boards: nxp: frdm_mcxw71: Enable MCXW71 I2C Loopback

Enable and test I2C loopback with i2c_target_api

Signed-off-by: Emilio Benavente <[email protected]>

boards/nxp/frdm_mcxw71/frdm_mcxw71-pinctrl.dtsi

@@ -32,6 +32,16 @@
 		};
 	};
 
+	pinmux_lpi2c0: pinmux_lpi2c0 {
+		group0 {
+			pinmux = <LPI2C0_SCL_PTA19>,
+				<LPI2C0_SDA_PTA18>;
+			drive-strength = "low";
+			slew-rate = "fast";
+			drive-open-drain;
+		};
+	};
+
 	pinmux_lpi2c1: pinmux_lpi2c1 {
 		group0 {
 			pinmux = <LPI2C1_SCL_PTB5>,

soc/nxp/mcx/mcxw/soc.c

@@ -136,6 +136,10 @@ static ALWAYS_INLINE void clock_init(void)
 		CLOCK_EnableClock(kCLOCK_PortA);
 	}
 
+	if (DT_NODE_HAS_COMPAT_STATUS(DT_NODELABEL(gpiob), nxp_kinetis_gpio, okay)) {
+		CLOCK_EnableClock(kCLOCK_PortB);
+	}
+
 	if (DT_NODE_HAS_COMPAT_STATUS(DT_NODELABEL(gpioc), nxp_kinetis_gpio, okay)) {
 		CLOCK_EnableClock(kCLOCK_PortC);
 	}

tests/drivers/i2c/i2c_target_api/boards/frdm_mcxw71.conf

@@ -0,0 +1 @@
+CONFIG_I2C_VIRTUAL=n

tests/drivers/i2c/i2c_target_api/boards/frdm_mcxw71.overlay

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * This is a looback setup for the frdm_mcxw71
+ * To test this sample, connect J2.1 <-> J1.5 and J2.2 <-> J2.9
+ */
+&lpi2c1 {
+	status = "okay";
+	eeprom0: eeprom@54 {
+		compatible = "zephyr,i2c-target-eeprom";
+		reg = <0x54>;
+		size = <256>;
+	};
+};
+
+&lpi2c0 {
+	status = "okay";
+	pinctrl-0 = <&pinmux_lpi2c0>;
+	pinctrl-names = "default";
+	eeprom1: eeprom@56 {
+		compatible = "zephyr,i2c-target-eeprom";
+		reg = <0x56>;
+		size = <256>;
+	};
+};
+
+&gpiob {
+	status = "okay";
+};
+
+&gpioa {
+	status = "okay";
+};