hwmon: (adt7470) Fix writes to temperature limit registers

commit de12d6f4 upstream.

Temperature limit registers are signed. Limits therefore need
to be clamped to (-128, 127) degrees C and not to (0, 255)
degrees C.

Without this fix, writing a limit of 128 degrees C sets the
actual limit to -128 degrees C.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
[bwh: Backported to 3.2: driver was using SENSORS_LIMIT(), which we can
 replace with clamp_val()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/hwmon/adt7470.c

@@ -515,7 +515,7 @@ static ssize_t set_temp_min(struct device *dev,
 		return -EINVAL;
 
 	temp = DIV_ROUND_CLOSEST(temp, 1000);
-	temp = SENSORS_LIMIT(temp, 0, 255);
+	temp = clamp_val(temp, -128, 127);
 
 	mutex_lock(&data->lock);
 	data->temp_min[attr->index] = temp;
@@ -549,7 +549,7 @@ static ssize_t set_temp_max(struct device *dev,
 		return -EINVAL;
 
 	temp = DIV_ROUND_CLOSEST(temp, 1000);
-	temp = SENSORS_LIMIT(temp, 0, 255);
+	temp = clamp_val(temp, -128, 127);
 
 	mutex_lock(&data->lock);
 	data->temp_max[attr->index] = temp;
@@ -826,7 +826,7 @@ static ssize_t set_pwm_tmin(struct device *dev,
 		return -EINVAL;
 
 	temp = DIV_ROUND_CLOSEST(temp, 1000);
-	temp = SENSORS_LIMIT(temp, 0, 255);
+	temp = clamp_val(temp, -128, 127);
 
 	mutex_lock(&data->lock);
 	data->pwm_tmin[attr->index] = temp;