Add device tree binding documentation for the AAEON embedded controller
(MCU). This microcontroller is found on AAEON embedded boards, it is
connected via I2C and  and provides a GPIO control and watchdog timer.

Signed-off-by: Thomas Perrot (Schneider Electric) <redacted>
---
 .../bindings/mfd/aaeon,srg-imx8p-mcu.yaml          | 67 ++++++++++++++++++++++
 MAINTAINERS                                        |  6 ++
 2 files changed, 73 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/aaeon,srg-imx8p-mcu.yaml b/Documentation/devicetree/bindings/mfd/aaeon,srg-imx8p-mcu.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..9d109fb0d53cb2a859f5a908a35611394eb87807
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/aaeon,srg-imx8p-mcu.yaml

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/aaeon,srg-imx8p-mcu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AAEON Embedded Controller
+
+maintainers:
+  - Jérémie Dautheribes <jeremie.dautheribes@bootlin.com>
+  - Thomas Perrot <thomas.perrot@bootlin.com>
+
+description:
+  AAEON embeds a microcontroller on Standard RISC Gateway with ARM i.MX8M Plus
+  Quad-Core boards providing GPIO control and watchdog timer.
+
+  This MCU is connected via I2C bus.
+
+  Its GPIO controller provides 7 GPOs and 12 GPIOs.
+
+  Its watchdog has a fixed maximum hardware heartbeat of 25 seconds and supports
+  a timeout of 240 seconds through automatic pinging.
+  The timeout is not programmable and cannot be changed via device tree properties.
+
+properties:
+  compatible:
+    const: aaeon,srg-imx8p-mcu
+
+  reg:
+    maxItems: 1
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-line-names:
+    minItems: 1
+    maxItems: 19
+
+required:
+  - compatible
+  - reg
+  - gpio-controller
+  - "#gpio-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      aaeon_mcu: embedded-controller@62 {