dts: watchdog: atmel: Add sam4l-watchdog

Introduce sam4l-watchdog binding.

Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>

Author: nandojve

dts/arm/atmel/sam4l.dtsi

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 Gerson Fernando Budke <nandojve@gmail.com>
+ * Copyright (c) 2020-2025 Gerson Fernando Budke <nandojve@gmail.com>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -10,6 +10,10 @@
 #include <zephyr/dt-bindings/clock/atmel_sam_pmc.h>
 
 / {
+	aliases {
+		watchdog0 = &wdt;
+	};
+
 	chosen {
 		zephyr,flash-controller = &flashcalw;
 		zephyr,entropy = &trng;
@@ -237,6 +241,14 @@
 			reg = <0x80020c 0xf>;
 			status = "okay";
 		};
+
+		wdt: watchdog@400f0c00 {
+			compatible = "atmel,sam4l-watchdog";
+			reg = <0x400f0c00 0x400>;
+			interrupts = <44 1>;
+			clocks = <&pmc PMC_TYPE_PERIPHERAL 99>;
+			status = "okay";
+		};
 	};
 };
 

dts/bindings/watchdog/atmel,sam4l-watchdog.yaml

@@ -0,0 +1,37 @@
+# Copyright (c) 2024-2025, Gerson Fernando Budke <nandojve@gmail.com>
+# SPDX-License-Identifier: Apache-2.0
+
+description: ATMEL SAM4L watchdog
+
+compatible: "atmel,sam4l-watchdog"
+
+include: base.yaml
+
+properties:
+  reg:
+    required: true
+
+  interrupts:
+    required: true
+
+  clocks:
+    required: true
+
+  clk-source:
+    type: string
+    default: "rcsys"
+    enum:
+      - "rcsys"
+      - "osc32k"
+    description: |
+      Watchdog counter clock source:
+        - rcsys:  115kHz internal System RC oscillator
+        - osc32k: 32kHz clock source
+      Defaults to "rcsys" (hardware reset value) and always enabled source
+
+  lock-mode:
+    type: boolean
+    description: |
+      Lock the watchdog when setup is executed. This provides a write protection
+      to the control register. This mechanism can only be released when a hardware
+      reset happens.