1 # SPDX-License-Identifier: GPL-2.0-only
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/i2c/i2c-mux
5 $schema: http://devicetree.org/meta-schemas/co
6
7 title: GPIO-based I2C Bus Mux
8
9 maintainers:
10 - Wolfram Sang <wsa@kernel.org>
11
12 description: |
13 This binding describes an I2C bus multiplexe
14
15 +-----+ +--
16 | dev | | d
17 +------------+ +-----+ +--
18 | SoC | |
19 | | /--------+--------
20 | +------+ | +------+ child bus A, o
21 | | I2C |-|--| Mux |
22 | +------+ | +--+---+ child bus B, o
23 | | | \----------+------
24 | +------+ | | |
25 | | GPIO |-|-----+ +-----+ +
26 | +------+ | | dev | |
27 +------------+ +-----+ +
28
29 For each I2C child node, an I2C child bus wi
30 order in the device tree.
31
32 Whenever an access is made to a device on a
33 property will be output using the list of GP
34 significant value.
35
36 If an idle state is defined, using the idle-
37 being made to a device on a child bus, the G
38
39 If an idle state is not defined, the most re
40 hardware whenever no access is being made to
41
42 properties:
43 compatible:
44 const: i2c-mux-gpio
45
46 i2c-parent:
47 description: phandle of the I2C bus that t
48 $ref: /schemas/types.yaml#/definitions/pha
49
50 mux-gpios:
51 description: list of GPIOs used to control
52 minItems: 1
53 maxItems: 4 # Should be enough
54
55 idle-state:
56 description: Value to set the muxer to whe
57 last value used.
58 $ref: /schemas/types.yaml#/definitions/uin
59
60 settle-time-us:
61 description: Delay to wait before doing an
62
63 allOf:
64 - $ref: i2c-mux.yaml
65
66 unevaluatedProperties: false
67
68 required:
69 - compatible
70 - i2c-parent
71 - mux-gpios
72
73 examples:
74 - |
75 i2cmux {
76 compatible = "i2c-mux-gpio";
77 #address-cells = <1>;
78 #size-cells = <0>;
79 mux-gpios = <&gpio1 22 0>, <&gpio1 23 0>
80 i2c-parent = <&i2c1>;
81
82 i2c@1 {
83 reg = <1>;
84 #address-cells = <1>;
85 #size-cells = <0>;
86
87 ssd1307: oled@3c {
88 compatible = "solomon,ssd1307fb-i2c"
89 reg = <0x3c>;
90 pwms = <&pwm 4 3000>;
91 reset-gpios = <&gpio2 7 1>;
92 };
93 };
94
95 i2c@3 {
96 reg = <3>;
97 #address-cells = <1>;
98 #size-cells = <0>;
99
100 pca9555: pca9555@20 {
101 compatible = "nxp,pca9555";
102 gpio-controller;
103 #gpio-cells = <2>;
104 reg = <0x20>;
105 };
106 };
107 };
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