xref: /kernel/linux/linux-6.6/Documentation/devicetree/bindings/mtd/raw-nand-chip.yaml

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

title: Raw NAND Chip Common Properties

maintainers:
  - Miquel Raynal <miquel.raynal@bootlin.com>

allOf:
  - $ref: nand-chip.yaml#

description: |
  The ECC strength and ECC step size properties define the user
  desires in terms of correction capability of a controller. Together,
  they request the ECC engine to correct {strength} bit errors per
  {size} bytes for a particular raw NAND chip.

  The interpretation of these parameters is implementation-defined, so
  not all implementations must support all possible
  combinations. However, implementations are encouraged to further
  specify the value(s) they support.

properties:
  $nodename:
    pattern: "^nand@[a-f0-9]$"

  reg:
    description:
      Contains the chip-select IDs.

  nand-ecc-placement:
    description:
      Location of the ECC bytes. This location is unknown by default
      but can be explicitly set to "oob", if all ECC bytes are
      known to be stored in the OOB area, or "interleaved" if ECC
      bytes will be interleaved with regular data in the main area.
    $ref: /schemas/types.yaml#/definitions/string
    enum: [ oob, interleaved ]
    deprecated: true

  nand-ecc-mode:
    description:
      Legacy ECC configuration mixing the ECC engine choice and
      configuration.
    $ref: /schemas/types.yaml#/definitions/string
    enum: [none, soft, soft_bch, hw, hw_syndrome, on-die]
    deprecated: true

  nand-bus-width:
    description:
      Bus width to the NAND chip
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [8, 16]
    default: 8

  nand-on-flash-bbt:
    description:
      With this property, the OS will search the device for a Bad
      Block Table (BBT). If not found, it will create one, reserve
      a few blocks at the end of the device to store it and update
      it as the device ages. Otherwise, the out-of-band area of a
      few pages of all the blocks will be scanned at boot time to
      find Bad Block Markers (BBM). These markers will help to
      build a volatile BBT in RAM.
    $ref: /schemas/types.yaml#/definitions/flag

  nand-ecc-maximize:
    description:
      Whether or not the ECC strength should be maximized. The
      maximum ECC strength is both controller and chip
      dependent. The ECC engine has to select the ECC config
      providing the best strength and taking the OOB area size
      constraint into account. This is particularly useful when
      only the in-band area is used by the upper layers, and you
      want to make your NAND as reliable as possible.
    $ref: /schemas/types.yaml#/definitions/flag

  nand-is-boot-medium:
    description:
      Whether or not the NAND chip is a boot medium. Drivers might
      use this information to select ECC algorithms supported by
      the boot ROM or similar restrictions.
    $ref: /schemas/types.yaml#/definitions/flag

  nand-rb:
    description:
      Contains the native Ready/Busy IDs.
    $ref: /schemas/types.yaml#/definitions/uint32-array

  rb-gpios:
    description:
      Contains one or more GPIO descriptor (the numper of descriptor
      depends on the number of R/B pins exposed by the flash) for the
      Ready/Busy pins. Active state refers to the NAND ready state and
      should be set to GPIOD_ACTIVE_HIGH unless the signal is inverted.

  wp-gpios:
    description:
      Contains one GPIO descriptor for the Write Protect pin.
      Active state refers to the NAND Write Protect state and should be
      set to GPIOD_ACTIVE_LOW unless the signal is inverted.
    maxItems: 1

required:
  - reg

# This is a generic file other binding inherit from and extend
additionalProperties: true