| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0 |
| 2 | %YAML 1.2 |
| 3 | --- |
| 4 | $id: http://devicetree.org/schemas/i2c/i2c-mux-gpmux.yaml# |
| 5 | $schema: http://devicetree.org/meta-schemas/core.yaml# |
| 6 | |
| 7 | title: General Purpose I2C Bus Mux |
| 8 | |
| 9 | maintainers: |
| 10 | - Peter Rosin <peda@axentia.se> |
| 11 | |
| 12 | description: |+ |
| 13 | This binding describes an I2C bus multiplexer that uses a mux controller |
| 14 | from the mux subsystem to route the I2C signals. |
| 15 | |
| 16 | .-----. .-----. |
| 17 | | dev | | dev | |
| 18 | .------------. '-----' '-----' |
| 19 | | SoC | | | |
| 20 | | | .--------+--------' |
| 21 | | .------. | .------+ child bus A, on MUX value set to 0 |
| 22 | | | I2C |-|--| Mux | |
| 23 | | '------' | '--+---+ child bus B, on MUX value set to 1 |
| 24 | | .------. | | '----------+--------+--------. |
| 25 | | | MUX- | | | | | | |
| 26 | | | Ctrl |-|-----+ .-----. .-----. .-----. |
| 27 | | '------' | | dev | | dev | | dev | |
| 28 | '------------' '-----' '-----' '-----' |
| 29 | |
| 30 | |
| 31 | allOf: |
| 32 | - $ref: /schemas/i2c/i2c-mux.yaml# |
| 33 | |
| 34 | properties: |
| 35 | compatible: |
| 36 | const: i2c-mux |
| 37 | |
| 38 | i2c-parent: |
| 39 | $ref: /schemas/types.yaml#/definitions/phandle |
| 40 | description: |
| 41 | The phandle of the I2C bus that this multiplexer's master-side port is |
| 42 | connected to. |
| 43 | |
| 44 | mux-controls: |
| 45 | maxItems: 1 |
| 46 | description: |
| 47 | The mux-controller states are the I2C sub-bus numbers. |
| 48 | |
| 49 | mux-locked: |
| 50 | type: boolean |
| 51 | description: | |
| 52 | Explicitly allow unrelated I2C transactions on the parent I2C adapter at |
| 53 | these times: |
| 54 | - during setup of the multiplexer |
| 55 | - between setup of the multiplexer and the child bus I2C transaction |
| 56 | - between the child bus I2C transaction and releasing of the multiplexer |
| 57 | - during releasing of the multiplexer |
| 58 | |
| 59 | However, I2C transactions to devices behind all I2C multiplexers connected |
| 60 | to the same parent adapter that this multiplexer is connected to are blocked |
| 61 | for the full duration of the complete multiplexed I2C transaction (i.e. |
| 62 | including the times covered by the above list). |
| 63 | If mux-locked is not present, the multiplexer is assumed to be parent-locked. |
| 64 | This means that no unrelated I2C transactions are allowed on the parent I2C |
| 65 | adapter for the complete multiplexed I2C transaction. |
| 66 | The properties of mux-locked and parent-locked multiplexers are discussed |
| 67 | in more detail in Documentation/i2c/i2c-topology.rst. |
| 68 | |
| 69 | required: |
| 70 | - compatible |
| 71 | - i2c-parent |
| 72 | - mux-controls |
| 73 | |
| 74 | unevaluatedProperties: false |
| 75 | |
| 76 | examples: |
| 77 | - | |
| 78 | #include <dt-bindings/gpio/gpio.h> |
| 79 | mux: mux-controller { |
| 80 | compatible = "gpio-mux"; |
| 81 | #mux-control-cells = <0>; |
| 82 | |
| 83 | mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>, |
| 84 | <&pioA 1 GPIO_ACTIVE_HIGH>; |
| 85 | }; |
| 86 | |
| 87 | i2c-mux { |
| 88 | compatible = "i2c-mux"; |
| 89 | mux-locked; |
| 90 | i2c-parent = <&i2c1>; |
| 91 | |
| 92 | mux-controls = <&mux>; |
| 93 | |
| 94 | #address-cells = <1>; |
| 95 | #size-cells = <0>; |
| 96 | |
| 97 | i2c@1 { |
| 98 | reg = <1>; |
| 99 | #address-cells = <1>; |
| 100 | #size-cells = <0>; |
| 101 | |
| 102 | gpio@20 { |
| 103 | compatible = "nxp,pca9555"; |
| 104 | gpio-controller; |
| 105 | #gpio-cells = <2>; |
| 106 | reg = <0x20>; |
| 107 | }; |
| 108 | }; |
| 109 | |
| 110 | i2c@3 { |
| 111 | reg = <3>; |
| 112 | #address-cells = <1>; |
| 113 | #size-cells = <0>; |
| 114 | |
| 115 | gpio@20 { |
| 116 | compatible = "nxp,pca9555"; |
| 117 | gpio-controller; |
| 118 | #gpio-cells = <2>; |
| 119 | reg = <0x20>; |
| 120 | }; |
| 121 | }; |
| 122 | }; |
| 123 | ... |