dt-bindings: rtc: max31335: add max31335 bindings

Document the Analog Devices MAX31335 device tree bindings.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20231120120114.48657-1-antoniu.miclaus@analog.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/adi,max31335.yaml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/adi,max31335.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX31335 RTC
+
+maintainers:
+  - Antoniu Miclaus <antoniu.miclaus@analog.com>
+
+description:
+  Analog Devices MAX31335 I2C RTC ±2ppm Automotive Real-Time Clock with
+  Integrated MEMS Resonator.
+
+allOf:
+  - $ref: rtc.yaml#
+
+properties:
+  compatible:
+    const: adi,max31335
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  "#clock-cells":
+    description:
+      RTC can be used as a clock source through its clock output pin.
+    const: 0
+
+  adi,tc-diode:
+    description:
+      Select the diode configuration for the trickle charger.
+      schottky - Schottky diode in series.
+      standard+schottky - standard diode + Schottky diode in series.
+    enum: [schottky, standard+schottky]
+
+  trickle-resistor-ohms:
+    description:
+      Selected resistor for trickle charger. Should be specified if trickle
+      charger should be enabled.
+    enum: [3000, 6000, 11000]
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        rtc@68 {
+            compatible = "adi,max31335";
+            reg = <0x68>;
+            pinctrl-0 = <&rtc_nint_pins>;
+            interrupts-extended = <&gpio1 16 IRQ_TYPE_LEVEL_HIGH>;
+            aux-voltage-chargeable = <1>;
+            trickle-resistor-ohms = <6000>;
+            adi,tc-diode = "schottky";
+        };
+    };
+...