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 915ba2526f4515e73f4bc4973a217309c6e635ec..1ce01bac98142ca26ead3bb6eb4a8c9991ab6483 100644 (file)
--- 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 {