[PATCH v1 1/7] ARM: dts: stm32: stm32mp15x-mecio1-io: Enable internal ADC reference

[Oleksij Rempel <o.rempel@pengutronix.de>]

From: David Jander <david@protonic.nl>

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")
Cc: <stable@vger.kernel.org>
Signed-off-by: David Jander <david@protonic.nl>
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi b/arch/arm/boot/dts/st/stm32mp15x-mecio1-io.dtsi
index 915ba2526f45..1ce01bac9814 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 @@ &adc {
 	pinctrl-names = "default";
 	vdd-supply = <&v3v3>;
 	vdda-supply = <&v3v3>;
-	vref-supply = <&v3v3>;
+	vref-supply = <&vrefbuf>;
 	status = "okay";
 };
 
@@ -412,6 +412,13 @@ &usbphyc_port1 {
 	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 {
-- 
2.47.3