dt-bindings: rtc: Add pinctrl for S35390A

Synology NAS devices use the output pin for interrupt signal 1 to wake up
the system.

Move devicetree bindings for sii,s35390a into its own file.
Add necessary properties to configure the individual pins via pinctrl,
which allows the interrupt signal 1 to be used for wakeup alarm.

Signed-off-by: Markus Probst <markus.probst@posteo.de>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260930-rtc_s35390a_int1-v10-1-e7b1cbc50a7b@posteo.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/sii,s35390a.yaml

@@ -0,0 +1,118 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/sii,s35390a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: S-35390A 2-wire real-time clock
+
+maintainers:
+  - Markus Probst <markus.probst@posteo.de>
+
+description:
+  The S-35390A is a CMOS 2-wire real-time clock IC which operates with the
+  very low current consumption in the wide range of operation voltage.
+
+allOf:
+  - $ref: rtc.yaml#
+
+properties:
+  compatible:
+    const: sii,s35390a
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+    description: Supports up to 2 interrupt lines via the INT1 and INT2 pins.
+
+  interrupt-names:
+    minItems: 1
+    maxItems: 2
+    items:
+      enum:
+        - int1
+        - int2
+
+  wakeup-parent: true
+
+  wakeup-source: true
+
+  "#clock-cells":
+    const: 1
+
+patternProperties:
+  "^pins":
+    type: object
+    additionalProperties: false
+
+    patternProperties:
+      "-pins$":
+        $ref: /schemas/pinctrl/pinmux-node.yaml#
+        additionalProperties: false
+
+        properties:
+          pins:
+            minItems: 1
+            items:
+              enum:
+                - int1
+                - int2
+
+          function:
+            description: |
+              Pin function:
+              - ignore:  Preserve the previous state.
+              - disable: Disable pin output.
+              - wakeup:  Output wakes up the system.
+              - clock:   Output clock pulse.
+              - pmin1:   Minute periodical output with 50% duty.
+              - pmin2:   Minute periodical output L for 7.81 ms.
+                         Can only be used with pin int1.
+            enum:
+              - ignore
+              - disable
+              - wakeup
+              - clock
+              - pmin1
+              - pmin2
+
+        required:
+          - pins
+          - function
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        rtc@30 {
+            compatible = "sii,s35390a";
+            reg = <0x30>;
+            pinctrl-0 = <&rtc_pins_default>;
+            pinctrl-names = "default";
+
+            interrupt-names = "int1";
+            interrupts = <23>;
+
+            rtc_pins_default: pins {
+              int1-pins {
+                pins = "int1";
+                function = "wakeup";
+              };
+              int2-pins {
+                pins = "int2";
+                function = "disable";
+              };
+            };
+        };
+    };

Documentation/devicetree/bindings/rtc/trivial-rtc.yaml

@@ -81,8 +81,6 @@ properties:
       - ricoh,rv5c386
       # I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
       - ricoh,rv5c387a
-      # 2-wire CMOS real-time clock
-      - sii,s35390a
       # ST SPEAr Real-time Clock
       - st,spear600-rtc
       # VIA/Wondermedia VT8500 Real-time Clock