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
  35 maintainers:
  36   - Chris Packham <chris.packham@alliedtelesis.co.nz>
  37
  38 properties:
  39   compatible:
  40     const: spi-mux
  41
  42   mux-controls:
  43     maxItems: 1
  44
  45 required:
  46   - compatible
  47   - reg
  48   - spi-max-frequency
  49   - mux-controls
  50
  51 unevaluatedProperties: false
  52
  53 examples:
  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     };