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Commit 018690d3 authored by Mark Brown's avatar Mark Brown
Browse files

regmap: Allow regmap_update_bits() users to detect changes 



Some users of regmap_update_bits() would like to be able to tell their
users if they actually did an update so provide a variant which also
returns a flag indicating if an update took place. We could return a
tristate in the return value of regmap_update_bits() but this makes the
API more cumbersome to use and doesn't fit with the general zero for
success idiom we have.

Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent c86845dc

drivers/base/regmap/regmap.c

+45 −13
Original line number Diff line number Diff line
@@ -569,18 +569,9 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, 
}

EXPORT_SYMBOL_GPL(regmap_bulk_read);



/**

 * regmap_update_bits: Perform a read/modify/write cycle on the register map

 *

 * @map: Register map to update

 * @reg: Register to update

 * @mask: Bitmask to change

 * @val: New value for bitmask

 *

 * Returns zero for success, a negative number on error.

 */

int regmap_update_bits(struct regmap *map, unsigned int reg,

		       unsigned int mask, unsigned int val)

static int _regmap_update_bits(struct regmap *map, unsigned int reg,

			       unsigned int mask, unsigned int val,

			       bool *change)

{

	int ret;

	unsigned int tmp, orig;
@@ -594,16 +585,57 @@ int regmap_update_bits(struct regmap *map, unsigned int reg, 
	tmp = orig & ~mask;

	tmp |= val & mask;



	if (tmp != orig)

	if (tmp != orig) {

		ret = _regmap_write(map, reg, tmp);

		*change = true;

	} else {

		*change = false;

	}



out:

	mutex_unlock(&map->lock);



	return ret;

}



/**

 * regmap_update_bits: Perform a read/modify/write cycle on the register map

 *

 * @map: Register map to update

 * @reg: Register to update

 * @mask: Bitmask to change

 * @val: New value for bitmask

 *

 * Returns zero for success, a negative number on error.

 */

int regmap_update_bits(struct regmap *map, unsigned int reg,

		       unsigned int mask, unsigned int val)

{

	bool change;

	return _regmap_update_bits(map, reg, mask, val, &change);

}

EXPORT_SYMBOL_GPL(regmap_update_bits);



/**

 * regmap_update_bits_check: Perform a read/modify/write cycle on the

 *                           register map and report if updated

 *

 * @map: Register map to update

 * @reg: Register to update

 * @mask: Bitmask to change

 * @val: New value for bitmask

 * @change: Boolean indicating if a write was done

 *

 * Returns zero for success, a negative number on error.

 */

int regmap_update_bits_check(struct regmap *map, unsigned int reg,

			     unsigned int mask, unsigned int val,

			     bool *change)

{

	return _regmap_update_bits(map, reg, mask, val, change);

}

EXPORT_SYMBOL_GPL(regmap_update_bits_check);



static int __init regmap_initcall(void)

{

	regmap_debugfs_initcall();

include/linux/regmap.h

+3 −0
Original line number Diff line number Diff line
@@ -138,6 +138,9 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, 
		     size_t val_count);

int regmap_update_bits(struct regmap *map, unsigned int reg,

		       unsigned int mask, unsigned int val);

int regmap_update_bits_check(struct regmap *map, unsigned int reg,

			     unsigned int mask, unsigned int val,

			     bool *change);



int regcache_sync(struct regmap *map);

void regcache_cache_only(struct regmap *map, bool enable);