Bindings/mtd/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
   7 title: Raw NAND Chip Common Properties
   8
   9 maintainers:
  10   - Miquel Raynal <miquel.raynal@bootlin.com>
  11
  12 allOf:
  13   - $ref: nand-chip.yaml#
  14
  15 description: |
  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
  26 properties:
  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
 107 required:
 108   - reg
 109
 110 # This is a generic file other binding inherit from and extend
 111 additionalProperties: true