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Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml')
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diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml new file mode 100644 index 000000000..b6af924de --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml @@ -0,0 +1,123 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-mux-gpmux.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: General Purpose I2C Bus Mux + +maintainers: + - Peter Rosin <peda@axentia.se> + +description: |+ + This binding describes an I2C bus multiplexer that uses a mux controller + from the mux subsystem 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 | + '------------' '-----' '-----' '-----' + + +allOf: + - $ref: /schemas/i2c/i2c-mux.yaml# + +properties: + compatible: + const: i2c-mux + + i2c-parent: + $ref: /schemas/types.yaml#/definitions/phandle + description: + The phandle of the I2C bus that this multiplexer's master-side port is + connected to. + + mux-controls: + maxItems: 1 + description: + The mux-controller states are the I2C sub-bus numbers. + + mux-locked: + type: boolean + description: | + Explicitly allow unrelated I2C transactions on the parent I2C adapter at + these times: + - during setup of the multiplexer + - between setup of the multiplexer and the child bus I2C transaction + - between the child bus I2C transaction and releasing of the multiplexer + - during releasing of the multiplexer + + However, I2C transactions to devices behind all I2C multiplexers connected + to the same parent adapter that this multiplexer is connected to are blocked + for the full duration of the complete multiplexed I2C transaction (i.e. + including the times covered by the above list). + If mux-locked is not present, the multiplexer is assumed to be parent-locked. + This means that no unrelated I2C transactions are allowed on the parent I2C + adapter for the complete multiplexed I2C transaction. + The properties of mux-locked and parent-locked multiplexers are discussed + in more detail in Documentation/i2c/i2c-topology.rst. + +required: + - compatible + - i2c-parent + - mux-controls + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/gpio/gpio.h> + mux: mux-controller { + compatible = "gpio-mux"; + #mux-control-cells = <0>; + + mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>, + <&pioA 1 GPIO_ACTIVE_HIGH>; + }; + + i2c-mux { + compatible = "i2c-mux"; + mux-locked; + i2c-parent = <&i2c1>; + + mux-controls = <&mux>; + + #address-cells = <1>; + #size-cells = <0>; + + i2c@1 { + reg = <1>; + #address-cells = <1>; + #size-cells = <0>; + + gpio@20 { + compatible = "nxp,pca9555"; + gpio-controller; + #gpio-cells = <2>; + reg = <0x20>; + }; + }; + + i2c@3 { + reg = <3>; + #address-cells = <1>; + #size-cells = <0>; + + gpio@20 { + compatible = "nxp,pca9555"; + gpio-controller; + #gpio-cells = <2>; + reg = <0x20>; + }; + }; + }; +... |