| # 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>; |
| }; |
| }; |
| }; |
| ... |
