FreeBSD/Linux Kernel Cross Reference
sys/contrib/device-tree/Bindings/spi/spi-controller.yaml

     # SPDX-License-Identifier: GPL-2.0
     %YAML 1.2
     ---
     $id: http://devicetree.org/schemas/spi/spi-controller.yaml#
     $schema: http://devicetree.org/meta-schemas/core.yaml#
     
     title: SPI Controller Generic Binding
     
     maintainers:
      - Mark Brown <broonie@kernel.org>
    
    description: |
      SPI busses can be described with a node for the SPI controller device
      and a set of child nodes for each SPI slave on the bus. The system SPI
      controller may be described for use in SPI master mode or in SPI slave mode,
      but not for both at the same time.
    
    properties:
      $nodename:
        pattern: "^spi(@.*|-[0-9a-f])*$"
    
      "#address-cells":
        enum: [0, 1]
    
      "#size-cells":
        const: 0
    
      cs-gpios:
        description: |
          GPIOs used as chip selects.
          If that property is used, the number of chip selects will be
          increased automatically with max(cs-gpios, hardware chip selects).
    
          So if, for example, the controller has 4 CS lines, and the
          cs-gpios looks like this
            cs-gpios = <&gpio1 0 0>, <0>, <&gpio1 1 0>, <&gpio1 2 0>;
    
          Then it should be configured so that num_chipselect = 4, with
          the following mapping
            cs0 : &gpio1 0 0
            cs1 : native
            cs2 : &gpio1 1 0
            cs3 : &gpio1 2 0
    
          The second flag of a gpio descriptor can be GPIO_ACTIVE_HIGH (0)
          or GPIO_ACTIVE_LOW(1). Legacy device trees often use 0.
    
          There is a special rule set for combining the second flag of an
          cs-gpio with the optional spi-cs-high flag for SPI slaves.
    
          Each table entry defines how the CS pin is to be physically
          driven (not considering potential gpio inversions by pinmux):
    
          device node     | cs-gpio       | CS pin state active | Note
          ================+===============+=====================+=====
          spi-cs-high     | -             | H                   |
          -               | -             | L                   |
          spi-cs-high     | ACTIVE_HIGH   | H                   |
          -               | ACTIVE_HIGH   | L                   | 1
          spi-cs-high     | ACTIVE_LOW    | H                   | 2
          -               | ACTIVE_LOW    | L                   |
    
          Notes:
          1) Should print a warning about polarity inversion.
             Here it would be wise to avoid and define the gpio as
             ACTIVE_LOW.
          2) Should print a warning about polarity inversion
             because ACTIVE_LOW is overridden by spi-cs-high.
             Should be generally avoided and be replaced by
             spi-cs-high + ACTIVE_HIGH.
    
      num-cs:
        $ref: /schemas/types.yaml#/definitions/uint32
        description:
          Total number of chip selects.
    
      spi-slave:
        $ref: /schemas/types.yaml#/definitions/flag
        description:
          The SPI controller acts as a slave, instead of a master.
    
      slave:
        type: object
    
        properties:
          compatible:
            description:
              Compatible of the SPI device.
    
        required:
          - compatible
    
    patternProperties:
      "^.*@[0-9a-f]+$":
        type: object
        $ref: spi-peripheral-props.yaml
    
        properties:
          spi-cpha:
           $ref: /schemas/types.yaml#/definitions/flag
           description:
             The device requires shifted clock phase (CPHA) mode.
   
         spi-cpol:
           $ref: /schemas/types.yaml#/definitions/flag
           description:
             The device requires inverse clock polarity (CPOL) mode.
   
       required:
         - compatible
         - reg
   
   allOf:
     - if:
         not:
           required:
             - spi-slave
       then:
         properties:
           "#address-cells":
             const: 1
       else:
         properties:
           "#address-cells":
             const: 0
   
   additionalProperties: true
   
   examples:
     - |
       spi@80010000 {
           #address-cells = <1>;
           #size-cells = <0>;
           compatible = "fsl,imx28-spi";
           reg = <0x80010000 0x2000>;
           interrupts = <96>;
           dmas = <&dma_apbh 0>;
           dma-names = "rx-tx";
   
           display@0 {
               compatible = "lg,lg4573";
               spi-max-frequency = <1000000>;
               reg = <0>;
           };
   
           sensor@1 {
               compatible = "bosch,bme680";
               spi-max-frequency = <100000>;
               reg = <1>;
           };
   
           flash@2 {
               compatible = "jedec,spi-nor";
               spi-max-frequency = <50000000>;
               reg = <2>, <3>;
               stacked-memories = /bits/ 64 <0x10000000 0x10000000>;
           };
       };

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