boards: seeed: add PWM support for the XIAO MG24

The onboard LED is now controllable via PWM.

Signed-off-by: Tamas Jozsi <tamas.jozsi@silabs.com>

boards/seeed/xiao_mg24/xiao_mg24-pinctrl.dtsi

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2025 Pete Johanson
+ * Copyright (c) 2025 Silicon Laboratories Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -56,4 +57,12 @@
 			bias-pull-up;
 		};
 	};
+
+	timer0_default: timer0_default {
+		group0 {
+			pins = <TIMER0_CC0_PA7>;
+			drive-push-pull;
+			output-high;
+		};
+	};
 };

boards/seeed/xiao_mg24/xiao_mg24.dts

@@ -1,11 +1,13 @@
 /*
  * Copyright (c) 2025 Pete Johanson
+ * Copyright (c) 2025 Silicon Laboratories Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 /dts-v1/;
 #include <silabs/xg24/efr32mg24b220f1536im48.dtsi>
+#include <zephyr/dt-bindings/pwm/pwm.h>
 #include "xiao_mg24-pinctrl.dtsi"
 #include "seeed_xiao_connector.dtsi"
 
@@ -26,6 +28,7 @@
 	/* These aliases are provided for compatibility with samples */
 	aliases {
 		led0 = &led0;
+		pwm-led0 = &pwm_led0;
 		watchdog0 = &wdog0;
 	};
 
@@ -37,6 +40,25 @@
 			label = "LED 0";
 		};
 	};
+
+	pwmleds {
+		compatible = "pwm-leds";
+
+		pwm_led0: pwm_led_0 {
+			pwms = <&timer0_pwm 0 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
+			label = "PWM LED 0";
+		};
+	};
+};
+
+&timer0 {
+	status = "okay";
+
+	timer0_pwm: pwm {
+		pinctrl-0 = <&timer0_default>;
+		pinctrl-names = "default";
+		status = "okay";
+	};
 };
 
 &cpu0 {