The patch titled
drivers/base/regmap/regmap.c: just send the buffer directly for single register writes
has been added to the -mm tree. Its filename is
drivers-base-regmap-regmapc-just-send-the-buffer-directly-for-single-register-writes.patch
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Subject: drivers/base/regmap/regmap.c: just send the buffer directly for single register writes
From: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/regmap/regmap.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff -puN drivers/base/regmap/regmap.c~drivers-base-regmap-regmapc-just-send-the-buffer-directly-for-single-register-writes drivers/base/regmap/regmap.c
--- a/drivers/base/regmap/regmap.c~drivers-base-regmap-regmapc-just-send-the-buffer-directly-for-single-register-writes
+++ a/drivers/base/regmap/regmap.c
@@ -202,13 +202,20 @@ static int _regmap_raw_write(struct regm
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 +
+ map->format.val_bytes);
+ 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);
_
Patches currently in -mm which might be from broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
drivers-base-regmap-regmapc-just-send-the-buffer-directly-for-single-register-writes.patch
genirq-fix-missing-parenthesises-in-generic-chip.patch
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