[PATCH] mtd: rawnand: Add status chack in r852_ready()

[Wentao Liang]

In r852_ready(), the dev get from r852_get_dev() need to be checked.
An unstable device should not be ready. A proper implementation can
be found in r852_read_byte(). Add a status check and return 0 when it is
unstable.

Fixes: 50a487e7719c ("mtd: rawnand: Pass a nand_chip object to chip->dev_ready()")
Cc: stable at vger.kernel.org # v4.20+
Signed-off-by: Wentao Liang <vulab at iscas.ac.cn>
---
 drivers/mtd/nand/raw/r852.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/nand/raw/r852.c b/drivers/mtd/nand/raw/r852.c
index b07c2f8b4035..918974d088cf 100644
--- a/drivers/mtd/nand/raw/r852.c
+++ b/drivers/mtd/nand/raw/r852.c
@@ -387,6 +387,9 @@ static int r852_wait(struct nand_chip *chip)
 static int r852_ready(struct nand_chip *chip)
 {
 	struct r852_device *dev = r852_get_dev(nand_to_mtd(chip));
+	if (dev->card_unstable)
+		return 0;
+
 	return !(r852_read_reg(dev, R852_CARD_STA) & R852_CARD_STA_BUSY);
 }
 
-- 
2.42.0.windows.2