regulator: core: Try using the parent device for the default regmap

If the device doesn't have a regmap specified by the driver and we can't
find one on the device itself try its parent, providing a useful defualt
for many MFDs.

[Rewrite commit message -- broonie]

Signed-off-by: AnilKumar Ch <[email protected]>
Signed-off-by: Mark Brown <[email protected]>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ed376d9..03fad81 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3202,8 +3202,10 @@
 	rdev->desc = regulator_desc;
 	if (config->regmap)
 		rdev->regmap = config->regmap;
-	else
+	else if (dev_get_regmap(dev, NULL))
 		rdev->regmap = dev_get_regmap(dev, NULL);
+	else if (dev->parent)
+		rdev->regmap = dev_get_regmap(dev->parent, NULL);
 	INIT_LIST_HEAD(&rdev->consumer_list);
 	INIT_LIST_HEAD(&rdev->list);
 	BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier);