regmap: Lock the sync path, ensure we use the lockless _regmap_write()

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regcache-indexed.c

@@ -45,7 +45,7 @@ static int regcache_indexed_sync(struct regmap *map)
 	int ret;
 
 	for (i = 0; i < map->num_reg_defaults; i++) {
-		ret = regmap_write(map, map->reg_defaults[i].reg,
+		ret = _regmap_write(map, map->reg_defaults[i].reg,
 				    map->reg_defaults[i].def);
 		if (ret < 0)
 			return ret;

drivers/base/regmap/regcache-lzo.c

@@ -339,7 +339,7 @@ static int regcache_lzo_sync(struct regmap *map)
 		if (ret)
 			return ret;
 		map->cache_bypass = 1;
-		ret = regmap_write(map, i, val);
+		ret = _regmap_write(map, i, val);
 		map->cache_bypass = 0;
 		if (ret)
 			return ret;

drivers/base/regmap/regcache-rbtree.c

@@ -327,7 +327,7 @@ static int regcache_rbtree_sync(struct regmap *map)
 			if (val == def)
 				continue;
 			map->cache_bypass = 1;
-			ret = regmap_write(map, regtmp, val);
+			ret = _regmap_write(map, regtmp, val);
 			map->cache_bypass = 0;
 			if (ret)
 				return ret;

drivers/base/regmap/regcache.c

@@ -230,6 +230,7 @@ int regcache_sync(struct regmap *map)
 
 	BUG_ON(!map->cache_ops);
 
+	mutex_lock(&map->lock);
 	dev_dbg(map->dev, "Syncing %s cache\n",
 		map->cache_ops->name);
 	name = map->cache_ops->name;
@@ -242,7 +243,7 @@ int regcache_sync(struct regmap *map)
 			if (ret < 0)
 				goto out;
 			map->cache_bypass = 1;
-			ret = regmap_write(map, i, val);
+			ret = _regmap_write(map, i, val);
 			map->cache_bypass = 0;
 			if (ret < 0)
 				goto out;
@@ -254,6 +255,7 @@ int regcache_sync(struct regmap *map)
 	}
 out:
 	trace_regcache_sync(map->dev, name, "stop");
+	mutex_unlock(&map->lock);
 
 	return ret;
 }