Documentation/devicetree/bindings/spi/spi-mux.yaml

   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
   7 title: Generic SPI Multiplexer
   8
   9 description: |
  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
  32 allOf:
  33   - $ref: /schemas/spi/spi-controller.yaml#
  34   - $ref: /schemas/spi/spi-peripheral-props.yaml#
  35
  36 maintainers:
  37   - Chris Packham <chris.packham@alliedtelesis.co.nz>
  38
  39 properties:
  40   compatible:
  41     const: spi-mux
  42
  43   mux-controls:
  44     maxItems: 1
  45
  46 required:
  47   - compatible
  48   - reg
  49   - spi-max-frequency
  50   - mux-controls
  51
  52 unevaluatedProperties: false
  53
  54 examples:
  55   - |
  56     #include <dt-bindings/gpio/gpio.h>
  57     mux: mux-controller {
  58         compatible = "gpio-mux";
  59         #mux-control-cells = <0>;
  60
  61         mux-gpios = <&gpio0 3 GPIO_ACTIVE_HIGH>;
  62     };
  63
  64     spi {
  65         #address-cells = <1>;
  66         #size-cells = <0>;
  67         spi@0 {
  68             compatible = "spi-mux";
  69             reg = <0>;
  70             #address-cells = <1>;
  71             #size-cells = <0>;
  72             spi-max-frequency = <100000000>;
  73
  74             mux-controls = <&mux>;
  75
  76             flash@0 {
  77                 compatible = "jedec,spi-nor";
  78                 reg = <0>;
  79                 spi-max-frequency = <40000000>;
  80             };
  81
  82             sensor@1 {
  83                 compatible = "bosch,bme680";
  84                 reg = <1>;
  85                 spi-max-frequency = <10000000>;
  86             };
  87         };
  88     };