xref: /linux/Documentation/devicetree/bindings/i2c/i2c-mux-reg.yaml (revision 26b8eb8a98c18b2ee4ea76d99fa2b2a5ccbc1b6c) 
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/i2c/i2c-mux-reg.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Register-based I2C Bus Mux
8
9maintainers:
10  - Peter Rosin <peda@axentia.se>
11
12description: |
13  This binding describes an I2C bus multiplexer that uses a single
14  memory-mapped register to route the I2C signals.
15
16  Whenever an access is made to a device on a child bus, the value
17  set in the relevant node's reg property is output to the register.
18
19  If an idle state is defined via the idle-state property, the
20  register is set to that value whenever no access is being made.
21  Otherwise the most recently used value is left programmed.
22
23allOf:
24  - $ref: /schemas/i2c/i2c-mux.yaml#
25
26properties:
27  compatible:
28    const: i2c-mux-reg
29
30  reg:
31    maxItems: 1
32    description: |
33      Offset and size of the register that selects the active child
34      bus, relative to the parent node's address space. The size
35      determines the access width and must be 1, 2, or 4 bytes. If
36      omitted, the platform device's own memory resource is used
37      instead.
38
39  i2c-parent:
40    $ref: /schemas/types.yaml#/definitions/phandle
41    description:
42      Phandle of the I2C bus that this multiplexer's master-side port
43      is connected to.
44
45  little-endian:
46    type: boolean
47    description: Register is accessed in little-endian byte order.
48
49  big-endian:
50    type: boolean
51    description: Register is accessed in big-endian byte order.
52
53  write-only:
54    type: boolean
55    description:
56      Register is write-only; the driver must not read back the
57      current selection.
58
59  idle-state:
60    $ref: /schemas/types.yaml#/definitions/uint32
61    description:
62      Value to write to the register when no child bus is selected.
63
64required:
65  - compatible
66  - i2c-parent
67
68unevaluatedProperties: false
69
70examples:
71  - |
72    i2c-mux@6028 {
73        compatible = "i2c-mux-reg";
74        reg = <0x6028 0x4>;
75        little-endian;
76        #address-cells = <1>;
77        #size-cells = <0>;
78        i2c-parent = <&i2c1>;
79
80        i2c@0 {
81            reg = <0>;
82            #address-cells = <1>;
83            #size-cells = <0>;
84        };
85
86        i2c@1 {
87            reg = <1>;
88            #address-cells = <1>;
89            #size-cells = <0>;
90        };
91    };
92...
93