tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
35maintainers:
36 - Chris Packham <chris.packham@alliedtelesis.co.nz>
37
38properties:
39 compatible:
40 const: spi-mux
41
42 mux-controls:
43 maxItems: 1
44
45required:
46 - compatible
47 - reg
48 - spi-max-frequency
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 spi-flash@0 {
76 compatible = "jedec,spi-nor";
77 reg = <0>;
78 #address-cells = <1>;
79 #size-cells = <0>;
80 spi-max-frequency = <40000000>;
81 };
82
83 spi-device@1 {
84 compatible = "lineartechnology,ltc2488";
85 reg = <1>;
86 #address-cells = <1>;
87 #size-cells = <0>;
88 spi-max-frequency = <10000000>;
89 };
90 };
91 };