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/max8925-regulator.c b/drivers/regulator/max8925-regulator.c
index 552cad8..8ae1475 100644
--- a/drivers/regulator/max8925-regulator.c
+++ b/drivers/regulator/max8925-regulator.c
@@ -55,7 +55,7 @@
 }
 
 static int max8925_set_voltage(struct regulator_dev *rdev,
-			       int min_uV, int max_uV)
+			       int min_uV, int max_uV, unsigned int *selector)
 {
 	struct max8925_regulator_info *info = rdev_get_drvdata(rdev);
 	unsigned char data, mask;
@@ -66,6 +66,7 @@
 		return -EINVAL;
 	}
 	data = (min_uV - info->min_uV + info->step_uV - 1) / info->step_uV;
+	*selector = data;
 	data <<= info->vol_shift;
 	mask = ((1 << info->vol_nbits) - 1) << info->vol_shift;