[PATCH 8/8] arm64: dts: st: add ADC support on stm32mp257f-ev1 board

[Fabrice Gasnier]

Add ADC support on stm32mp257f-ev1 board. ANA0 dedicated pin is wired on
mikroBUS connector, through a resistor divided and operational amplifier.
Configure adc1 channel0, and voltage divider in the DT. Keep it disabled
by default, to allow ADC to be used freely for other purpose.

--> | 470K | -+-- > | OpAmp (gain = 1) | --> ANA0 (to ADC1, ADC2 or ADC3)
              |
              v
           | 560K |
              |
              v
             ---
             GND

Signed-off-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
---
 arch/arm64/boot/dts/st/stm32mp257f-ev1.dts | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/boot/dts/st/stm32mp257f-ev1.dts b/arch/arm64/boot/dts/st/stm32mp257f-ev1.dts
index 14e033f365e3..f66eccee2139 100644
--- a/arch/arm64/boot/dts/st/stm32mp257f-ev1.dts
+++ b/arch/arm64/boot/dts/st/stm32mp257f-ev1.dts
@@ -160,6 +160,28 @@ mm_ospi1: mm-ospi at 60000000 {
 			no-map;
 		};
 	};
+
+	vdiv_ana0: voltage-divider-ana0 {
+		compatible = "voltage-divider";
+		io-channels = <&adc1 0>;
+		output-ohms = <560000>;
+		full-ohms = <1030000>;
+		status = "disabled";
+	};
+};
+
+&adc_12 {
+	/* Don't need a pinctrl for ANA0 dedicated pin e.g. Channel at 0 */
+	vdda-supply = <&scmi_vdda18adc>;
+	vref-supply = <&scmi_v1v8>;
+	status = "disabled";
+	adc1: adc at 0 {
+		status = "okay";
+		channel at 0 {
+			reg = <0>;
+			st,min-sample-time-ns = <400>;
+		};
+	};
 };
 
 &arm_wdt {

-- 
2.43.0