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

[Oleksij Rempel]

From: David Jander <david at 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 at vger.kernel.org>
Signed-off-by: David Jander <david at protonic.nl>
Co-developed-by: Oleksij Rempel <o.rempel at pengutronix.de>
Signed-off-by: Oleksij Rempel <o.rempel at 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