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staging:iio:ad799x: Preallocate sample buffer

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Avoid allocating and freeing the sample buffer for each transfer. Instead
allocate it once when we start sampling. Also pre-compute the number of bytes we
need to transfer in the same way.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-03-26 18:43:00 +00:00 committed by Jonathan Cameron
parent d00698df21
commit d8dca33027
3 changed files with 15 additions and 12 deletions
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3
drivers/staging/iio/adc/ad799x.h
View File

@ -106,6 +106,9 @@ struct ad799x_state {
u16 int_vref_mv;
unsigned id;
u16 config;
u8 *rx_buf;
unsigned int transfer_size;
};
/*

8
drivers/staging/iio/adc/ad799x_core.c
View File

@ -104,6 +104,13 @@ static int ad7997_8_update_scan_mode(struct iio_dev *indio_dev,
{
struct ad799x_state *st = iio_priv(indio_dev);
kfree(st->rx_buf);
st->rx_buf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
if (!st->rx_buf)
return -ENOMEM;
st->transfer_size = bitmap_weight(scan_mask, indio_dev->masklength) * 2;
switch (st->id) {
case ad7997:
case ad7998:
@ -665,6 +672,7 @@ static int ad799x_remove(struct i2c_client *client)
regulator_disable(st->reg);
regulator_put(st->reg);
}
kfree(st->rx_buf);
iio_device_free(indio_dev);
return 0;

16
drivers/staging/iio/adc/ad799x_ring.c
View File

@ -36,14 +36,9 @@ static irqreturn_t ad799x_trigger_handler(int irq, void *p)
struct iio_dev *indio_dev = pf->indio_dev;
struct ad799x_state *st = iio_priv(indio_dev);
s64 time_ns;
__u8 *rxbuf;
int b_sent;
u8 cmd;
rxbuf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
if (rxbuf == NULL)
goto out;
switch (st->id) {
case ad7991:
case ad7995:
@ -66,20 +61,17 @@ static irqreturn_t ad799x_trigger_handler(int irq, void *p)
}
b_sent = i2c_smbus_read_i2c_block_data(st->client,
cmd, bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength) * 2, rxbuf);
cmd, st->transfer_size, st->rx_buf);
if (b_sent < 0)
goto done;
goto out;
time_ns = iio_get_time_ns();
if (indio_dev->scan_timestamp)
memcpy(rxbuf + indio_dev->scan_bytes - sizeof(s64),
memcpy(st->rx_buf + indio_dev->scan_bytes - sizeof(s64),
&time_ns, sizeof(time_ns));
iio_push_to_buffers(indio_dev, rxbuf);
done:
kfree(rxbuf);
iio_push_to_buffers(indio_dev, st->rx_buf);
out:
iio_trigger_notify_done(indio_dev->trig);