dt-bindings: rtc: Document NVIDIA VRS RTC

Add device tree bindings for NVIDIA VRS (Voltage Regulator Specification)
RTC device. NVIDIA VRS is a Power Management IC (PMIC) that implements a
power sequencing solution with I2C interface. The device includes RTC
which provides functionality to get/set system time, retain system
time across boot, wake system from suspend and shutdown state.

Supported platforms:
- NVIDIA Jetson AGX Orin Developer Kit
- NVIDIA IGX Orin Development Kit
- NVIDIA Jetson Orin NX Developer Kit
- NVIDIA Jetson Orin Nano Developer Kit

Signed-off-by: Shubhi Garg <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: Jon Hunter <[e-mail]>
Tested-by: Jon Hunter <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

Documentation/devicetree/bindings/rtc/nvidia,vrs-10.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/nvidia,vrs-10.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Voltage Regulator Specification Real Time Clock
+
+maintainers:
+  - Shubhi Garg <[e-mail]>
+
+description:
+  NVIDIA VRS-10 (Voltage Regulator Specification) is a Power Management IC
+  (PMIC) that implements a power sequencing solution with I2C interface.
+  The device includes a real-time clock (RTC) with 32kHz clock output and
+  backup battery support, alarm functionality for system wake-up from
+  suspend and shutdown states, OTP memory for power sequencing configuration,
+  and an interrupt controller for managing VRS events.
+
+properties:
+  compatible:
+    const: nvidia,vrs-10
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - '#interrupt-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        pmic@3c {
+            compatible = "nvidia,vrs-10";
+            reg = <0x3c>;
+            interrupt-parent = <&pmc>;
+            interrupts = <24 IRQ_TYPE_LEVEL_LOW>;
+            interrupt-controller;
+            #interrupt-cells = <2>;
+        };
+    };