commit 0548bf4f5ad6fc3bd93c4940fa48078b34609682
author Javier Martinez Canillas <javier.martinez@collabora.co.uk> Mon Mar 02 21:40:39 2015 +0100
committer Mark Brown <broonie@kernel.org> Sun Mar 08 19:40:16 2015 +0000
tree d35bb0b948c53be97a96a776acde955e0d24363c
parent c517d838eb7d07bbe9507871fab3931deccff539

regulator: Only enable disabled regulators on resume

The _regulator_do_enable() call ought to be a no-op when called on an
already-enabled regulator.  However, as an optimization
_regulator_enable() doesn't call _regulator_do_enable() on an already
enabled regulator.  That means we never test the case of calling
_regulator_do_enable() during normal usage and there may be hidden
bugs or warnings.  We have seen warnings issued by the tps65090 driver
and bugs when using the GPIO enable pin.

Let's match the same optimization that _regulator_enable() in
regulator_suspend_finish().  That may speed up suspend/resume and also
avoids exposing hidden bugs.

[Use much clearer commit message from Doug Anderson]

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

drivers/regulator/core.c

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index b899947..0e271e5 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3807,9 +3807,11 @@
 	list_for_each_entry(rdev, &regulator_list, list) {
 		mutex_lock(&rdev->mutex);
 		if (rdev->use_count > 0  || rdev->constraints->always_on) {
-			error = _regulator_do_enable(rdev);
-			if (error)
-				ret = error;
+			if (!_regulator_is_enabled(rdev)) {
+				error = _regulator_do_enable(rdev);
+				if (error)
+					ret = error;
+			}
 		} else {
 			if (!have_full_constraints())
 				goto unlock;