regulator: core: validate selector against linear_min_sel

There are regulators who's min selector is not zero. Selectors loops
(looping b/w zero and regulator::desc::n_voltages) might throw errors
because invalid selectors are used (lower than
regulator::desc::linear_min_sel). For this situations validate selectors
against regulator::desc::linear_min_sel.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1605280870-32432-2-git-send-email-claudiu.beznea@microchip.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -2958,7 +2958,8 @@ static int _regulator_list_voltage(struct regulator_dev *rdev,
 		return rdev->desc->fixed_uV;
 
 	if (ops->list_voltage) {
-		if (selector >= rdev->desc->n_voltages)
+		if (selector >= rdev->desc->n_voltages ||
+		    selector < rdev->desc->linear_min_sel)
 			return -EINVAL;
 		if (lock)
 			regulator_lock(rdev);
@@ -3109,7 +3110,8 @@ 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)
+	if (selector >= rdev->desc->n_voltages ||
+	    selector < rdev->desc->linear_min_sel)
 		return -EINVAL;
 	if (ops->set_voltage_sel != regulator_set_voltage_sel_regmap)
 		return -EOPNOTSUPP;
@@ -4032,6 +4034,9 @@ int regulator_set_voltage_time(struct regulator *regulator,
 
 	for (i = 0; i < rdev->desc->n_voltages; i++) {
 		/* We only look for exact voltage matches here */
+		if (i < rdev->desc->linear_min_sel)
+			continue;
+
 		voltage = regulator_list_voltage(regulator, i);
 		if (voltage < 0)
 			return -EINVAL;

drivers/regulator/helpers.c

@@ -647,7 +647,8 @@ int regulator_list_voltage_table(struct regulator_dev *rdev,
 		return -EINVAL;
 	}
 
-	if (selector >= rdev->desc->n_voltages)
+	if (selector >= rdev->desc->n_voltages ||
+	    selector < rdev->desc->linear_min_sel)
 		return -EINVAL;
 
 	return rdev->desc->volt_table[selector];