Add the dt-bindings for the NXP SIUL2 module which is a multi
function device. It can export information about the SoC, configure
the pinmux&pinconf for pins and it is also a GPIO controller with
interrupt capability.

Signed-off-by: Andrei Stefanescu <redacted>
---
 .../bindings/mfd/nxp,s32g2-siul2.yaml         | 163 ++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/nxp,s32g2-siul2.yaml

diff --git a/Documentation/devicetree/bindings/mfd/nxp,s32g2-siul2.yaml b/Documentation/devicetree/bindings/mfd/nxp,s32g2-siul2.yaml
new file mode 100644
index 000000000000..8ae185b4bc78
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/nxp,s32g2-siul2.yaml

@@ -0,0 +1,163 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2024 NXP
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/nxp,s32g2-siul2.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP S32 System Integration Unit Lite2 (SIUL2)
+
+maintainers:
+  - Andrei Stefanescu <andrei.stefanescu@oss.nxp.com>
+
+description: |
+  SIUL2 is a hardware block which implements pinmuxing,
+  pinconf, GPIOs (some with interrupt capability) and
+  registers which contain information about the SoC.
+  There are generally two SIUL2 modules whose functionality
+  is grouped together. For example interrupt configuration
+  registers are part of SIUL2_1 even though interrupts are
+  also available for SIUL2_0 pins.
+
+  The following register types are exported by SIUL2:
+    - MIDR (MCU ID Register) - information related to the SoC
+    - interrupt configuration registers
+    - MSCR (Multiplexed Signal Configuration Register) - pinmuxing and pinconf
+    - IMCR (Input Multiplexed Signal Configuration Register)- pinmuxing
+    - PGPDO (Parallel GPIO Pad Data Out Register) - GPIO output value
+    - PGPDI (Parallel GPIO Pad Data In Register) - GPIO input value
+
+  Most registers are 32bit wide with the exception of PGPDO/PGPDI which are
+  16bit wide.
+
+properties:
+  compatible:
+    oneOf:
+      - const: nxp,s32g2-siul2
+      - items:
+          - enum:
+              - nxp,s32g3-siul2
+          - const: nxp,s32g2-siul2
+
+  reg:
+    minItems: 2