[PATCH next] iio: adc: ad4851: Fix signedness bug in ad4851_calibrate()

[Dan Carpenter <dan.carpenter@linaro.org>]

The "c" variable is used to store error codes from ad4851_find_opt()
so it has to be signed for the error handling to work.  Change it
to type int.

Fixes: 6250803fe2ec ("iio: adc: ad4851: add ad485x driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
Btw, in ad4851_write_raw() there are some checks for negative but
the multiplication could still wrap and turn negative so we might want to
add an upper bounds as well:

    drivers/iio/adc/ad4851.c:826 ad4851_write_raw()
    warn: potential integer overflow from user 'val * st->osr'

 drivers/iio/adc/ad4851.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
index 1ad37084355e..98ebc853db79 100644
--- a/drivers/iio/adc/ad4851.c
+++ b/drivers/iio/adc/ad4851.c
@@ -492,11 +492,11 @@ static int ad4851_find_opt(const unsigned long *field, unsigned int start,
 static int ad4851_calibrate(struct iio_dev *indio_dev)
 {
 	struct ad4851_state *st = iio_priv(indio_dev);
-	unsigned int opt_delay, num_lanes, delay, i, s, c;
+	unsigned int opt_delay, num_lanes, delay, i, s;
 	enum iio_backend_interface_type interface_type;
 	DECLARE_BITMAP(pn_status, AD4851_MAX_LANES * AD4851_MAX_IODELAY);
 	bool status;
-	int ret;
+	int c, ret;
 
 	ret = iio_backend_interface_type_get(st->back, &interface_type);
 	if (ret)
-- 
2.47.2