regulator: Add regulator_get_exclusive() API

Some consumers require complete control of the regulator and can't
tolerate sharing it with other consumers, most commonly because they need
to have the regulator actually disabled so can't have other consumers
forcing it on. This new regulator_get_exclusive() API call allows these
consumers to explicitly request this, documenting the assumptions that
they are making.

In order to simplify coding of such consumers the use count for regulators
they request is forced to match the enabled state of the regulator when
it is requested. This is not possible for consumers which can share
regulators due to the need to keep track of the ownership of use counts.

A new API call is used rather than an additional argument to the existing
regulator_get() in order to avoid merge headaches with driver code in
other trees.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index 277f4b964df5..976b57b6912c 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -125,6 +125,8 @@ struct regulator_bulk_data {
 /* regulator get and put */
 struct regulator *__must_check regulator_get(struct device *dev,
                                              const char *id);
+struct regulator *__must_check regulator_get_exclusive(struct device *dev,
+                                                       const char *id);
 void regulator_put(struct regulator *regulator);
 
 /* regulator output control and status */
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index ce1be708ca16..73c9cd6cda7d 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -162,6 +162,8 @@ struct regulator_desc {
 struct regulator_dev {
         struct regulator_desc *desc;
         int use_count;
+        int open_count;
+        int exclusive;
 
         /* lists we belong to */
         struct list_head list; /* list of all regulators */