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+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-mux-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO-based I2C Bus Mux
+
+maintainers:
+ - Wolfram Sang <wsa@kernel.org>
+
+description: |
+ This binding describes an I2C bus multiplexer that uses GPIOs to route the I2C signals.
+
+ +-----+ +-----+
+ | dev | | dev |
+ +------------+ +-----+ +-----+
+ | SoC | | |
+ | | /--------+--------+
+ | +------+ | +------+ child bus A, on GPIO value set to 0
+ | | I2C |-|--| Mux |
+ | +------+ | +--+---+ child bus B, on GPIO value set to 1
+ | | | \----------+--------+--------+
+ | +------+ | | | | |
+ | | GPIO |-|-----+ +-----+ +-----+ +-----+
+ | +------+ | | dev | | dev | | dev |
+ +------------+ +-----+ +-----+ +-----+
+
+ For each I2C child node, an I2C child bus will be created. They will be numbered based on their
+ order in the device tree.
+
+ Whenever an access is made to a device on a child bus, the value set in the relevant node's reg
+ property will be output using the list of GPIOs, the first in the list holding the least-
+ significant value.
+
+ If an idle state is defined, using the idle-state (optional) property, whenever an access is not
+ being made to a device on a child bus, the GPIOs will be set according to the idle value.
+
+ If an idle state is not defined, the most recently used value will be left programmed into
+ hardware whenever no access is being made to a device on a child bus.
+
+properties:
+ compatible:
+ const: i2c-mux-gpio
+
+ i2c-parent:
+ description: phandle of the I2C bus that this multiplexer's master-side port is connected to
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+
+ mux-gpios:
+ description: list of GPIOs used to control the muxer
+ minItems: 1
+ maxItems: 4 # Should be enough
+
+ idle-state:
+ description: Value to set the muxer to when idle. When no value is given, it defaults to the
+ last value used.
+ $ref: "/schemas/types.yaml#/definitions/uint32"
+
+allOf:
+ - $ref: i2c-mux.yaml
+
+unevaluatedProperties: false
+
+required:
+ - compatible
+ - i2c-parent
+ - mux-gpios
+
+examples:
+ - |
+ i2cmux {
+ compatible = "i2c-mux-gpio";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ mux-gpios = <&gpio1 22 0>, <&gpio1 23 0>;
+ i2c-parent = <&i2c1>;
+
+ i2c@1 {
+ reg = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssd1307: oled@3c {
+ compatible = "solomon,ssd1307fb-i2c";
+ reg = <0x3c>;
+ pwms = <&pwm 4 3000>;
+ reset-gpios = <&gpio2 7 1>;
+ };
+ };
+
+ i2c@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pca9555: pca9555@20 {
+ compatible = "nxp,pca9555";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+ };
+ };
+ };