[PATCH][4.9.y] iio: tsl2583: Fix division by a zero lux_val

[Colin King <colin.king@canonical.com>]

From: Colin Ian King <colin.king@canonical.com>

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@canonical.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[iwamatsu: Change file path.]
[Colin Ian King: minor context adjustments for 4.9.y]
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
---
 drivers/staging/iio/light/tsl2583.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/staging/iio/light/tsl2583.c b/drivers/staging/iio/light/tsl2583.c
index 08f1583ee34e..fb3ec56d45b6 100644
--- a/drivers/staging/iio/light/tsl2583.c
+++ b/drivers/staging/iio/light/tsl2583.c
@@ -382,6 +382,15 @@ static int taos_als_calibrate(struct iio_dev *indio_dev)
 		dev_err(&chip->client->dev, "taos_als_calibrate failed to get lux\n");
 		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->taos_settings.als_cal_target)
 			* chip->taos_settings.als_gain_trim) / lux_val);
 
-- 
2.31.1