raw-nand-chip.yaml

  1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2%YAML 1.2
  3---
  4$id: http://devicetree.org/schemas/mtd/raw-nand-chip.yaml#
  5$schema: http://devicetree.org/meta-schemas/core.yaml#
  6
  7title: Raw NAND Chip Common Properties
  8
  9maintainers:
 10  - Miquel Raynal <miquel.raynal@bootlin.com>
 11
 12allOf:
 13  - $ref: nand-chip.yaml#
 14
 15description: |
 16  The ECC strength and ECC step size properties define the user
 17  desires in terms of correction capability of a controller. Together,
 18  they request the ECC engine to correct {strength} bit errors per
 19  {size} bytes for a particular raw NAND chip.
 20
 21  The interpretation of these parameters is implementation-defined, so
 22  not all implementations must support all possible
 23  combinations. However, implementations are encouraged to further
 24  specify the value(s) they support.
 25
 26properties:
 27  $nodename:
 28    pattern: "^nand@[a-f0-9]$"
 29
 30  reg:
 31    description:
 32      Contains the chip-select IDs.
 33
 34  nand-ecc-placement:
 35    description:
 36      Location of the ECC bytes. This location is unknown by default
 37      but can be explicitly set to "oob", if all ECC bytes are
 38      known to be stored in the OOB area, or "interleaved" if ECC
 39      bytes will be interleaved with regular data in the main area.
 40    $ref: /schemas/types.yaml#/definitions/string
 41    enum: [ oob, interleaved ]
 42    deprecated: true
 43
 44  nand-ecc-mode:
 45    description:
 46      Legacy ECC configuration mixing the ECC engine choice and
 47      configuration.
 48    $ref: /schemas/types.yaml#/definitions/string
 49    enum: [none, soft, soft_bch, hw, hw_syndrome, on-die]
 50    deprecated: true
 51
 52  nand-bus-width:
 53    description:
 54      Bus width to the NAND chip
 55    $ref: /schemas/types.yaml#/definitions/uint32
 56    enum: [8, 16]
 57    default: 8
 58
 59  nand-on-flash-bbt:
 60    description:
 61      With this property, the OS will search the device for a Bad
 62      Block Table (BBT). If not found, it will create one, reserve
 63      a few blocks at the end of the device to store it and update
 64      it as the device ages. Otherwise, the out-of-band area of a
 65      few pages of all the blocks will be scanned at boot time to
 66      find Bad Block Markers (BBM). These markers will help to
 67      build a volatile BBT in RAM.
 68    $ref: /schemas/types.yaml#/definitions/flag
 69
 70  nand-ecc-maximize:
 71    description:
 72      Whether or not the ECC strength should be maximized. The
 73      maximum ECC strength is both controller and chip
 74      dependent. The ECC engine has to select the ECC config
 75      providing the best strength and taking the OOB area size
 76      constraint into account. This is particularly useful when
 77      only the in-band area is used by the upper layers, and you
 78      want to make your NAND as reliable as possible.
 79    $ref: /schemas/types.yaml#/definitions/flag
 80
 81  nand-is-boot-medium:
 82    description:
 83      Whether or not the NAND chip is a boot medium. Drivers might
 84      use this information to select ECC algorithms supported by
 85      the boot ROM or similar restrictions.
 86    $ref: /schemas/types.yaml#/definitions/flag
 87
 88  nand-rb:
 89    description:
 90      Contains the native Ready/Busy IDs.
 91    $ref: /schemas/types.yaml#/definitions/uint32-array
 92
 93  rb-gpios:
 94    description:
 95      Contains one or more GPIO descriptor (the numper of descriptor
 96      depends on the number of R/B pins exposed by the flash) for the
 97      Ready/Busy pins. Active state refers to the NAND ready state and
 98      should be set to GPIOD_ACTIVE_HIGH unless the signal is inverted.
 99
100  wp-gpios:
101    description:
102      Contains one GPIO descriptor for the Write Protect pin.
103      Active state refers to the NAND Write Protect state and should be
104      set to GPIOD_ACTIVE_LOW unless the signal is inverted.
105    maxItems: 1
106
107required:
108  - reg
109
110# This is a generic file other binding inherit from and extend
111additionalProperties: true