[PATCH 0/3] Add support for ADC on stm32mp157a-dk1

[PATCH 0/3] Add support for ADC on stm32mp157a-dk1

[Fabrice Gasnier]

This series adds support for ADC on stm32mp157a-dk1 board:
- enable vrefbuf regulator used as reference voltage
- define ADC pins for AIN connector and USB Type-C CC pins
- configure ADC1 and ADC2 to use these

Fabrice Gasnier (3):
  ARM: dts: stm32: Enable VREFBUF on stm32mp157a-dk1
  ARM: dts: stm32: add ADC pins used on stm32mp157a-dk1
  ARM: dts: stm32: enable ADC support on stm32mp157a-dk1

 arch/arm/boot/dts/stm32mp157-pinctrl.dtsi | 16 +++++++++++++++
 arch/arm/boot/dts/stm32mp157a-dk1.dts     | 34 +++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

-- 
2.7.4

[PATCH 1/3] ARM: dts: stm32: Enable VREFBUF on stm32mp157a-dk1

[Fabrice Gasnier]

Enable VREFBUF as ADC/DAC uses it on stm32mp157a-dk1 board.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 arch/arm/boot/dts/stm32mp157a-dk1.dts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp157a-dk1.dts b/arch/arm/boot/dts/stm32mp157a-dk1.dts
index 0615d1c..ebd9f33 100644
--- a/arch/arm/boot/dts/stm32mp157a-dk1.dts
+++ b/arch/arm/boot/dts/stm32mp157a-dk1.dts
@@ -449,3 +449,10 @@
 	pinctrl-0 = <&uart4_pins_a>;
 	status = "okay";
 };
+
+&vrefbuf {
+	regulator-min-microvolt = <2500000>;
+	regulator-max-microvolt = <2500000>;
+	vdda-supply = <&vdd>;
+	status = "okay";
+};
-- 
2.7.4

[PATCH 2/3] ARM: dts: stm32: add ADC pins used on stm32mp157a-dk1

[Fabrice Gasnier]

Define pins that can be used for ADC on stm32mp157a-dk1 board:
- AIN connector has ADC input pins
- USB Type-C CC1 & CC2 pins (e.g. in18, in19)

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 arch/arm/boot/dts/stm32mp157-pinctrl.dtsi | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp157-pinctrl.dtsi b/arch/arm/boot/dts/stm32mp157-pinctrl.dtsi
index e4a0d51..eeb60d0 100644
--- a/arch/arm/boot/dts/stm32mp157-pinctrl.dtsi
+++ b/arch/arm/boot/dts/stm32mp157-pinctrl.dtsi
@@ -137,6 +137,22 @@
 				status = "disabled";
 			};
 
+			adc12_ain_pins_a: adc12-ain-0 {
+				pins {
+					pinmux = <STM32_PINMUX('C', 3, ANALOG)>, /* ADC1 in13 */
+						 <STM32_PINMUX('F', 12, ANALOG)>, /* ADC1 in6 */
+						 <STM32_PINMUX('F', 13, ANALOG)>, /* ADC2 in2 */
+						 <STM32_PINMUX('F', 14, ANALOG)>; /* ADC2 in6 */
+				};
+			};
+
+			adc12_usb_cc_pins_a: adc12-usb-cc-pins-0 {
+				pins {
+					pinmux = <STM32_PINMUX('A', 4, ANALOG)>, /* ADC12 in18 */
+						 <STM32_PINMUX('A', 5, ANALOG)>; /* ADC12 in19 */
+				};
+			};
+
 			cec_pins_a: cec-0 {
 				pins {
 					pinmux = <STM32_PINMUX('A', 15, AF4)>;
-- 
2.7.4

[PATCH 3/3] ARM: dts: stm32: enable ADC support on stm32mp157a-dk1

[Fabrice Gasnier]

Configure ADC support on stm32mp157a-dk1. It can be used for various
purpose:
- AIN connector has several analog inputs: ANA0, ANA1, ADC2 in6 & in2,
  ADC1 in13 & in6
- USB Type-C CC1 & CC2 pins wired to in18 & in19
It's easier then to Configure them all. But keep them disabled by default,
so the pins are kept in their initial state to lower power consumption.
This way they can also be used as GPIO.
Add VDD and VDDA supplies to ADC on stm32mp157c-dk1 board. This allows to
get full ADC analog performances in case VDDA is below 2.7V (not the case
by default).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 arch/arm/boot/dts/stm32mp157a-dk1.dts | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp157a-dk1.dts b/arch/arm/boot/dts/stm32mp157a-dk1.dts
index ebd9f33..2f42fcd 100644
--- a/arch/arm/boot/dts/stm32mp157a-dk1.dts
+++ b/arch/arm/boot/dts/stm32mp157a-dk1.dts
@@ -97,6 +97,33 @@
 	};
 };
 
+&adc {
+	pinctrl-names = "default";
+	pinctrl-0 = <&adc12_ain_pins_a>, <&adc12_usb_cc_pins_a>;
+	vdd-supply = <&vdd>;
+	vdda-supply = <&vdd>;
+	vref-supply = <&vrefbuf>;
+	status = "disabled";
+	adc1: adc@0 {
+		/*
+		 * Type-C USB_PWR_CC1 & USB_PWR_CC2 on in18 & in19.
+		 * Use at least 5 * RC time, e.g. 5 * (Rp + Rd) * C:
+		 * 5 * (56 + 47kOhms) * 5pF => 2.5us.
+		 * Use arbitrary margin here (e.g. 5us).
+		 */
+		st,min-sample-time-nsecs = <5000>;
+		/* AIN connector, USB Type-C CC1 & CC2 */
+		st,adc-channels = <0 1 6 13 18 19>;
+		status = "okay";
+	};
+	adc2: adc@100 {
+		/* AIN connector, USB Type-C CC1 & CC2 */
+		st,adc-channels = <0 1 2 6 18 19>;
+		st,min-sample-time-nsecs = <5000>;
+		status = "okay";
+	};
+};
+
 &cec {
 	pinctrl-names = "default", "sleep";
 	pinctrl-0 = <&cec_pins_b>;
-- 
2.7.4

Re: [PATCH 0/3] Add support for ADC on stm32mp157a-dk1

[Alexandre Torgue]

Hi Fabrice

On 9/13/19 4:34 PM, Fabrice Gasnier wrote:
> This series adds support for ADC on stm32mp157a-dk1 board:
> - enable vrefbuf regulator used as reference voltage
> - define ADC pins for AIN connector and USB Type-C CC pins
> - configure ADC1 and ADC2 to use these
> 
> Fabrice Gasnier (3):
>    ARM: dts: stm32: Enable VREFBUF on stm32mp157a-dk1
>    ARM: dts: stm32: add ADC pins used on stm32mp157a-dk1
>    ARM: dts: stm32: enable ADC support on stm32mp157a-dk1
> 
>   arch/arm/boot/dts/stm32mp157-pinctrl.dtsi | 16 +++++++++++++++
>   arch/arm/boot/dts/stm32mp157a-dk1.dts     | 34 +++++++++++++++++++++++++++++++
>   2 files changed, 50 insertions(+)
> 

Series applied on stm32-next.

Regards
Alex