| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | %YAML 1.2 |
| 3 | --- |
| 4 | $id: http://devicetree.org/schemas/i2c/i2c-mux-pinctrl.yaml# |
| 5 | $schema: http://devicetree.org/meta-schemas/core.yaml# |
| 6 | |
| 7 | title: Pinctrl-based I2C Bus Mux |
| 8 | |
| 9 | maintainers: |
| 10 | - Wolfram Sang <wsa@kernel.org> |
| 11 | |
| 12 | description: | |
| 13 | This binding describes an I2C bus multiplexer that uses pin multiplexing to route the I2C |
| 14 | signals, and represents the pin multiplexing configuration using the pinctrl device tree |
| 15 | bindings. |
| 16 | |
| 17 | +-----+ +-----+ |
| 18 | | dev | | dev | |
| 19 | +------------------------+ +-----+ +-----+ |
| 20 | | SoC | | | |
| 21 | | /----|------+--------+ |
| 22 | | +---+ +------+ | child bus A, on first set of pins |
| 23 | | |I2C|---|Pinmux| | |
| 24 | | +---+ +------+ | child bus B, on second set of pins |
| 25 | | \----|------+--------+--------+ |
| 26 | | | | | | |
| 27 | +------------------------+ +-----+ +-----+ +-----+ |
| 28 | | dev | | dev | | dev | |
| 29 | +-----+ +-----+ +-----+ |
| 30 | |
| 31 | For each named state defined in the pinctrl-names property, an I2C child bus will be created. |
| 32 | I2C child bus numbers are assigned based on the index into the pinctrl-names property. |
| 33 | |
| 34 | The only exception is that no bus will be created for a state named "idle". If such a state is |
| 35 | defined, it must be the last entry in pinctrl-names. For example: |
| 36 | |
| 37 | pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1 |
| 38 | pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last) |
| 39 | pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last) |
| 40 | |
| 41 | Whenever an access is made to a device on a child bus, the relevant pinctrl state will be |
| 42 | programmed into hardware. |
| 43 | |
| 44 | If an idle state is defined, whenever an access is not being made to a device on a child bus, |
| 45 | the idle pinctrl state will be programmed into hardware. |
| 46 | |
| 47 | If an idle state is not defined, the most recently used pinctrl state will be left programmed |
| 48 | into hardware whenever no access is being made of a device on a child bus. |
| 49 | |
| 50 | properties: |
| 51 | compatible: |
| 52 | const: i2c-mux-pinctrl |
| 53 | |
| 54 | i2c-parent: |
| 55 | $ref: /schemas/types.yaml#/definitions/phandle |
| 56 | description: The phandle of the I2C bus that this multiplexer's master-side port is connected |
| 57 | to. |
| 58 | |
| 59 | allOf: |
| 60 | - $ref: i2c-mux.yaml |
| 61 | |
| 62 | unevaluatedProperties: false |
| 63 | |
| 64 | required: |
| 65 | - compatible |
| 66 | - i2c-parent |
| 67 | |
| 68 | examples: |
| 69 | - | |
| 70 | i2cmux { |
| 71 | compatible = "i2c-mux-pinctrl"; |
| 72 | #address-cells = <1>; |
| 73 | #size-cells = <0>; |
| 74 | |
| 75 | i2c-parent = <&i2c1>; |
| 76 | |
| 77 | pinctrl-names = "ddc", "pta", "idle"; |
| 78 | pinctrl-0 = <&state_i2cmux_ddc>; |
| 79 | pinctrl-1 = <&state_i2cmux_pta>; |
| 80 | pinctrl-2 = <&state_i2cmux_idle>; |
| 81 | |
| 82 | i2c@0 { |
| 83 | reg = <0>; |
| 84 | #address-cells = <1>; |
| 85 | #size-cells = <0>; |
| 86 | |
| 87 | eeprom@50 { |
| 88 | compatible = "atmel,24c02"; |
| 89 | reg = <0x50>; |
| 90 | }; |
| 91 | }; |
| 92 | |
| 93 | i2c@1 { |
| 94 | reg = <1>; |
| 95 | #address-cells = <1>; |
| 96 | #size-cells = <0>; |
| 97 | |
| 98 | eeprom@50 { |
| 99 | compatible = "atmel,24c02"; |
| 100 | reg = <0x50>; |
| 101 | }; |
| 102 | }; |
| 103 | }; |