linux/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
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   1GPIO assisted NAND flash
   2
   3The GPIO assisted NAND flash uses a memory mapped interface to
   4read/write the NAND commands and data and GPIO pins for the control
   5signals.
   6
   7Required properties:
   8- compatible : "gpio-control-nand"
   9- reg : should specify localbus chip select and size used for the chip.  The
  10  resource describes the data bus connected to the NAND flash and all accesses
  11  are made in native endianness.
  12- #address-cells, #size-cells : Must be present if the device has sub-nodes
  13  representing partitions.
  14- gpios : specifies the gpio pins to control the NAND device.  nwp is an
  15  optional gpio and may be set to 0 if not present.
  16
  17Optional properties:
  18- bank-width : Width (in bytes) of the device.  If not present, the width
  19  defaults to 1 byte.
  20- chip-delay : chip dependent delay for transferring data from array to
  21  read registers (tR).  If not present then a default of 20us is used.
  22- gpio-control-nand,io-sync-reg : A 64-bit physical address for a read
  23  location used to guard against bus reordering with regards to accesses to
  24  the GPIO's and the NAND flash data bus.  If present, then after changing
  25  GPIO state and before and after command byte writes, this register will be
  26  read to ensure that the GPIO accesses have completed.
  27
  28The device tree may optionally contain sub-nodes describing partitions of the
  29address space. See partition.txt for more detail.
  30
  31Examples:
  32
  33gpio-nand@1,0 {
  34        compatible = "gpio-control-nand";
  35        reg = <1 0x0000 0x2>;
  36        #address-cells = <1>;
  37        #size-cells = <1>;
  38        gpios = <&banka 1 0     /* rdy */
  39                 &banka 2 0     /* nce */
  40                 &banka 3 0     /* ale */
  41                 &banka 4 0     /* cle */
  42                 0              /* nwp */>;
  43
  44        partition@0 {
  45        ...
  46        };
  47};
  48