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regmap: Don't generate gather writes for single register raw writes

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Since it is quite common for single register raw or async writes to be
generated by rbtree cache syncs or firmware downloads and essentially all
hardware will be faster with only a single transfer optimise this case by
copying single values into the internal scratch buffer before sending.

Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Mark Brown 2013-10-08 18:37:36 +01:00
parent 7e09a97940
commit 651e013e3c
1 changed files with 10 additions and 0 deletions
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10
drivers/base/regmap/regmap.c
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@ -1116,6 +1116,16 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
u8[0] |= map->write_flag_mask;
/*
* Essentially all I/O mechanisms will be faster with a single
* buffer to write. Since register syncs often generate raw
* writes of single registers optimise that case.
*/
if (val != work_val && val_len == map->format.val_bytes) {
memcpy(work_val, val, map->format.val_bytes);
val = work_val;
}
if (async && map->bus->async_write) {
struct regmap_async *async;