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* [PATCH 1/5] staging:iio:ad7298: Do not perform endianness conversion in buffered mode
@ 2012-11-15 13:15 Lars-Peter Clausen
  2012-11-15 13:15 ` [PATCH 2/5] staging:iio:ad7298: Rework regulator handling Lars-Peter Clausen
                   ` (4 more replies)
  0 siblings, 5 replies; 12+ messages in thread
From: Lars-Peter Clausen @ 2012-11-15 13:15 UTC (permalink / raw)
  To: Jonathan Cameron; +Cc: linux-iio, drivers, Lars-Peter Clausen

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>
---
 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);
-- 
1.8.0

^ permalink raw reply related	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2012-11-17 17:23 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-11-15 13:15 [PATCH 1/5] staging:iio:ad7298: Do not perform endianness conversion in buffered mode Lars-Peter Clausen
2012-11-15 13:15 ` [PATCH 2/5] staging:iio:ad7298: Rework regulator handling Lars-Peter Clausen
2012-11-17 11:17   ` Jonathan Cameron
2012-11-15 13:15 ` [PATCH 3/5] staging:iio:ad7298: Fix temperature scale and offset Lars-Peter Clausen
2012-11-17 11:19   ` Jonathan Cameron
2012-11-15 13:15 ` [PATCH 4/5] staging:iio:ad7298: Squash everything into one file Lars-Peter Clausen
2012-11-17 11:20   ` Jonathan Cameron
2012-11-17 11:34     ` Jonathan Cameron
2012-11-17 17:23       ` Lars-Peter Clausen
2012-11-15 13:15 ` [PATCH 5/5] staging:iio: Move the ad7298 driver out of staging Lars-Peter Clausen
2012-11-17 11:45   ` Jonathan Cameron
2012-11-17 11:16 ` [PATCH 1/5] staging:iio:ad7298: Do not perform endianness conversion in buffered mode Jonathan Cameron

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