xref: /linux/Documentation/devicetree/bindings/spi/spi-mux.yaml (revision 205a7309cccd34ad49c2b6b1b59b907c12395d6c) 
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