hwmon: (ina3221) Check channel status for alarms attribute read

There is nothing critically wrong to read these two attributes
without having a is_enabled() check at this point. But reading
the MASK_ENABLE register would clear the CVRF bit according to
the datasheet. So it'd be safer to fence for disabled channels
in order to add pm runtime feature.
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/ina3221.c

@@ -200,6 +200,12 @@ static int ina3221_read_curr(struct device *dev, u32 attr,
 		return 0;
 	case hwmon_curr_crit_alarm:
 	case hwmon_curr_max_alarm:
+		/* No actual register read if channel is disabled */
+		if (!ina3221_is_enabled(ina, channel)) {
+			/* Return 0 for alert flags */
+			*val = 0;
+			return 0;
+		}
 		ret = regmap_field_read(ina->fields[reg], &regval);
 		if (ret)
 			return ret;