NAND: Reset chip on power-up

Some chips require a RESET after power-up (e.g. Micron MT29FxGxxxxx).
The first command sent is NAND_CMD_READID.
Issue a NAND_CMD_RESET in nand_scan_ident before reading the device id.
Tested with an MT29F4G08AAC.

Signed-off-by: Karl Beldan <karl.beldan@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 4069ab1278d4428928715fbb0b3bfbac498c4f40..ba05b762ed2c7b99144df648f6f2a0681796e365 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2450,6 +2450,12 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
        /* Select the device */
        chip->select_chip(mtd, 0);
 
+       /*
+        * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
+        * after power-up
+        */
+       chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+
        /* Send the command for reading device ID */
        chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
 
@@ -2620,6 +2626,8 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips)
        /* Check for a chip array */
        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);
                /* Send the command for reading device ID */
                chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
                /* Read manufacturer and device IDs */