linux/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/spi/spi-peripheral-props.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Peripheral-specific properties for a SPI bus.

description:
  Many SPI controllers need to add properties to peripheral devices. They could
  be common properties like spi-max-frequency, spi-cpha, etc. or they could be
  controller specific like delay in clock or data lines, etc. These properties
  need to be defined in the peripheral node because they are per-peripheral and
  there can be multiple peripherals attached to a controller. All those
  properties are listed here. The controller specific properties should go in
  their own separate schema that should be referenced from here.

maintainers:
  - Mark Brown <broonie@kernel.org>

properties:
  reg:
    minItems: 1
    maxItems: 256
    items:
      items:
        - minimum: 0
          maximum: 256
    description:
      Chip select used by the device.

  spi-cs-high:
    $ref: /schemas/types.yaml#/definitions/flag
    description:
      The device requires the chip select active high.

  spi-lsb-first:
    $ref: /schemas/types.yaml#/definitions/flag
    description:
      The device requires the LSB first mode.

  spi-max-frequency:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      Maximum SPI clocking speed of the device in Hz.

  spi-cs-setup-delay-ns:
    description:
      Delay in nanoseconds to be introduced by the controller after CS is
      asserted.

  spi-cs-hold-delay-ns:
    description:
      Delay in nanoseconds to be introduced by the controller before CS is
      de-asserted.

  spi-cs-inactive-delay-ns:
    description:
      Delay in nanoseconds to be introduced by the controller after CS is
      de-asserted.

  spi-rx-bus-width:
    description:
      Bus width to the SPI bus used for read transfers.
      If 0 is provided, then no RX will be possible on this device.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [0, 1, 2, 4, 8]
    default: 1

  spi-rx-delay-us:
    description:
      Delay, in microseconds, after a read transfer.

  rx-sample-delay-ns:
    description: SPI Rx sample delay offset, unit is nanoseconds.
      The delay from the default sample time before the actual
      sample of the rxd input signal occurs.

  spi-tx-bus-width:
    description:
      Bus width to the SPI bus used for write transfers.
      If 0 is provided, then no TX will be possible on this device.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [0, 1, 2, 4, 8]
    default: 1

  spi-tx-delay-us:
    description:
      Delay, in microseconds, after a write transfer.

  stacked-memories:
    description: Several SPI memories can be wired in stacked mode.
      This basically means that either a device features several chip
      selects, or that different devices must be seen as a single
      bigger chip. This basically doubles (or more) the total address
      space with only a single additional wire, while still needing
      to repeat the commands when crossing a chip boundary. The size of
      each chip should be provided as members of the array.
    $ref: /schemas/types.yaml#/definitions/uint64-array
    minItems: 2
    maxItems: 4

  parallel-memories:
    description: Several SPI memories can be wired in parallel mode.
      The devices are physically on a different buses but will always
      act synchronously as each data word is spread across the
      different memories (eg. even bits are stored in one memory, odd
      bits in the other). This basically doubles the address space and
      the throughput while greatly complexifying the wiring because as
      many busses as devices must be wired. The size of each chip should
      be provided as members of the array.
    $ref: /schemas/types.yaml#/definitions/uint64-array
    minItems: 2
    maxItems: 4

  st,spi-midi-ns:
    description: |
      Only for STM32H7, (Master Inter-Data Idleness) minimum time
      delay in nanoseconds inserted between two consecutive data frames.      

# The controller specific properties go here.
allOf:
  - $ref: arm,pl022-peripheral-props.yaml#
  - $ref: cdns,qspi-nor-peripheral-props.yaml#
  - $ref: fsl,dspi-peripheral-props.yaml#
  - $ref: samsung,spi-peripheral-props.yaml#
  - $ref: nvidia,tegra210-quad-peripheral-props.yaml#

additionalProperties: true