linux/Documentation/devicetree/bindings/media/video-interfaces.yaml

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

title: Common bindings for video receiver and transmitter interface endpoints

maintainers:
  - Sakari Ailus <sakari.ailus@linux.intel.com>
  - Laurent Pinchart <laurent.pinchart@ideasonboard.com>

description: |
  Video data pipelines usually consist of external devices, e.g. camera sensors,
  controlled over an I2C, SPI or UART bus, and SoC internal IP blocks, including
  video DMA engines and video data processors.

  SoC internal blocks are described by DT nodes, placed similarly to other SoC
  blocks.  External devices are represented as child nodes of their respective
  bus controller nodes, e.g. I2C.

  Data interfaces on all video devices are described by their child 'port' nodes.
  Configuration of a port depends on other devices participating in the data
  transfer and is described by 'endpoint' subnodes.

  device {
      ...
      ports {
          #address-cells = <1>;
          #size-cells = <0>;

          port@0 {
              ...
              endpoint@0 { ... };
              endpoint@1 { ... };
          };
          port@1 { ... };
      };
  };

  If a port can be configured to work with more than one remote device on the same
  bus, an 'endpoint' child node must be provided for each of them.  If more than
  one port is present in a device node or there is more than one endpoint at a
  port, or port node needs to be associated with a selected hardware interface,
  a common scheme using '#address-cells', '#size-cells' and 'reg' properties is
  used.

  All 'port' nodes can be grouped under optional 'ports' node, which allows to
  specify #address-cells, #size-cells properties independently for the 'port'
  and 'endpoint' nodes and any child device nodes a device might have.

  Two 'endpoint' nodes are linked with each other through their 'remote-endpoint'
  phandles.  An endpoint subnode of a device contains all properties needed for
  configuration of this device for data exchange with other device.  In most
  cases properties at the peer 'endpoint' nodes will be identical, however they
  might need to be different when there is any signal modifications on the bus
  between two devices, e.g. there are logic signal inverters on the lines.

  It is allowed for multiple endpoints at a port to be active simultaneously,
  where supported by a device.  For example, in case where a data interface of
  a device is partitioned into multiple data busses, e.g. 16-bit input port
  divided into two separate ITU-R BT.656 8-bit busses.  In such case bus-width
  and data-shift properties can be used to assign physical data lines to each
  endpoint node (logical bus).

  Documenting bindings for devices
  --------------------------------

  All required and optional bindings the device supports shall be explicitly
  documented in device DT binding documentation. This also includes port and
  endpoint nodes for the device, including unit-addresses and reg properties
  where relevant.

allOf:
  - $ref: /schemas/graph.yaml#/$defs/endpoint-base

properties:
  slave-mode:
    type: boolean
    description:
      Indicates that the link is run in slave mode. The default when this
      property is not specified is master mode. In the slave mode horizontal and
      vertical synchronization signals are provided to the slave device (data
      source) by the master device (data sink). In the master mode the data
      source device is also the source of the synchronization signals.

  bus-type:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum:
      - 1 # MIPI CSI-2 C-PHY
      - 2 # MIPI CSI1
      - 3 # CCP2
      - 4 # MIPI CSI-2 D-PHY
      - 5 # Parallel
      - 6 # BT.656
    description:
      Data bus type.

  bus-width:
    $ref: /schemas/types.yaml#/definitions/uint32
    maximum: 64
    description:
      Number of data lines actively used, valid for the parallel busses.

  data-shift:
    $ref: /schemas/types.yaml#/definitions/uint32
    maximum: 64
    description:
      On the parallel data busses, if bus-width is used to specify the number of
      data lines, data-shift can be used to specify which data lines are used,
      e.g. "bus-width=<8>; data-shift=<2>;" means, that lines 9:2 are used.

  hsync-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Active state of the HSYNC signal, 0/1 for LOW/HIGH respectively.

  vsync-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Active state of the VSYNC signal, 0/1 for LOW/HIGH respectively. Note,
      that if HSYNC and VSYNC polarities are not specified, embedded
      synchronization may be required, where supported.

  data-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Similar to HSYNC and VSYNC, specifies data line polarity.

  data-enable-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Similar to HSYNC and VSYNC, specifies the data enable signal polarity.

  field-even-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Field signal level during the even field data transmission.

  pclk-sample:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Sample data on rising (1) or falling (0) edge of the pixel clock signal.

  sync-on-green-active:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Active state of Sync-on-green (SoG) signal, 0/1 for LOW/HIGH respectively.

  data-lanes:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    minItems: 1
    maxItems: 8
    items:
      # Assume up to 9 physical lane indices
      maximum: 8
    description:
      An array of physical data lane indexes. Position of an entry determines
      the logical lane number, while the value of an entry indicates physical
      lane, e.g. for 2-lane MIPI CSI-2 bus we could have "data-lanes = <1 2>;",
      assuming the clock lane is on hardware lane 0. If the hardware does not
      support lane reordering, monotonically incremented values shall be used
      from 0 or 1 onwards, depending on whether or not there is also a clock
      lane. This property is valid for serial busses only (e.g. MIPI CSI-2).

  clock-lanes:
    $ref: /schemas/types.yaml#/definitions/uint32
    # Assume up to 9 physical lane indices
    maximum: 8
    description:
      Physical clock lane index. Position of an entry determines the logical
      lane number, while the value of an entry indicates physical lane, e.g. for
      a MIPI CSI-2 bus we could have "clock-lanes = <0>;", which places the
      clock lane on hardware lane 0. This property is valid for serial busses
      only (e.g. MIPI CSI-2).

  clock-noncontinuous:
    type: boolean
    description:
      Allow MIPI CSI-2 non-continuous clock mode.

  link-frequencies:
    $ref: /schemas/types.yaml#/definitions/uint64-array
    description:
      Allowed data bus frequencies. For MIPI CSI-2, for instance, this is the
      actual frequency of the bus, not bits per clock per lane value. An array
      of 64-bit unsigned integers.

  lane-polarities:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    minItems: 1
    maxItems: 9
    items:
      enum: [ 0, 1 ]
    description:
      An array of polarities of the lanes starting from the clock lane and
      followed by the data lanes in the same order as in data-lanes. Valid
      values are 0 (normal) and 1 (inverted). The length of the array should be
      the combined length of data-lanes and clock-lanes properties. If the
      lane-polarities property is omitted, the value must be interpreted as 0
      (normal). This property is valid for serial busses only.

  strobe:
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    description:
      Whether the clock signal is used as clock (0) or strobe (1). Used with
      CCP2, for instance.

additionalProperties: true