regulator: core: Support for continuous voltage range

Some regulators can set any voltage within the constraints range,
not being limited to specified operating points.

This patch makes it possible to describe such regulator and makes
the regulator_is_supported_voltage() function behave correctly.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/core.c

@@ -1979,6 +1979,11 @@ int regulator_is_supported_voltage(struct regulator *regulator,
 			return ret;
 	}
 
+	/* Any voltage within constrains range is fine? */
+	if (rdev->desc->continuous_voltage_range)
+		return min_uV >= rdev->constraints->min_uV &&
+				max_uV <= rdev->constraints->max_uV;
+
 	ret = regulator_count_voltages(regulator);
 	if (ret < 0)
 		return ret;

include/linux/regulator/driver.h

@@ -181,6 +181,8 @@ enum regulator_type {
  * @type: Indicates if the regulator is a voltage or current regulator.
  * @owner: Module providing the regulator, used for refcounting.
  *
+ * @continuous_voltage_range: Indicates if the regulator can set any
+ *                            voltage within constrains range.
  * @n_voltages: Number of selectors available for ops.list_voltage().
  *
  * @min_uV: Voltage given by the lowest selector (if linear mapping)
@@ -199,6 +201,7 @@ struct regulator_desc {
 	const char *name;
 	const char *supply_name;
 	int id;
+	bool continuous_voltage_range;
 	unsigned n_voltages;
 	struct regulator_ops *ops;
 	int irq;