redonkable/alistair23-linux
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regmap: Just send the buffer directly for single register writes

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When doing a single register write we use work_buf for both the register
and the value with the buffer formatted for sending directly to the device
so we can just do a write() directly. This saves allocating a temporary
buffer if we can't do gather writes and is likely to be faster than doing
a gather write.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Mark Brown 2011-07-20 21:47:22 +01:00
parent 322a8b0340
commit 2547e201b3
1 changed files with 9 additions and 3 deletions
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12
drivers/base/regmap/regmap.c
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@ -202,13 +202,19 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
map->format.format_reg(map->work_buf, reg);
/* Try to do a gather write if we can */
if (map->bus->gather_write)
/* If we're doing a single register write we can probably just
* send the work_buf directly, otherwise try to do a gather
* write.
*/
if (val == map->work_buf + map->format.reg_bytes)
ret = map->bus->write(map->dev, map->work_buf,
map->format.reg_bytes + val_len);
else if (map->bus->gather_write)
ret = map->bus->gather_write(map->dev, map->work_buf,
map->format.reg_bytes,
val, val_len);
/* Otherwise fall back on linearising by hand. */
/* If that didn't work fall back on linearising by hand. */
if (ret == -ENOTSUPP) {
len = map->format.reg_bytes + val_len;
buf = kmalloc(len, GFP_KERNEL);