ARM: dts: stm32: add STMFX support on stm32746g-eval

This patch adds support for STMicroelectronics Multi-Function eXpander
(STMFX) on stm32746g-eval. It is connected on i2c1.
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32746g-eval.dts

@@ -44,6 +44,7 @@
 #include "stm32f746.dtsi"
 #include "stm32f746-pinctrl.dtsi"
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/interrupt-controller/irq.h>
 
 / {
 	model = "STMicroelectronics STM32746g-EVAL board";
@@ -115,6 +116,22 @@ &i2c1 {
 	i2c-scl-rising-time-ns = <185>;
 	i2c-scl-falling-time-ns = <20>;
 	status = "okay";
+
+	stmfx: stmfx@42 {
+		compatible = "st,stmfx-0300";
+		reg = <0x42>;
+		interrupts = <8 IRQ_TYPE_EDGE_RISING>;
+		interrupt-parent = <&gpioi>;
+
+		stmfx_pinctrl: stmfx-pin-controller {
+			compatible = "st,stmfx-0300-pinctrl";
+			gpio-controller;
+			#gpio-cells = <2>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
+			gpio-ranges = <&stmfx_pinctrl 0 0 24>;
+		};
+	};
 };
 
 &rtc {