regulator: core: return zero for selectors lower than linear_min_sel

Selectors lower than linear_min_sel should not be considered invalid.
Thus return zero in case _regulator_list_voltage(),
regulator_list_hardware_vsel() or regulator_list_voltage_table()
receives such selectors as argument.

Fixes: bdcd1177 ("regulator: core: validate selector against linear_min_sel")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1606325147-606-1-git-send-email-claudiu.beznea@microchip.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -2958,9 +2958,10 @@ static int _regulator_list_voltage(struct regulator_dev *rdev,
 		return rdev->desc->fixed_uV;
 
 	if (ops->list_voltage) {
-		if (selector >= rdev->desc->n_voltages ||
-		    selector < rdev->desc->linear_min_sel)
+		if (selector >= rdev->desc->n_voltages)
 			return -EINVAL;
+		if (selector < rdev->desc->linear_min_sel)
+			return 0;
 		if (lock)
 			regulator_lock(rdev);
 		ret = ops->list_voltage(rdev, selector);
@@ -3110,9 +3111,10 @@ int regulator_list_hardware_vsel(struct regulator *regulator,
 	struct regulator_dev *rdev = regulator->rdev;
 	const struct regulator_ops *ops = rdev->desc->ops;
 
-	if (selector >= rdev->desc->n_voltages ||
-	    selector < rdev->desc->linear_min_sel)
+	if (selector >= rdev->desc->n_voltages)
 		return -EINVAL;
+	if (selector < rdev->desc->linear_min_sel)
+		return 0;
 	if (ops->set_voltage_sel != regulator_set_voltage_sel_regmap)
 		return -EOPNOTSUPP;
 

drivers/regulator/helpers.c

@@ -647,9 +647,10 @@ int regulator_list_voltage_table(struct regulator_dev *rdev,
 		return -EINVAL;
 	}
 
-	if (selector >= rdev->desc->n_voltages ||
-	    selector < rdev->desc->linear_min_sel)
+	if (selector >= rdev->desc->n_voltages)
 		return -EINVAL;
+	if (selector < rdev->desc->linear_min_sel)
+		return 0;
 
 	return rdev->desc->volt_table[selector];
 }