[PATCH 3/7] regmap: Add a mutex to guard the sync operation

[Dimitris Papastamos <dp@opensource.wolfsonmicro.com>]

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
---
 drivers/base/regmap/internal.h |    1 +
 drivers/base/regmap/regcache.c |    4 ++++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 2d51b1b..a0b931d 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -32,6 +32,7 @@ struct regmap_format {
 
 struct regmap {
 	struct mutex lock;
+	struct mutex sync_lock;
 
 	struct device *dev; /* Device we do I/O on */
 	void *work_buf;     /* Scratch buffer used to format I/O */
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index f46e247..b843b5f 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -130,6 +130,8 @@ int regcache_init(struct regmap *map)
 	if (!map->max_register)
 		map->max_register = map->num_reg_defaults_raw;
 
+	mutex_init(&map->sync_lock);
+
 	if (map->cache_ops->init) {
 		dev_dbg(map->dev, "Initializing %s cache\n",
 			map->cache_ops->name);
@@ -230,6 +232,7 @@ int regcache_sync(struct regmap *map)
 
 	BUG_ON(!map->cache_ops);
 
+	mutex_lock(&map->sync_lock);
 	dev_dbg(map->dev, "Syncing %s cache\n",
 		map->cache_ops->name);
 	name = map->cache_ops->name;
@@ -254,6 +257,7 @@ int regcache_sync(struct regmap *map)
 	}
 out:
 	trace_regcache_sync(map->dev, name, "stop");
+	mutex_unlock(&map->sync_lock);
 
 	return ret;
 }
-- 
1.7.6.4