regulator: Report actual configured voltage to set_voltage()

Change the interface used by set_voltage() to report the selected value
to the regulator core in terms of a selector used by list_voltage().
This allows the regulator core to know the voltage that was chosen
without having to do an explict get_voltage(), which would be much more
expensive as it will generally access hardware.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/isl6271a-regulator.c b/drivers/regulator/isl6271a-regulator.c
index b8cc638..b5639e8 100644
--- a/drivers/regulator/isl6271a-regulator.c
+++ b/drivers/regulator/isl6271a-regulator.c
@@ -58,7 +58,9 @@
 	return data;
 }
 
-static int isl6271a_set_voltage(struct regulator_dev *dev, int minuV, int maxuV)
+static int isl6271a_set_voltage(struct regulator_dev *dev,
+				int minuV, int maxuV,
+				unsigned *selector)
 {
 	struct isl_pmic *pmic = rdev_get_drvdata(dev);
 	int vsel, err, data;
@@ -78,6 +80,8 @@
 	/* Convert the microvolts to data for the chip */
 	data = (vsel - ISL6271A_VOLTAGE_MIN) / ISL6271A_VOLTAGE_STEP;
 
+	*selector = data;
+
 	mutex_lock(&pmic->mtx);
 
 	err = i2c_smbus_write_byte(pmic->client, data);