--- .../devicetree/bindings/i2c/i2c-mux-simple.txt | 91 ++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-simple.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-simple.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-simple.txt new file mode 100644 index 000000000000..fec1ab39ad64 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-simple.txt @@ -0,0 +1,91 @@ +Simple I2C Bus Mux + +This binding describes an I2C bus multiplexer that uses GPIOs to +route the I2C signals. + + .-----. .-----. + | dev | | dev | + .------------. '-----' '-----' + | SoC | | | + | | .--------+--------' + | .------. | .------+ child bus A, on MUX value set to 0 + | | I2C |-|--| Mux | + | '------' | '--+---+ child bus B, on MUX value set to 1 + | .------. | | '----------+--------+--------. + | | MUX- | | | | | | + | | Ctrl |-|-----+ .-----. .-----. .-----. + | '------' | | dev | | dev | | dev | + '------------' '-----' '-----' '-----' + +Required properties: +- compatible: i2c-mux-simple,mux-locked or i2c-mux-simple,parent-locked +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side + port is connected to. +- control-muxes : Node of the multiplexer that controls "Mux". +- control-mux-names : Should be "mux". +* Standard I2C mux properties. See i2c-mux.txt in this directory. +* I2C child bus nodes. See i2c-mux.txt in this directory. + +Optional properties: +- idle-state: value to set the muxer to when idle. When no value is + given, it defaults to the last value used. + +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 fed to the mux controller. + +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 +mux controller 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. + +Example: + control_i2c_mux: control-i2c-mux { + compatible = "mux-gpio"; + + mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>, + <&pioA 1 GPIO_ACTIVE_HIGH>; + }; + + i2c-mux { + compatible = "i2c-mux-simple,mux-locked"; + i2c-parent = <&i2c1>; + + control-muxes = <&control_i2c_mux>; + control-mux-names = "mux"; + + #address-cells = <1>; + #size-cells = <0>; + + 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>; + reset-active-low; + }; + }; + + i2c@3 { + reg = <3>; + #address-cells = <1>; + #size-cells = <0>; + + pca9555: pca9555@20 { + compatible = "nxp,pca9555"; + gpio-controller; + #gpio-cells = <2>; + reg = <0x20>; + }; + }; + }; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html