regulator: enable supply regulator only when use count is zero

Supply regulators are disabled only when the last
reference count is removed on the child regulator
(the use count goes from 1 to 0). This patch changes
the behaviour of enable so the supply regulator is
enabled only when the use count of the child
regulator goes from 0 to 1.
Signed-off-by: Bengt Jonsson <bengt.g.jonsson@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -1267,6 +1267,7 @@ static int _regulator_enable(struct regulator_dev *rdev)
 {
 	int ret, delay;
 
+	if (rdev->use_count == 0) {
 		/* do we need to enable the supply regulator first */
 		if (rdev->supply) {
 			mutex_lock(&rdev->supply->mutex);
@@ -1278,6 +1279,7 @@ static int _regulator_enable(struct regulator_dev *rdev)
 				return ret;
 			}
 		}
+	}
 
 	/* check voltage and requested load before enabling */
 	if (rdev->constraints &&