm-dutycycle-range = <91 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+};
+
+&cpu0 {
+	cpu-supply = <&vcck>;
 };
 
 &ethmac {
@@ -180,6 +199,14 @@
 	};
 };
 
+&pwm_cd {
+	status = "okay";
+	pinctrl-0 = <&pwm_c1_pins>;
+	pinctrl-names = "default";
+	clocks = <&clkc CLKID_XTAL>;
+	clock-names = "clkin0";
+};
+
 &uart_AO {
 	status = "okay";
 	pinctrl-0 = <&uart_ao_a_pins>;
-- 
2.19.0

[PATCH 1/4] ARM: dts: meson8b: odroidc1: add the CPU voltage regulator

[Martin Blumenstingl]

The CPU voltage regulator is a "Monolithic Power Systems MP2161"
(according to the Odroid-C1+'s schematics). It is driven by PWM_C on
GPIODV_9.

Hardkernel's 3.10 kernel (based on the Amlogic GPL kernel sources)
defines a PWM voltage table with the following values:
- 0.86 volts = PWM register value 0x10f001b
- (more values in 0.1 volt increments)
- 1.14 volts = PWM register value 0x000012a
When using the XTAL (24MHz) as input this translates into a PWM period
of 12218ns with 0.86V using a duty cycle of 91% and 1.14V using a duty
cycle of 0%.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 27 ++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index ef3177d3da3d..0557823cdd64 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -101,6 +101,25 @@
 		states = <3300000 0
 			  1800000 1>;
 	};
+
+	vcck: regulator-vcck {
+		/* Monolithic Power Systems MP2161 */
+		compatible = "pwm-regulator";
+
+		regulator-name = "VCCK";
+		regulator-min-microvolt = <860000>;
+		regulator-max-microvolt = <1140000>;
+
+		pwms = <&pwm_cd 0 12218 0>;
+		pwm-dutycycle-range = <91 0>;
+
+		regulator-boot-on;
+		regulator-always-on;
+	};
+};
+
+&cpu0 {
+	cpu-supply = <&vcck>;
 };
 
 &ethmac {
@@ -180,6 +199,14 @@
 	};
 };
 
+&pwm_cd {
+	status = "okay";
+	pinctrl-0 = <&pwm_c1_pins>;
+	pinctrl-names = "default";
+	clocks = <&clkc CLKID_XTAL>;
+	clock-names = "clkin0";
+};
+
 &uart_AO {
 	status = "okay";
 	pinctrl-0 = <&uart_ao_a_pins>;
-- 
2.19.0

[PATCH 2/4] ARM: dts: meson8b: odroidc1: add the fixed voltage regulators

[Martin Blumenstingl]

There are multiple fixed regulators on the Odroid-C1 board. Add them so
they can be used when we add the devices that need them (SAR ADC needs
the 1.8V IOREF, RTC needs VDD_RTC).
These are:
- P5V0 is the main 5V power input
- VCC3V3 / VDDIO_AO3V3 / VDD3V3: fixed regulator with 3.3V output which
  is supplied by P5V0
- IOREF_1V8 / VCC1V8 / VDD1V8: fixed regulator with 1.8V output which is
  supplied by P5V0
- VDD_RTC: fixed voltage regulator with 0.9V output which is supplied by
  VDDIO_AO3V3
- DDR_VDDC / DDR3_1V5: fixed voltage regulator with 1.5V output which is
  supplied by P5V0
- the existing TF_IO and RFLASH_VDD_EN regulators are supplied by
  VDDIO_AO3V3
- the existing VCCK regulator is supplied by P5V0

This does not add the missing VDDEE regulator (controlled by PWM_D)
because it's not clear yet how to configure the voltage of that
regulator.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 73 ++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index 0557823cdd64..a08dccccdb5e 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -71,6 +71,14 @@
 		};
 	};
 
+	p5v0: regulator-p5v0 {
+		compatible = "regulator-fixed";
+
+		regulator-name = "P5V0";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+	};
+
 	tflash_vdd: regulator-tflash_vdd {
 		/*
 		 * signal name from schematics: TFLASH_VDD_EN
@@ -81,6 +89,8 @@
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
 
+		vin-supply = <&vcc_3v3>;
+
 		gpio = <&gpio GPIOY_12 GPIO_ACTIVE_HIGH>;
 		enable-active-high;
 	};
@@ -92,6 +102,8 @@
 		regulator-min-microvolt = <1800000>;
 		regulator-max-microvolt = <3300000>;
 
+		vin-supply = <&vcc_3v3>;
+
 		/*
 		 * signal name from schematics: TF_3V3N_1V8_EN
 		 */
@@ -102,6 +114,36 @@
 			  1800000 1>;
 	};
 
+	vcc_1v8: regulator-vcc-1v8 {
+		/*
+		 * RICHTEK RT9179 configured for a fixed output voltage of
+		 * 1.8V. This supplies not only VCC1V8 but also IOREF_1V8 and
+		 * VDD1V8 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VCC1V8";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+
+		vin-supply = <&p5v0>;
+	};
+
+	vcc_3v3: regulator-vcc-3v3 {
+		/*
+		 * Monolithic Power Systems MP2161 configured for a fixed
+		 * output voltage of 3.3V. This supplies not only VCC3V3 but
+		 * also VDD3V3 and VDDIO_AO3V3 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VCC3V3";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+
+		vin-supply = <&p5v0>;
+	};
+
 	vcck: regulator-vcck {
 		/* Monolithic Power Systems MP2161 */
 		compatible = "pwm-regulator";
@@ -110,12 +152,43 @@
 		regulator-min-microvolt = <860000>;
 		regulator-max-microvolt = <1140000>;
 
+		vin-supply = <&p5v0>;
+
 		pwms = <&pwm_cd 0 12218 0>;
 		pwm-dutycycle-range = <91 0>;
 
 		regulator-boot-on;
 		regulator-always-on;
 	};
+
+	vddc_ddr: regulator-vddc-ddr {
+		/*
+		 * Monolithic Power Systems MP2161 configured for a fixed
+		 * output voltage of 1.5V. This supplies not only DDR_VDDC but
+		 * also DDR3_1V5 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "DDR_VDDC";
+		regulator-min-microvolt = <1500000>;
+		regulator-max-microvolt = <1500000>;
+
+		vin-supply = <&p5v0>;
+	};
+
+	vdd_rtc: regulator-vdd-rtc {
+		/*
+		 * Torex Semiconductor XC6215 configured for a fixed output of
+		 * 0.9V.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VDD_RTC";
+		regulator-min-microvolt = <900000>;
+		regulator-max-microvolt = <900000>;
+
+		vin-supply = <&vcc_3v3>;
+	};
 };
 
 &cpu0 {
-- 
2.19.0

[PATCH 2/4] ARM: dts: meson8b: odroidc1: add the fixed voltage regulators

[Martin Blumenstingl]

There are multiple fixed regulators on the Odroid-C1 board. Add them so
they can be used when we add the devices that need them (SAR ADC needs
the 1.8V IOREF, RTC needs VDD_RTC).
These are:
- P5V0 is the main 5V power input
- VCC3V3 / VDDIO_AO3V3 / VDD3V3: fixed regulator with 3.3V output which
  is supplied by P5V0
- IOREF_1V8 / VCC1V8 / VDD1V8: fixed regulator with 1.8V output which is
  supplied by P5V0
- VDD_RTC: fixed voltage regulator with 0.9V output which is supplied by
  VDDIO_AO3V3
- DDR_VDDC / DDR3_1V5: fixed voltage regulator with 1.5V output which is
  supplied by P5V0
- the existing TF_IO and RFLASH_VDD_EN regulators are supplied by
  VDDIO_AO3V3
- the existing VCCK regulator is supplied by P5V0

This does not add the missing VDDEE regulator (controlled by PWM_D)
because it's not clear yet how to configure the voltage of that
regulator.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 73 ++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index 0557823cdd64..a08dccccdb5e 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -71,6 +71,14 @@
 		};
 	};
 
+	p5v0: regulator-p5v0 {
+		compatible = "regulator-fixed";
+
+		regulator-name = "P5V0";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+	};
+
 	tflash_vdd: regulator-tflash_vdd {
 		/*
 		 * signal name from schematics: TFLASH_VDD_EN
@@ -81,6 +89,8 @@
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
 
+		vin-supply = <&vcc_3v3>;
+
 		gpio = <&gpio GPIOY_12 GPIO_ACTIVE_HIGH>;
 		enable-active-high;
 	};
@@ -92,6 +102,8 @@
 		regulator-min-microvolt = <1800000>;
 		regulator-max-microvolt = <3300000>;
 
+		vin-supply = <&vcc_3v3>;
+
 		/*
 		 * signal name from schematics: TF_3V3N_1V8_EN
 		 */
@@ -102,6 +114,36 @@
 			  1800000 1>;
 	};
 
+	vcc_1v8: regulator-vcc-1v8 {
+		/*
+		 * RICHTEK RT9179 configured for a fixed output voltage of
+		 * 1.8V. This supplies not only VCC1V8 but also IOREF_1V8 and
+		 * VDD1V8 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VCC1V8";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+
+		vin-supply = <&p5v0>;
+	};
+
+	vcc_3v3: regulator-vcc-3v3 {
+		/*
+		 * Monolithic Power Systems MP2161 configured for a fixed
+		 * output voltage of 3.3V. This supplies not only VCC3V3 but
+		 * also VDD3V3 and VDDIO_AO3V3 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VCC3V3";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+
+		vin-supply = <&p5v0>;
+	};
+
 	vcck: regulator-vcck {
 		/* Monolithic Power Systems MP2161 */
 		compatible = "pwm-regulator";
@@ -110,12 +152,43 @@
 		regulator-min-microvolt = <860000>;
 		regulator-max-microvolt = <1140000>;
 
+		vin-supply = <&p5v0>;
+
 		pwms = <&pwm_cd 0 12218 0>;
 		pwm-dutycycle-range = <91 0>;
 
 		regulator-boot-on;
 		regulator-always-on;
 	};
+
+	vddc_ddr: regulator-vddc-ddr {
+		/*
+		 * Monolithic Power Systems MP2161 configured for a fixed
+		 * output voltage of 1.5V. This supplies not only DDR_VDDC but
+		 * also DDR3_1V5 according to the schematics.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "DDR_VDDC";
+		regulator-min-microvolt = <1500000>;
+		regulator-max-microvolt = <1500000>;
+
+		vin-supply = <&p5v0>;
+	};
+
+	vdd_rtc: regulator-vdd-rtc {
+		/*
+		 * Torex Semiconductor XC6215 configured for a fixed output of
+		 * 0.9V.
+		 */
+		compatible = "regulator-fixed";
+
+		regulator-name = "VDD_RTC";
+		regulator-min-microvolt = <900000>;
+		regulator-max-microvolt = <900000>;
+
+		vin-supply = <&vcc_3v3>;
+	};
 };
 
 &cpu0 {
-- 
2.19.0

[PATCH 3/4] ARM: dts: meson8b: odroidc1: enable the SAR ADC

[Martin Blumenstingl]

Odroid-C1 exposes ADC channels 0 and 1 on the GPIO headers. NOTE: Due
to the SoC design these are limited to 1.8V (instead of 3.3V like all
other pins).
Enable the SAR ADC to enable voltage measurements on these pins.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index a08dccccdb5e..7c1225658567 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -246,6 +246,11 @@
 	pinctrl-names = "default";
 };
 
+&saradc {
+	status = "okay";
+	vref-supply = <&vcc_1v8>;
+};
+
 &sdio {
 	status = "okay";
 
-- 
2.19.0

[PATCH 3/4] ARM: dts: meson8b: odroidc1: enable the SAR ADC

[Martin Blumenstingl]

Odroid-C1 exposes ADC channels 0 and 1 on the GPIO headers. NOTE: Due
to the SoC design these are limited to 1.8V (instead of 3.3V like all
other pins).
Enable the SAR ADC to enable voltage measurements on these pins.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index a08dccccdb5e..7c1225658567 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -246,6 +246,11 @@
 	pinctrl-names = "default";
 };
 
+&saradc {
+	status = "okay";
+	vref-supply = <&vcc_1v8>;
+};
+
 &sdio {
 	status = "okay";
 
-- 
2.19.0

[PATCH 4/4] ARM: dts: meson8b: odroidc1: add stdout-path property

[Martin Blumenstingl]

To use the "earlycon" kernel command line parameter (without arguments)
we need a stdout-path property under the /chosen node. Add this to make
it easier to spot errors early in the boot process when looking for
them.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index 7c1225658567..58669abda259 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -57,6 +57,10 @@
 		mmc0 = &sd_card_slot;
 	};
 
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
 	memory {
 		reg = <0x40000000 0x40000000>;
 	};
-- 
2.19.0

[PATCH 4/4] ARM: dts: meson8b: odroidc1: add stdout-path property

[Martin Blumenstingl]

To use the "earlycon" kernel command line parameter (without arguments)
we need a stdout-path property under the /chosen node. Add this to make
it easier to spot errors early in the boot process when looking for
them.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 arch/arm/boot/dts/meson8b-odroidc1.dts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index 7c1225658567..58669abda259 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -57,6 +57,10 @@
 		mmc0 = &sd_card_slot;
 	};
 
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
 	memory {
 		reg = <0x40000000 0x40000000>;
 	};
-- 
2.19.0

[PATCH 0/4] Meson8b: Odroid-C1 improvements

[Kevin Hilman]

Martin Blumenstingl <martin.blumenstingl@googlemail.com> writes:

> This is a small collection of improvements for the Odroid-C1 board.
> My main goal is to prepare the CPU voltage regulator as I'm using
> the Odroid-C1 to test my changes which will enable CPU frequency
> scaling on Meson8/Meson8b/Meson8m2.
>
> While I was going through the schematics anyways I added more
> regulators, enabled the SAR ADC and added the /chosen/stdout-path
> property to make debugging with "earlycon" easier.
>
> schematics for the board are published by Hardkernel and can be found
> here: [0]
>
> NOTE: This series depends on my patch "ARM: dts: meson8b: add the
> I2C_A, PWM_C and UART_B pins" [1] from my other series called
> "Meson8b: add support for the Endless Mini EC-100" as this defines
> the "pwm_c1_pins" for the CPU voltage regulator (which is controlled
> via PWM).

Applied to v4.20/dt (on top of the Endless series)

Thanks for pointing out the dependencies,

Kevin

[PATCH 0/4] Meson8b: Odroid-C1 improvements

[Kevin Hilman]

Martin Blumenstingl <martin.blumenstingl@googlemail.com> writes:

> This is a small collection of improvements for the Odroid-C1 board.
> My main goal is to prepare the CPU voltage regulator as I'm using
> the Odroid-C1 to test my changes which will enable CPU frequency
> scaling on Meson8/Meson8b/Meson8m2.
>
> While I was going through the schematics anyways I added more
> regulators, enabled the SAR ADC and added the /chosen/stdout-path
> property to make debugging with "earlycon" easier.
>
> schematics for the board are published by Hardkernel and can be found
> here: [0]
>
> NOTE: This series depends on my patch "ARM: dts: meson8b: add the
> I2C_A, PWM_C and UART_B pins" [1] from my other series called
> "Meson8b: add support for the Endless Mini EC-100" as this defines
> the "pwm_c1_pins" for the CPU voltage regulator (which is controlled
> via PWM).

Applied to v4.20/dt (on top of the Endless series)

Thanks for pointing out the dependencies,

Kevin