rtc: rtc7301: Rewrite bindings in schema

This rewrites the Epson RTC7301 bindings to use YAML schema,
and adds a property for "reg-io-width" as used in several
other bindings to account for different register strides.

The USRobotics USR8200 uses the byte IO width.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Link: https://lore.kernel.org/r/20231010-rtc-7301-regwidth-v3-1-ade586b62794@linaro.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/epson,rtc7301.txt

@@ -1,16 +0,0 @@
-EPSON TOYOCOM RTC-7301SF/DG
-
-Required properties:
-
-- compatible: Should be "epson,rtc7301sf" or "epson,rtc7301dg"
-- reg: Specifies base physical address and size of the registers.
-- interrupts: A single interrupt specifier.
-
-Example:
-
-rtc: rtc@44a00000 {
-	compatible = "epson,rtc7301dg";
-	reg = <0x44a00000 0x10000>;
-	interrupt-parent = <&axi_intc_0>;
-	interrupts = <3 2>;
-};

Documentation/devicetree/bindings/rtc/epson,rtc7301.yaml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/epson,rtc7301.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Epson Toyocom RTC-7301SF/DG
+
+description:
+  The only difference between the two variants is the packaging.
+  The DG variant is a DIL package, and the SF variant is a flat
+  package.
+
+maintainers:
+  - Akinobu Mita <akinobu.mita@gmail.com>
+
+properties:
+  compatible:
+    enum:
+      - epson,rtc7301dg
+      - epson,rtc7301sf
+
+  reg:
+    maxItems: 1
+
+  reg-io-width:
+    description:
+      The size (in bytes) of the IO accesses that should be performed
+      on the device.
+    enum: [1, 4]
+    default: 4
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    rtc: rtc@44a00000 {
+        compatible = "epson,rtc7301dg";
+        reg = <0x44a00000 0x10000>;
+        reg-io-width = <4>;
+        interrupt-parent = <&axi_intc_0>;
+        interrupts = <3 2>;
+    };