[PATCH] hwmon: (pmbus/mp29502) fix potential division by zero

[Yang Zi]

The vout_bottom_div and ovp_div divider values are read back from the
device during identify and later used as divisors in several
DIV_ROUND_CLOSEST() calls. If the device reports a zero divider, these
divisions trigger a divide-by-zero error.

Validate the divider values as soon as they are read and return -EINVAL
if they are zero, so the driver fails probe instead of crashing later.

Signed-off-by: Yang Zi <2959243019@xxxxxx>
---
diff --git a/drivers/hwmon/pmbus/mp29502.c b/drivers/hwmon/pmbus/mp29502.c
index afc5e8c07e25..d606fef82b35 100644
--- a/drivers/hwmon/pmbus/mp29502.c
+++ b/drivers/hwmon/pmbus/mp29502.c
@@ -134,6 +134,8 @@ mp29502_identify_vout_divider(struct i2c_client *client, struct pmbus_driver_inf
         return ret;
 
     data->vout_bottom_div = FIELD_GET(GENMASK(11, 0), ret);
+    if (!data->vout_bottom_div)
+        return -EINVAL;
 
     ret = i2c_smbus_read_word_data(client, MFR_VOUT_PROT2);
     if (ret < 0)
@@ -160,6 +162,8 @@ mp29502_identify_ovp_divider(struct i2c_client *client, struct pmbus_driver_info
         return ret;
 
     data->ovp_div = FIELD_GET(GENMASK(9, 0), ret);
+    if (!data->ovp_div)
+        return -EINVAL;
 
     return 0;
 }