From: David Jander <david@protonic.nl>
Date: Wed, 18 Mar 2026 10:51:17 +0000 (+0100)
Subject: ARM: dts: stm32: stm32mp15x-mecio1-io: Enable internal ADC reference
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c84f22405085d91cd5f0c5b967318371c07904ba;p=thirdparty%2Fkernel%2Flinux.git

ARM: dts: stm32: stm32mp15x-mecio1-io: Enable internal ADC reference

Switch the ADC reference supply from the general 3.3V rail to the
internal 2.5V VREFBUF regulator. The ADC circuits on this board are
designed for the internal 2.5V reference. Without this change, all ADC
measurement values are incorrect.

Fixes: 8267753c891c ("ARM: dts: stm32: Add MECIO1 and MECT1S board variants")
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20260318105123.819807-2-o.rempel@pengutronix.de
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
---

diff --git a/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi b/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi
index 915ba2526f451..1ce01bac98142 100644
--- a/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi
+++ b/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi
@@ -95,7 +95,7 @@
 	pinctrl-names = "default";
 	vdd-supply = <&v3v3>;
 	vdda-supply = <&v3v3>;
-	vref-supply = <&v3v3>;
+	vref-supply = <&vrefbuf>;
 	status = "okay";
 };
 
@@ -412,6 +412,13 @@
 	phy-supply = <&v3v3>;
 };
 
+&vrefbuf {
+	regulator-min-microvolt = <2500000>;
+	regulator-max-microvolt = <2500000>;
+	vdda-supply = <&v3v3>;
+	status = "okay";
+};
+
 &pinctrl {
 	adc12_pins_mecsbc: adc12-ain-mecsbc-0 {
 		pins {