hwmon: (adt7475) Potential error pointer dereferences

The adt7475_update_device() function returns error pointers.  The
problem is that in show_pwmfreq() we dereference it before the check.
And then in pwm_use_point2_pwm_at_crit_show() there isn't a check at
all.  I don't know if it's required, but it silences a static checker
warning and it's doesn't hurt anything to check.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 90837f7..1604514 100644 (file)
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -962,13 +962,14 @@ static ssize_t show_pwmfreq(struct device *dev, struct device_attribute *attr,
 {
        struct adt7475_data *data = adt7475_update_device(dev);
        struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
-       int i = clamp_val(data->range[sattr->index] & 0xf, 0,
-                         ARRAY_SIZE(pwmfreq_table) - 1);
+       int idx;
 
        if (IS_ERR(data))
                return PTR_ERR(data);
+       idx = clamp_val(data->range[sattr->index] & 0xf, 0,
+                       ARRAY_SIZE(pwmfreq_table) - 1);
 
-       return sprintf(buf, "%d\n", pwmfreq_table[i]);
+       return sprintf(buf, "%d\n", pwmfreq_table[idx]);
 }
 
 static ssize_t set_pwmfreq(struct device *dev, struct device_attribute *attr,
@@ -1004,6 +1005,10 @@ static ssize_t pwm_use_point2_pwm_at_crit_show(struct device *dev,
                                        char *buf)
 {
        struct adt7475_data *data = adt7475_update_device(dev);
+
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
        return sprintf(buf, "%d\n", !!(data->config4 & CONFIG4_MAXDUTY));
 }