hwmon: (gsc) add 16bit pre-scaled voltage mode

add a 16-bit pre-scaled voltage mode to adc and clarify that existing
pre-scaled mode is 24bit.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1591714640-10332-3-git-send-email-tharvey@gateworks.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/gsc-hwmon.c

@@ -159,7 +159,7 @@ gsc_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 		return -EOPNOTSUPP;
 	}
 
-	sz = (ch->mode == mode_voltage) ? 3 : 2;
+	sz = (ch->mode == mode_voltage_24bit) ? 3 : 2;
 	ret = regmap_bulk_read(hwmon->regmap, ch->reg, buf, sz);
 	if (ret)
 		return ret;
@@ -186,7 +186,8 @@ gsc_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 		/* adjust by uV offset */
 		tmp += ch->mvoffset;
 		break;
-	case mode_voltage:
+	case mode_voltage_24bit:
+	case mode_voltage_16bit:
 		/* no adjustment needed */
 		break;
 	}
@@ -336,7 +337,8 @@ static int gsc_hwmon_probe(struct platform_device *pdev)
 						     HWMON_T_LABEL;
 			i_temp++;
 			break;
-		case mode_voltage:
+		case mode_voltage_24bit:
+		case mode_voltage_16bit:
 		case mode_voltage_raw:
 			if (i_in == GSC_HWMON_MAX_IN_CH) {
 				dev_err(gsc->dev, "too many input channels\n");