Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-14 15:13:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

staging:iio:ad7298: Do not perform endianness conversion in buffered mode

Browse Source 
For buffered mode we do not want to perform endianness conversion in the kernel,
but rather offload it to user space, since it is not always required to do a
conversion at all. It also greatly simplifies the kernel code since no
post-processing has to be done and may allow future optimizations like streaming
data directly to a storage device or over the network via DMA.

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 2012-11-15 13:15:00 +00:00 committed by Jonathan Cameron
parent ec04cb048d
commit ca654638f2
3 changed files with 5 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/staging/iio/adc/ad7298.h
View File

@ -48,7 +48,7 @@ struct ad7298_state {
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
unsigned short rx_buf[8] ____cacheline_aligned;
unsigned short rx_buf[12] ____cacheline_aligned;
unsigned short tx_buf[2];
};

1
drivers/staging/iio/adc/ad7298_core.c
View File

@ -35,6 +35,7 @@
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
.endianness = IIO_BE, \
}, \
}

11
drivers/staging/iio/adc/ad7298_ring.c
View File

@ -76,8 +76,7 @@ static irqreturn_t ad7298_trigger_handler(int irq, void *p)
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7298_state *st = iio_priv(indio_dev);
s64 time_ns = 0;
__u16 buf[16];
int b_sent, i;
int b_sent;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
@ -85,15 +84,11 @@ static irqreturn_t ad7298_trigger_handler(int irq, void *p)
if (indio_dev->scan_timestamp) {
time_ns = iio_get_time_ns();
memcpy((u8 *)buf + indio_dev->scan_bytes - sizeof(s64),
memcpy((u8 *)st->rx_buf + indio_dev->scan_bytes - sizeof(s64),
&time_ns, sizeof(time_ns));
}
for (i = 0; i < bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength); i++)
buf[i] = be16_to_cpu(st->rx_buf[i]);
iio_push_to_buffers(indio_dev, (u8 *)buf);
iio_push_to_buffers(indio_dev, (u8 *)st->rx_buf);
done:
iio_trigger_notify_done(indio_dev->trig);