mtd: add read_byte support to plat_nand

Lantiq SoCs have a External Bus Unit (EBU) that is used to attach MTD media.
As we need to co-exist with PCI on the same bus, certain swapping settings must
be applied. Similar to the NOR map driver we need to apply a fix to make NAND
work. The easiest way is to use byte reads.
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/plat_nand.c

@@ -79,6 +79,7 @@ static int __devinit plat_nand_probe(struct platform_device *pdev)
 	data->chip.select_chip = pdata->ctrl.select_chip;
 	data->chip.write_buf = pdata->ctrl.write_buf;
 	data->chip.read_buf = pdata->ctrl.read_buf;
+	data->chip.read_byte = pdata->ctrl.read_byte;
 	data->chip.chip_delay = pdata->chip.chip_delay;
 	data->chip.options |= pdata->chip.options;
 	data->chip.bbt_options |= pdata->chip.bbt_options;

include/linux/mtd/nand.h

@@ -654,6 +654,7 @@ struct platform_nand_ctrl {
 	void (*cmd_ctrl)(struct mtd_info *mtd, int dat, unsigned int ctrl);
 	void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
 	void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len);
+	unsigned char (*read_byte)(struct mtd_info *mtd);
 	void *priv;
 };