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>
---
 .../devicetree/bindings/i2c/silabs,cp2112.yaml     | 107 +++++++++++++++++++++
 1 file changed, 107 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/silabs,cp2112.yaml b/Documentation/devicetree/bindings/i2c/silabs,cp2112.yaml
new file mode 100644
index 000000000000..4b5c1af3673d
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/silabs,cp2112.yaml
@@ -0,0 +1,107 @@
+# 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
+    $ref: /schemas/i2c/i2c-controller.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      sda-gpios:
+        maxItems: 1
+
+      scl-gpios:
+        maxItems: 1
+
+      clock-frequency:
+        minimum: 10000
+        default: 100000
+        maximum: 400000
+
+patternProperties:
+  "-hog(-[0-9]+)?$":
+    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>;
+          };
+        };
+
+      };
+    };

-- 
2.25.1

On Wed, Nov 26, 2025 at 11:05:24AM -0600, Danny Kaehn wrote:
> +  i2c:
> +    description: The SMBus/I2C controller node for the CP2112
> +    $ref: /schemas/i2c/i2c-controller.yaml#
> +    unevaluatedProperties: false
> +
> +    properties:
> +      sda-gpios:
> +        maxItems: 1
> +
> +      scl-gpios:
> +        maxItems: 1

Neither scl nor sda-gpios are needed, they are allowed by i2c-controller
schema, so drop.

> +
> +      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";

Please align the next line with opening ". See also DTS coding style.

> +
> +        fan-rst-hog {
> +            gpio-hog;
> +            gpios = <7 GPIO_ACTIVE_HIGH>;
> +            output-high;
> +            line-name = "FAN_RST";
> +        };
> +
> +        i2c {
> +          #address-cells = <1>;

Messed indentation, stick to one, preferred is 4 spaces for the example.

> +          #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>;
> +          };
> +        };
> +

Drop blank line

> +      };
> +    };
> 
> -- 
> 2.25.1
>