From: Annaliese McDermond nh6z@nh6z.net
commit 158e800e0fde91014812f5cdfb92ce812e3a33b4 upstream.
A test was added to the probe function to ensure the device was actually connected and working before successfully completing a probe. If the device was actually there, but the I2C bus was not ready yet for whatever reason, the probe fails permanently.
Change the probe so that we defer the probe on a regmap read failure so that we try the probe again when the dependent drivers are potentially loaded. This should not affect the case where the device truly isn't present because the probe will never successfully complete.
Fixes: 2aa916e67db3 ("sc16is7xx: Read the LSR register for basic device presence check") Cc: stable@vger.kernel.org Signed-off-by: Annaliese McDermond nh6z@nh6z.net Link: https://lore.kernel.org/r/010101787f9c3fd8-c1815c00-2d6b-4c85-a96a-a13e68597... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/sc16is7xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1196,7 +1196,7 @@ static int sc16is7xx_probe(struct device ret = regmap_read(regmap, SC16IS7XX_LSR_REG << SC16IS7XX_REG_SHIFT, &val); if (ret < 0) - return ret; + return -EPROBE_DEFER;
/* Alloc port structure */ s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL);