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

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>

diff --git a/drivers/staging/iio/adc/ad7298.h b/drivers/staging/iio/adc/ad7298.h
index 18f27872300207b66cff69e32ba4021772209954..0ce9031bec90ef00f0eadef3aa3afa51d49f49c9 100644 (file)
--- 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 4c75114e7d7cbb6d4890acafc74f50e5a0ab17af..67082ade18508ef1ef79081ce2505175fc98ca1f 100644 (file)
--- 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 b3dd514b9627fc4f5a1c38ceea42dc3cdcde9387..e3877129222b0e2d8f715d302cf6f4077ee08d8b 100644 (file)
--- 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);