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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: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Mark Brown 2011-11-29 20:10:36 +00:00
parent c86845dc7b
commit 018690d33e
2 changed files with 48 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
drivers/base/regmap/regmap.c
View File

@ -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();

3
include/linux/regmap.h
View File

@ -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);