dt-bindings: input: ti,twl4030-keypad: convert to DT schema

Convert the legacy TXT binding for the TWL4030 keypad module
to the modern YAML DT schema format. This adds formal validation
and improves documentation by inheriting from the matrix-keymap schema.

Signed-off-by: Jihed Chaibi <jihed.chaibi.dev@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250819222823.157943-1-jihed.chaibi.dev@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: JihedChaibi

Documentation/devicetree/bindings/input/ti,twl4030-keypad.yaml

@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/ti,twl4030-keypad.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments TWL4030-family Keypad Controller
+
+maintainers:
+  - Peter Ujfalusi <peter.ujfalusi@gmail.com>
+
+description:
+  TWL4030's Keypad controller is used to interface a SoC with a matrix-type
+  keypad device. The keypad controller supports multiple row and column lines.
+  A key can be placed at each intersection of a unique row and a unique column.
+  The keypad controller can sense a key-press and key-release and report the
+  event using a interrupt to the cpu.
+
+allOf:
+  - $ref: matrix-keymap.yaml#
+
+properties:
+  compatible:
+    const: ti,twl4030-keypad
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - interrupts
+  - keypad,num-rows
+  - keypad,num-columns
+  - linux,keymap
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/input/input.h>
+
+    keypad {
+        compatible = "ti,twl4030-keypad";
+        interrupts = <1>;
+        keypad,num-rows = <8>;
+        keypad,num-columns = <8>;
+        linux,keymap = <
+            /* row 0 */
+            MATRIX_KEY(0, 0, KEY_1)
+            MATRIX_KEY(0, 1, KEY_2)
+            MATRIX_KEY(0, 2, KEY_3)
+
+            /* ...and so on for a full 8x8 matrix... */
+
+            /* row 7 */
+            MATRIX_KEY(7, 6, KEY_Y)
+            MATRIX_KEY(7, 7, KEY_Z)
+        >;
+    };