[PATCH] iio: humidity: hts221: fix division by zero in calibration data parsing

[Yang Zi <2959243019@qq.com>]

hts221_parse_temp_caldata() and hts221_parse_rh_caldata() compute the
sensor slope as ((cal_y1 - cal_y0) * 8000) / (cal_x1 - cal_x0). If the
device reports cal_x1 == cal_x0 the division causes a divide-by-zero
error.

Return -EINVAL when cal_x1 == cal_x0 in both functions before performing
the division.

Signed-off-by: Yang Zi <2959243019@qq.com>
---
diff --git a/drivers/iio/humidity/hts221_core.c b/drivers/iio/humidity/hts221_core.c
index bfeb0a60d3af..7d1f04951d8b 100644
--- a/drivers/iio/humidity/hts221_core.c
+++ b/drivers/iio/humidity/hts221_core.c
@@ -288,6 +288,9 @@ static int hts221_parse_temp_caldata(struct hts221_hw *hw)
         return err;
     cal_x1 = le16_to_cpu(val);
 
+    if (cal_x1 == cal_x0)
+        return -EINVAL;
+
     slope = &hw->sensors[HTS221_SENSOR_T].slope;
     b_gen = &hw->sensors[HTS221_SENSOR_T].b_gen;
 
@@ -327,6 +330,9 @@ static int hts221_parse_rh_caldata(struct hts221_hw *hw)
         return err;
     cal_x1 = le16_to_cpu(val);
 
+    if (cal_x1 == cal_x0)
+        return -EINVAL;
+
     slope = &hw->sensors[HTS221_SENSOR_H].slope;
     b_gen = &hw->sensors[HTS221_SENSOR_H].b_gen;