Messages in this thread Patch in this message | | | From | Mark Brown <> | Subject | [PATCH] regmap: Allow regmap_update_bits() users to detect changes | Date | Tue, 29 Nov 2011 20:11:46 +0000 |
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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> --- drivers/base/regmap/regmap.c | 58 ++++++++++++++++++++++++++++++++--------- include/linux/regmap.h | 3 ++ 2 files changed, 48 insertions(+), 13 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index a862090..add5da6 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -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(); diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 81dfe0a..a83e4a0 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -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); -- 1.7.7.3
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