mtd: nand: Create a NAND reset function

When NAND devices are resetted some initialization may have to be done,
like for example they have to be configured for the timing mode that
shall be used. To get a common place where this initialization can be
implemented create a nand_reset() function. This currently only issues
a NAND_CMD_RESET to the NAND device. The places issuing this command
manually are replaced with a call to nand_reset().

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[Linux commit: 2f94abfe35b210e7711af9202a3dcfc9e779219a]
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/mtd/nand/nand_base.c

@@ -901,6 +901,21 @@ static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
 	return status;
 }
 
+/**
+ * nand_reset - Reset and initialize a NAND device
+ * @chip: The NAND chip
+ *
+ * Returns 0 for success or negative error code otherwise
+ */
+int nand_reset(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+
+	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+
+	return 0;
+}
+
 /**
  * nand_check_erased_buf - check if a buffer contains (almost) only 0xff data
  * @buf: buffer to test
@@ -2591,7 +2606,7 @@ static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
 	 * if we don't do this. I have no clue why, but I seem to have 'fixed'
 	 * it in the doc2000 driver in August 1999.  dwmw2.
 	 */
-	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+	nand_reset(chip);
 
 	/* Check, if it is write protected */
 	if (nand_check_wp(mtd)) {
@@ -3612,7 +3627,7 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 	 * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
 	 * after power-up.
 	 */
-	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+	nand_reset(chip);
 
 	/* Send the command for reading device ID */
 	chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
@@ -3873,7 +3888,7 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
 	for (i = 1; i < maxchips; i++) {
 		chip->select_chip(mtd, i);
 		/* See comment in nand_get_flash_type for reset */
-		chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+		nand_reset(chip);
 		/* Send the command for reading device ID */
 		chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
 		/* Read manufacturer and device IDs */

include/linux/mtd/nand.h

@@ -1115,4 +1115,8 @@ int nand_check_erased_ecc_chunk(void *data, int datalen,
 				void *ecc, int ecclen,
 				void *extraoob, int extraooblen,
 				int threshold);
+
+/* Reset and initialize a NAND device */
+int nand_reset(struct nand_chip *chip);
+
 #endif /* __LINUX_MTD_NAND_H */