regulator: Remove regulator_can_change_voltage()

There is little obvious use case for a regualtor driver to know if it is
possible to vary voltages at all by itself.  If a consumer needs to
limit what voltages it tries to set based on the system configuration
then it will need to enumerate the possible voltages, and without that
even if it is possible to change voltages that doesn't mean that
constraints or other consumers will allow whatever change the driver is
trying to do at a given time.  It doesn't even indicate if _set_voltage()
calls will work as noop _set_voltage() calls return success.

There were no users of this API that weren't abusing it and now they're
all gone so remove the API.

Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -2508,33 +2508,6 @@ int regulator_is_enabled(struct regulator *regulator)
 }
 EXPORT_SYMBOL_GPL(regulator_is_enabled);
 
-/**
- * regulator_can_change_voltage - check if regulator can change voltage
- * @regulator: regulator source
- *
- * Returns positive if the regulator driver backing the source/client
- * can change its voltage, false otherwise. Useful for detecting fixed
- * or dummy regulators and disabling voltage change logic in the client
- * driver.
- */
-int regulator_can_change_voltage(struct regulator *regulator)
-{
-	struct regulator_dev	*rdev = regulator->rdev;
-
-	if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
-		if (rdev->desc->n_voltages - rdev->desc->linear_min_sel > 1)
-			return 1;
-
-		if (rdev->desc->continuous_voltage_range &&
-		    rdev->constraints->min_uV && rdev->constraints->max_uV &&
-		    rdev->constraints->min_uV != rdev->constraints->max_uV)
-			return 1;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(regulator_can_change_voltage);
-
 /**
  * regulator_count_voltages - count regulator_list_voltage() selectors
  * @regulator: regulator source

include/linux/regulator/consumer.h

@@ -224,7 +224,6 @@ int regulator_bulk_force_disable(int num_consumers,
 void regulator_bulk_free(int num_consumers,
 			 struct regulator_bulk_data *consumers);
 
-int regulator_can_change_voltage(struct regulator *regulator);
 int regulator_count_voltages(struct regulator *regulator);
 int regulator_list_voltage(struct regulator *regulator, unsigned selector);
 int regulator_is_supported_voltage(struct regulator *regulator,
@@ -436,11 +435,6 @@ static inline void regulator_bulk_free(int num_consumers,
 {
 }
 
-static inline int regulator_can_change_voltage(struct regulator *regulator)
-{
-	return 0;
-}
-
 static inline int regulator_set_voltage(struct regulator *regulator,
 					int min_uV, int max_uV)
 {