regmap: allow to disable all locking mechanisms
We have a use case in the at24 EEPROM driver (recently converted to
using regmap instead of raw i2c/smbus calls) where we read from/write
to the regmap in a loop, while protecting the entire loop with
a mutex.
Currently this implicitly makes us use two mutexes - one in the driver
and one in regmap. While browsing the code for similar use cases I
noticed a significant number of places where locking *seems* redundant.
Allow users to completely disable any locking mechanisms in regmap
config.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 15eddc1..072a902 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -264,6 +264,9 @@ typedef void (*regmap_unlock)(void *);
* field is NULL but precious_table (see below) is not, the
* check is performed on such table (a register is precious if
* it belongs to one of the ranges specified by precious_table).
+ * @disable_locking: This regmap is either protected by external means or
+ * is guaranteed not be be accessed from multiple threads.
+ * Don't use any locking mechanisms.
* @lock: Optional lock callback (overrides regmap's default lock
* function, based on spinlock or mutex).
* @unlock: As above for unlocking.
@@ -333,6 +336,8 @@ struct regmap_config {
bool (*readable_reg)(struct device *dev, unsigned int reg);
bool (*volatile_reg)(struct device *dev, unsigned int reg);
bool (*precious_reg)(struct device *dev, unsigned int reg);
+
+ bool disable_locking;
regmap_lock lock;
regmap_unlock unlock;
void *lock_arg;