bindings/i2c/i2c-mux-gpio.yaml

1 # SPDX-License-Identifier: GPL-2.0-only
3 ---
4 $id: http://devicetree.org/schemas/i2c/i2c-mux-gpio.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: GPIO-based I2C Bus Mux
10   - Wolfram Sang <wsa@kernel.org>
13   This binding describes an I2C bus multiplexer that uses GPIOs to route the I2C signals.
15                                   +-----+  +-----+
17     +------------+                +-----+  +-----+
19     |            |          /--------+--------+
20     |   +------+ |  +------+    child bus A, on GPIO value set to 0
21     |   | I2C  |-|--| Mux  |
22     |   +------+ |  +--+---+    child bus B, on GPIO value set to 1
23     |            |     |    \----------+--------+--------+
24     |   +------+ |     |               |        |        |
25     |   | GPIO |-|-----+            +-----+  +-----+  +-----+
26     |   +------+ |                  | dev |  | dev |  | dev |
27     +------------+                  +-----+  +-----+  +-----+
32   Whenever an access is made to a device on a child bus, the value set in the relevant node's reg
33   property will be output using the list of GPIOs, the first in the list holding the least-
36   If an idle state is defined, using the idle-state (optional) property, whenever an access is not
37   being made to a device on a child bus, the GPIOs will be set according to the idle value.
44     const: i2c-mux-gpio
46   i2c-parent:
47     description: phandle of the I2C bus that this multiplexer's master-side port is connected to
50   mux-gpios:
51     description: list of GPIOs used to control the muxer
55   idle-state:
56     description: Value to set the muxer to when idle. When no value is given, it defaults to the
60   settle-time-us:
64   - $ref: i2c-mux.yaml
69   - compatible
70   - i2c-parent
71   - mux-gpios
74   - |
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>;
84         #address-cells = <1>;
85         #size-cells = <0>;
88           compatible = "solomon,ssd1307fb-i2c";
91           reset-gpios = <&gpio2 7 1>;
97         #address-cells = <1>;
98         #size-cells = <0>;
102           gpio-controller;
103           #gpio-cells = <2>;