ARM: dts: stm32mp1: Add adc nodes

Add adc related nodes. These nodes are used to detect the
current supplied by USB type-C power in port on DK1 and DK2
boards.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/dts/stm32mp157-pinctrl.dtsi b/arch/arm/dts/stm32mp157-pinctrl.dtsi
index 4d2bf33..c069875 100644
--- a/arch/arm/dts/stm32mp157-pinctrl.dtsi
+++ b/arch/arm/dts/stm32mp157-pinctrl.dtsi
@@ -148,6 +148,13 @@
 				gpio-ranges = <&pinctrl 0 160 8>;
 			};
 
+			adc12_usb_pwr_pins_a: adc12-usb-pwr-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)>;
diff --git a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
index b4cfba0..af7acfa 100644
--- a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
+++ b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
@@ -31,6 +31,27 @@
 	};
 };
 
+&adc {
+	pinctrl-names = "default";
+	pinctrl-0 = <&adc12_usb_pwr_pins_a>;
+	vdd-supply = <&vdd>;
+	vdda-supply = <&vdd>;
+	vref-supply = <&vrefbuf>;
+	status = "okay";
+	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. 5µs).
+		 */
+		st,min-sample-time-nsecs = <5000>;
+		/* ANA0, ANA1, USB Type-C CC1 & CC2 */
+		st,adc-channels = <0 1 18 19>;
+		status = "okay";
+	};
+};
+
 &clk_hse {
 	st,digbypass;
 };