dt-bindings: i2c: Add CP2112 HID USB to SMBus Bridge

This is a USB HID device which includes an I2C controller and 8 GPIO pins.

The binding allows describing the chip's gpio and i2c controller in DT,
with the i2c controller being bound to a subnode named "i2c". This is
intended to be used in configurations where the CP2112 is permanently
connected in hardware.

Signed-off-by: Danny Kaehn <danny.kaehn@plexus.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260127-cp2112-dt-v13-1-6448ddd4bf22@plexus.com

Author: kaehnd

Documentation/devicetree/bindings/i2c/silabs,cp2112.yaml

@@ -0,0 +1,100 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/silabs,cp2112.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CP2112 HID USB to SMBus/I2C Bridge
+
+maintainers:
+  - Danny Kaehn <danny.kaehn@plexus.com>
+
+description:
+  The CP2112 is a USB HID device which includes an integrated I2C controller
+  and 8 GPIO pins. Its GPIO pins can each be configured as inputs, open-drain
+  outputs, or push-pull outputs.
+
+properties:
+  compatible:
+    const: usb10c4,ea90
+
+  reg:
+    maxItems: 1
+    description: The USB port number
+
+  interrupt-controller: true
+  "#interrupt-cells":
+    const: 2
+
+  gpio-controller: true
+  "#gpio-cells":
+    const: 2
+
+  gpio-line-names:
+    minItems: 1
+    maxItems: 8
+
+  i2c:
+    description: The SMBus/I2C controller node for the CP2112
+    $ref: /schemas/i2c/i2c-controller.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      clock-frequency:
+        minimum: 10000
+        default: 100000
+        maximum: 400000
+
+patternProperties:
+  "-hog(-[0-9]+)?$":
+    type: object
+
+    required:
+      - gpio-hog
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+
+    usb {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        cp2112: device@1 {
+            compatible = "usb10c4,ea90";
+            reg = <1>;
+
+            gpio-controller;
+            interrupt-controller;
+            #interrupt-cells = <2>;
+            #gpio-cells = <2>;
+            gpio-line-names = "CP2112_SDA", "CP2112_SCL", "TEST2",
+                              "TEST3","TEST4", "TEST5", "TEST6";
+
+            fan-rst-hog {
+                gpio-hog;
+                gpios = <7 GPIO_ACTIVE_HIGH>;
+                output-high;
+                line-name = "FAN_RST";
+            };
+
+            i2c {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                sda-gpios = <&cp2112 0 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+                scl-gpios = <&cp2112 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+
+                temp@48 {
+                    compatible = "national,lm75";
+                    reg = <0x48>;
+                };
+            };
+        };
+    };