The init function allocates memory and sets up all the board specific parameters and function pointers. When everything is set up nand_scan() is called. This function tries to detect and identify then chip. If a chip is found all the internal data fields are initialized accordingly. The structure(s) have to be zeroed out first and then filled with the necessary information about the device.

static int __init board_init (void)
{
	struct nand_chip *this;
	int err = 0;

	/* Allocate memory for MTD device structure and private data */
	this = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
	if (!this) {
		printk ("Unable to allocate NAND MTD device structure.\n");
		err = -ENOMEM;
		goto out;
	}

	board_mtd = nand_to_mtd(this);

	/* map physical address */
	baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
	if (!baseaddr) {
		printk("Ioremap to access NAND chip failed\n");
		err = -EIO;
		goto out_mtd;
	}

	/* Set address of NAND IO lines */
	this->IO_ADDR_R = baseaddr;
	this->IO_ADDR_W = baseaddr;
	/* Reference hardware control function */
	this->hwcontrol = board_hwcontrol;
	/* Set command delay time, see datasheet for correct value */
	this->chip_delay = CHIP_DEPENDEND_COMMAND_DELAY;
	/* Assign the device ready function, if available */
	this->dev_ready = board_dev_ready;
	this->eccmode = NAND_ECC_SOFT;

	/* Scan to find existence of the device */
	if (nand_scan (board_mtd, 1)) {
		err = -ENXIO;
		goto out_ior;
	}
	
	add_mtd_partitions(board_mtd, partition_info, NUM_PARTITIONS);
	goto out;

out_ior:
	iounmap(baseaddr);
out_mtd:
	kfree (this);
out:
	return err;
}
module_init(board_init);