dt-bindings: input: Add Cirrus EP93xx keypad

Add YAML bindings for ep93xx SoC keypad.
Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Tested-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/input/cirrus,ep9307-keypad.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/cirrus,ep9307-keypad.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Cirrus ep93xx keypad
+
+maintainers:
+  - Alexander Sverdlin <alexander.sverdlin@gmail.com>
+
+allOf:
+  - $ref: /schemas/input/matrix-keymap.yaml#
+
+description:
+  The KPP is designed to interface with a keypad matrix with 2-point contact
+  or 3-point contact keys. The KPP is designed to simplify the software task
+  of scanning a keypad matrix. The KPP is capable of detecting, debouncing,
+  and decoding one or multiple keys pressed simultaneously on a keypad.
+
+properties:
+  compatible:
+    oneOf:
+      - const: cirrus,ep9307-keypad
+      - items:
+          - enum:
+              - cirrus,ep9312-keypad
+              - cirrus,ep9315-keypad
+          - const: cirrus,ep9307-keypad
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  debounce-delay-ms:
+    description: |
+          Time in microseconds that key must be pressed or
+          released for state change interrupt to trigger.
+
+  cirrus,prescale:
+    description: row/column counter pre-scaler load value
+    $ref: /schemas/types.yaml#/definitions/uint16
+    maximum: 1023
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - linux,keymap
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/input/input.h>
+    #include <dt-bindings/clock/cirrus,ep9301-syscon.h>
+    keypad@800f0000 {
+        compatible = "cirrus,ep9307-keypad";
+        reg = <0x800f0000 0x0c>;
+        interrupt-parent = <&vic0>;
+        interrupts = <29>;
+        clocks = <&eclk EP93XX_CLK_KEYPAD>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&keypad_default_pins>;
+        linux,keymap = <KEY_UP>,
+                       <KEY_DOWN>,
+                       <KEY_VOLUMEDOWN>,
+                       <KEY_HOME>,
+                       <KEY_RIGHT>,
+                       <KEY_LEFT>,
+                       <KEY_ENTER>,
+                       <KEY_VOLUMEUP>,
+                       <KEY_F6>,
+                       <KEY_F8>,
+                       <KEY_F9>,
+                       <KEY_F10>,
+                       <KEY_F1>,
+                       <KEY_F2>,
+                       <KEY_F3>,
+                       <KEY_POWER>;
+    };