[PATCH] mtd: nand: fix interpretation of NAND_CMD_NONE in core ->cmdfunc()

[Miquel Raynal]

Some drivers (like nand_hynix.c) call ->cmdfunc() with NAND_CMD_NONE and
an address byte in order to only send one address cycle to the flash
chip.

Fix the current implementation that actually send NAND_CMD_NONE, which
is defined as -1 (cast in a u8), thus sending an 0xFF command to the
chip, which is actually a reset command.

Add the condition in both nand_command() and nand_command_lp() to avoid
calling ->cmd_ctrl() in that case.

Signed-off-by: Miquel Raynal <miquel.raynal at free-electrons.com>
---
 drivers/mtd/nand/nand_base.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index c63e4a88a653..851f25383622 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -710,7 +710,8 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
 		chip->cmd_ctrl(mtd, readcmd, ctrl);
 		ctrl &= ~NAND_CTRL_CHANGE;
 	}
-	chip->cmd_ctrl(mtd, command, ctrl);
+	if (command != NAND_CMD_NONE)
+		chip->cmd_ctrl(mtd, command, ctrl);
 
 	/* Address cycle, when necessary */
 	ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
@@ -831,7 +832,9 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
 	}
 
 	/* Command latch cycle */
-	chip->cmd_ctrl(mtd, command, NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+	if (command != NAND_CMD_NONE)
+		chip->cmd_ctrl(mtd, command,
+			       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
 
 	if (column != -1 || page_addr != -1) {
 		int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
-- 
2.11.0