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>

drivers/mtd/nand/nand_base.c

@@ -947,6 +947,21 @@ 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_unlock - [REPLACEABLE] unlocks specified locked blocks
  * @mtd: mtd info
@@ -1025,7 +1040,7 @@ int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	 * some operation can also clear the bit 7 of status register
 	 * eg. erase/program a locked block
 	 */
-	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+	nand_reset(chip);
 
 	/* Check, if it is write protected */
 	if (nand_check_wp(mtd)) {
@@ -1084,7 +1099,7 @@ int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	 * some operation can also clear the bit 7 of status register
 	 * eg. erase/program a locked block
 	 */
-	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+	nand_reset(chip);
 
 	/* Check, if it is write protected */
 	if (nand_check_wp(mtd)) {
@@ -2782,7 +2797,7 @@ 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)) {
@@ -3822,7 +3837,7 @@ 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);
@@ -4163,7 +4178,7 @@ 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

@@ -1100,4 +1100,8 @@ int nand_read_oob_std(struct mtd_info *mtd, struct nand_chip *chip, int page);
 /* Default read_oob syndrome implementation */
 int nand_read_oob_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
 			   int page);
+
+/* Reset and initialize a NAND device */
+int nand_reset(struct nand_chip *chip);
+
 #endif /* __LINUX_MTD_NAND_H */