regulator: core: Fix enable_count imbalance with EXCLUSIVE_GET

Since the introduction of regulator->enable_count, a driver that did
an exclusive get on an already-enabled regulator would end up with
enable_count initialized to 0 but rdev->use_count initialized to 1.
With that starting point the regulator is effectively stuck enabled,
because if the driver attempted to disable it it would fail the
enable_count underflow check in _regulator_handle_consumer_disable().

The EXCLUSIVE_GET path in _regulator_get() now initializes
enable_count along with rdev->use_count so that the regulator can be
disabled without underflowing the former.

Signed-off-by: Zev Weiss <[email protected]>
Fixes: 5451781 ("regulator: core: Only count load for enabled consumers")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: zevweiss

drivers/regulator/core.c

@@ -2133,10 +2133,13 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
 		rdev->exclusive = 1;
 
 		ret = _regulator_is_enabled(rdev);
-		if (ret > 0)
+		if (ret > 0) {
 			rdev->use_count = 1;
-		else
+			regulator->enable_count = 1;
+		} else {
 			rdev->use_count = 0;
+			regulator->enable_count = 0;
+		}
 	}
 
 	link = device_link_add(dev, &rdev->dev, DL_FLAG_STATELESS);