[PATCH 4.14 291/323] iio: tsl2583: Fix division by a zero lux_val

From: Greg Kroah-Hartman
Date: Thu May 20 2021 - 06:54:42 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

commit af0e1871d79cfbb91f732d2c6fa7558e45c31038 upstream.

The lux_val returned from tsl2583_get_lux can potentially be zero,
so check for this to avoid a division by zero and an overflowed
gain_trim_val.

Fixes clang scan-build warning:

drivers/iio/light/tsl2583.c:345:40: warning: Either the
condition 'lux_val<0' is redundant or there is division
by zero at line 345. [zerodivcond]

Fixes: ac4f6eee8fe8 ("staging: iio: TAOS tsl258x: Device driver")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iio/light/tsl2583.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/drivers/iio/light/tsl2583.c
+++ b/drivers/iio/light/tsl2583.c
@@ -350,6 +350,14 @@ static int tsl2583_als_calibrate(struct
return lux_val;
}

+ /* Avoid division by zero of lux_value later on */
+ if (lux_val == 0) {
+ dev_err(&chip->client->dev,
+ "%s: lux_val of 0 will produce out of range trim_value\n",
+ __func__);
+ return -ENODATA;
+ }
+
gain_trim_val = (unsigned int)(((chip->als_settings.als_cal_target)
* chip->als_settings.als_gain_trim) / lux_val);
if ((gain_trim_val < 250) || (gain_trim_val > 4000)) {