regulator: Add regulator voltage range check API

Simplify checking of support for voltage ranges by providing an API which
wraps the existing count and list operations.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -1441,6 +1441,35 @@ int regulator_list_voltage(struct regulator *regulator, unsigned selector)
 }
 EXPORT_SYMBOL_GPL(regulator_list_voltage);
 
+/**
+ * regulator_is_supported_voltage - check if a voltage range can be supported
+ *
+ * @regulator: Regulator to check.
+ * @min_uV: Minimum required voltage in uV.
+ * @max_uV: Maximum required voltage in uV.
+ *
+ * Returns a boolean or a negative error code.
+ */
+int regulator_is_supported_voltage(struct regulator *regulator,
+				   int min_uV, int max_uV)
+{
+	int i, voltages, ret;
+
+	ret = regulator_count_voltages(regulator);
+	if (ret < 0)
+		return ret;
+	voltages = ret;
+
+	for (i = 0; i < voltages; i++) {
+		ret = regulator_list_voltage(regulator, i);
+
+		if (ret >= min_uV && ret <= max_uV)
+			return 1;
+	}
+
+	return 0;
+}
+
 /**
  * regulator_set_voltage - set regulator output voltage
  * @regulator: regulator source

include/linux/regulator/consumer.h

@@ -146,6 +146,8 @@ void regulator_bulk_free(int num_consumers,
 
 int regulator_count_voltages(struct regulator *regulator);
 int regulator_list_voltage(struct regulator *regulator, unsigned selector);
+int regulator_is_supported_voltage(struct regulator *regulator,
+				   int min_uV, int max_uV);
 int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV);
 int regulator_get_voltage(struct regulator *regulator);
 int regulator_set_current_limit(struct regulator *regulator,