regmap: make lock/unlock functions customizable

It is sometimes convenient for a regmap user to override the standard
regmap lock/unlock functions with custom functions.
For instance this can be useful in case an already existing spinlock
or mutex has to be used for locking a set of registers instead of the
internal regmap spinlock/mutex.
Note that the fast_io field of struct regmap_bus is ignored in case
custom locking functions are used.

Signed-off-by: Davide Ciminaghi <ciminaghi@gnudd.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 80f9ab9..b1ee824 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -31,14 +31,12 @@
 	unsigned int (*parse_val)(void *buf);
 };
 
-typedef void (*regmap_lock)(struct regmap *map);
-typedef void (*regmap_unlock)(struct regmap *map);
-
 struct regmap {
 	struct mutex mutex;
 	spinlock_t spinlock;
 	regmap_lock lock;
 	regmap_unlock unlock;
+	void *lock_arg; /* This is passed to lock/unlock functions */
 
 	struct device *dev; /* Device we do I/O on */
 	void *work_buf;     /* Scratch buffer used to format I/O */