regmap: Just send the buffer directly for single register writes
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>
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index cf3565c..6aa2c4b 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -202,13 +202,19 @@
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);