boards: frdm_mcxn236: add ewm support

1. Add EWM Support for frdm_mcxn236
2. verified tests/drivers/watchdog/wdt_basic_reset_none

Signed-off-by: Neil Chen <[email protected]>

Author: NeilChen93

boards/nxp/frdm_mcxn236/board.c

@@ -324,6 +324,12 @@ void board_early_init_hook(void)
 #endif
 #endif
 
+#if DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(ewm0))
+	CLOCK_SetupOsc32KClocking(kCLOCK_Osc32kToWake);
+	CLOCK_AttachClk(kXTAL32K2_to_EWM0);
+	CLOCK_EnableClock(kCLOCK_Ewm0);
+#endif
+
 	/* Set SystemCoreClock variable. */
 	SystemCoreClock = CLOCK_INIT_CORE_CLOCK;
 }

dts/arm/nxp/nxp_mcxn23x_common.dtsi

@@ -916,6 +916,14 @@
 		program-mem = <0x4000000>;
 		#dma-cells = <0>;
 	};
+
+	ewm0: ewm@C0000 {
+		compatible = "nxp,ewm";
+		reg = <0xC0000 0x6>;
+		status = "disabled";
+		interrupts = <100 0>;
+		clk-divider = <0x0>;
+	};
 };
 
 &systick {

tests/drivers/watchdog/wdt_basic_reset_none/boards/frdm_mcxn236.conf

@@ -0,0 +1,7 @@
+#
+# Copyright 2025 NXP
+#
+# SPDX-License-Identifier Apache-2.0
+#
+CONFIG_TEST_WDT_MAX_WINDOW_TIME=254
+CONFIG_TEST_WDT_SLEEP_TIME=68

tests/drivers/watchdog/wdt_basic_reset_none/boards/frdm_mcxn236.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2025 NXP
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		watchdog0 = &ewm0;
+	};
+};
+
+&ewm0 {
+	status = "okay";
+};