power: supply: lego_ev3_battery: Don't ignore iio_read_channel_processed() return value

This changes the LEGO MINDSTORMS EV3 power supply driver to return an
error if iio_read_channel_processed() fails.
Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/lego_ev3_battery.c

@@ -39,7 +39,7 @@ static int lego_ev3_battery_get_property(struct power_supply *psy,
 					 union power_supply_propval *val)
 {
 	struct lego_ev3_battery *batt = power_supply_get_drvdata(psy);
-	int val2;
+	int ret, val2;
 
 	switch (psp) {
 	case POWER_SUPPLY_PROP_TECHNOLOGY:
@@ -47,11 +47,18 @@ static int lego_ev3_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 		/* battery voltage is iio channel * 2 + Vce of transistor */
-		iio_read_channel_processed(batt->iio_v, &val->intval);
+		ret = iio_read_channel_processed(batt->iio_v, &val->intval);
+		if (ret)
+			return ret;
+
 		val->intval *= 2000;
 		val->intval += 200000;
+
 		/* plus adjust for shunt resistor drop */
-		iio_read_channel_processed(batt->iio_i, &val2);
+		ret = iio_read_channel_processed(batt->iio_i, &val2);
+		if (ret)
+			return ret;
+
 		val2 *= 1000;
 		val2 /= 15;
 		val->intval += val2;
@@ -64,7 +71,10 @@ static int lego_ev3_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 		/* battery current is iio channel / 15 / 0.05 ohms */
-		iio_read_channel_processed(batt->iio_i, &val->intval);
+		ret = iio_read_channel_processed(batt->iio_i, &val->intval);
+		if (ret)
+			return ret;
+
 		val->intval *= 20000;
 		val->intval /= 15;
 		break;