On 11/15/2012 01:15 PM, Lars-Peter Clausen wrote:
> 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.
>
added to togreg branch of iio.git
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> ---
> drivers/staging/iio/adc/ad7298.h | 2 +-
> drivers/staging/iio/adc/ad7298_core.c | 1 +
> drivers/staging/iio/adc/ad7298_ring.c | 11 +++--------
> 3 files changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7298.h b/drivers/staging/iio/adc/ad7298.h
> index 18f2787..0ce9031 100644
> --- a/drivers/staging/iio/adc/ad7298.h
> +++ b/drivers/staging/iio/adc/ad7298.h
> @@ -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];
> };
>
> diff --git a/drivers/staging/iio/adc/ad7298_core.c b/drivers/staging/iio/adc/ad7298_core.c
> index 4c75114..67082ad 100644
> --- a/drivers/staging/iio/adc/ad7298_core.c
> +++ b/drivers/staging/iio/adc/ad7298_core.c
> @@ -35,6 +35,7 @@
> .sign = 'u', \
> .realbits = 12, \
> .storagebits = 16, \
> + .endianness = IIO_BE, \
> }, \
> }
>
> diff --git a/drivers/staging/iio/adc/ad7298_ring.c b/drivers/staging/iio/adc/ad7298_ring.c
> index b3dd514..e387712 100644
> --- a/drivers/staging/iio/adc/ad7298_ring.c
> +++ b/drivers/staging/iio/adc/ad7298_ring.c
> @@ -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);
>
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