linux-libre/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt

* Ingenic JZ4780 NAND/BCH

This file documents the device tree bindings for NAND flash devices on the
JZ4780. NAND devices are connected to the NEMC controller (described in
memory-controllers/ingenic,jz4780-nemc.txt), and thus NAND device nodes must
be children of the NEMC node.

Required NAND controller device properties:
- compatible: Should be set to "ingenic,jz4780-nand".
- reg: For each bank with a NAND chip attached, should specify a bank number,
  an offset of 0 and a size of 0x1000000 (i.e. the whole NEMC bank).

Optional NAND controller device properties:
- ingenic,bch-controller: To make use of the hardware BCH controller, this
  property must contain a phandle for the BCH controller node. The required
  properties for this node are described below. If this is not specified,
  software BCH will be used instead.

Optional children nodes:
- Individual NAND chips are children of the NAND controller node.

Required children node properties:
- reg: An integer ranging from 1 to 6 representing the CS line to use.

Optional children node properties:
- nand-ecc-step-size: ECC block size in bytes.
- nand-ecc-strength: ECC strength (max number of correctable bits).
- nand-ecc-mode: String, operation mode of the NAND ecc mode. "hw" by default
- nand-on-flash-bbt: boolean to enable on flash bbt option, if not present false
- rb-gpios: GPIO specifier for the busy pin.
- wp-gpios: GPIO specifier for the write protect pin.

Optional child node of NAND chip nodes:
- partitions: see Documentation/devicetree/bindings/mtd/partition.txt

Example:

nemc: nemc@13410000 {
	...

	nandc: nand-controller@1 {
		compatible = "ingenic,jz4780-nand";
		reg = <1 0 0x1000000>;	/* Bank 1 */

		#address-cells = <1>;
		#size-cells = <0>;

		ingenic,bch-controller = <&bch>;

		nand@1 {
			reg = <1>;

			nand-ecc-step-size = <1024>;
			nand-ecc-strength = <24>;
			nand-ecc-mode = "hw";
			nand-on-flash-bbt;

			rb-gpios = <&gpa 20 GPIO_ACTIVE_LOW>;
			wp-gpios = <&gpf 22 GPIO_ACTIVE_LOW>;

			partitions {
				#address-cells = <2>;
				#size-cells = <2>;
				...
			}
		};
	};
};

The BCH controller is a separate SoC component used for error correction on
NAND devices. The following is a description of the device properties for a
BCH controller.

Required BCH properties:
- compatible: Should be set to "ingenic,jz4780-bch".
- reg: Should specify the BCH controller registers location and length.
- clocks: Clock for the BCH controller.

Example:

bch: bch@134d0000 {
	compatible = "ingenic,jz4780-bch";
	reg = <0x134d0000 0x10000>;

	clocks = <&cgu JZ4780_CLK_BCH>;
};