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/pcf50633-regulator.c b/drivers/regulator/pcf50633-regulator.c
index c8f41dc..69a11d9 100644
--- a/drivers/regulator/pcf50633-regulator.c
+++ b/drivers/regulator/pcf50633-regulator.c
@@ -108,7 +108,8 @@
 }
 
 static int pcf50633_regulator_set_voltage(struct regulator_dev *rdev,
-						int min_uV, int max_uV)
+					  int min_uV, int max_uV,
+					  unsigned *selector)
 {
 	struct pcf50633 *pcf;
 	int regulator_id, millivolts;
@@ -147,6 +148,8 @@
 		return -EINVAL;
 	}
 
+	*selector = volt_bits;
+
 	return pcf50633_reg_write(pcf, regnr, volt_bits);
 }