xref: /linux/Documentation/devicetree/bindings/spi/spi-mux.yaml (revision fdd7c7e0d2ab3987882c570612d4622f437292c7) 
1# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/spi/spi-mux.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Generic SPI Multiplexer
8
9description: |
10  This binding describes a SPI bus multiplexer to route the SPI chip select
11  signals. This can be used when you need more devices than the SPI controller
12  has chip selects available. An example setup is shown in ASCII art; the actual
13  setting of the multiplexer to a channel needs to be done by a specific SPI mux
14  driver.
15
16        MOSI /--------------------------------+--------+--------+--------\
17        MISO |/------------------------------+|-------+|-------+|-------\|
18         SCL ||/----------------------------+||------+||------+||------\||
19             |||                            |||      |||      |||      |||
20      +------------+                        |||      |||      |||      |||
21      | SoC  |||   |                      +-+++-+  +-+++-+  +-+++-+  +-+++-+
22      |      |||   |                      | dev |  | dev |  | dev |  | dev |
23      |   +--+++-+ | CS-X  +------+\      +--+--+  +--+--+  +--+--+  +--+--+
24      |   | SPI  +-|-------+ Mux  |\\   CS-0 |        |        |        |
25      |   +------+ |       +--+---+\\\-------/   CS-1 |        |        |
26      |            |          |    \\\----------------/   CS-2 |        |
27      |   +------+ |          |     \\-------------------------/   CS-3 |
28      |   | ?    +-|----------/      \----------------------------------/
29      |   +------+ |
30      +------------+
31
32allOf:
33  - $ref: /schemas/spi/spi-controller.yaml#
34  - $ref: /schemas/spi/spi-peripheral-props.yaml#
35
36maintainers:
37  - Chris Packham <chris.packham@alliedtelesis.co.nz>
38
39properties:
40  compatible:
41    const: spi-mux
42
43  mux-controls:
44    maxItems: 1
45
46required:
47  - compatible
48  - reg
49  - mux-controls
50
51unevaluatedProperties: false
52
53examples:
54  - |
55    #include <dt-bindings/gpio/gpio.h>
56    mux: mux-controller {
57        compatible = "gpio-mux";
58        #mux-control-cells = <0>;
59
60        mux-gpios = <&gpio0 3 GPIO_ACTIVE_HIGH>;
61    };
62
63    spi {
64        #address-cells = <1>;
65        #size-cells = <0>;
66        spi@0 {
67            compatible = "spi-mux";
68            reg = <0>;
69            #address-cells = <1>;
70            #size-cells = <0>;
71            spi-max-frequency = <100000000>;
72
73            mux-controls = <&mux>;
74
75            flash@0 {
76                compatible = "jedec,spi-nor";
77                reg = <0>;
78                spi-max-frequency = <40000000>;
79            };
80
81            sensor@1 {
82                compatible = "bosch,bme680";
83                reg = <1>;
84                spi-max-frequency = <10000000>;
85            };
86        };
87    };
88