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Commit f915f7aa authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
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staging:iio:ad7606: Avoid allocating buffer for each data capture 



Currently the ad7606 driver dynamically allocates and frees a transfer
buffer each time a sample capture is performed in buffered mode, which
introduces unnecessary overhead. The driver state struct already contains a
buffer that is used for transfers in one-shot mode. This buffer is large
enough to hold all samples, but not the timestamp that might be present in
buffered mode. Extend the buffer size to be able to contain the timestamp
and update the buffered capture function to use this buffer.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent e79e8027

drivers/staging/iio/adc/ad7606.h

+2 −2
Original line number Diff line number Diff line
@@ -68,9 +68,9 @@ struct ad7606_state { 
	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 * 8 * 16-bit samples + 64-bit timestamp

	 */



	unsigned short			data[8] ____cacheline_aligned;

	unsigned short			data[12] ____cacheline_aligned;

};



struct ad7606_bus_ops {

drivers/staging/iio/adc/ad7606_ring.c

+4 −10
Original line number Diff line number Diff line
@@ -46,15 +46,10 @@ static void ad7606_poll_bh_to_ring(struct work_struct *work_s) 
	struct ad7606_state *st = container_of(work_s, struct ad7606_state,

						poll_work);

	struct iio_dev *indio_dev = iio_priv_to_dev(st);

	__u8 *buf;

	int ret;



	buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);

	if (!buf)

		return;



	if (gpio_is_valid(st->pdata->gpio_frstdata)) {

		ret = st->bops->read_block(st->dev, 1, buf);

		ret = st->bops->read_block(st->dev, 1, st->data);

		if (ret)

			goto done;

		if (!gpio_get_value(st->pdata->gpio_frstdata)) {
@@ -67,22 +62,21 @@ static void ad7606_poll_bh_to_ring(struct work_struct *work_s) 
			goto done;

		}

		ret = st->bops->read_block(st->dev,

			st->chip_info->num_channels - 1, buf + 2);

			st->chip_info->num_channels - 1, st->data + 1);

		if (ret)

			goto done;

	} else {

		ret = st->bops->read_block(st->dev,

			st->chip_info->num_channels, buf);

			st->chip_info->num_channels, st->data);

		if (ret)

			goto done;

	}



	iio_push_to_buffers_with_timestamp(indio_dev, buf,

	iio_push_to_buffers_with_timestamp(indio_dev, st->data,

					   iio_get_time_ns(indio_dev));

done:

	gpio_set_value(st->pdata->gpio_convst, 0);

	iio_trigger_notify_done(indio_dev->trig);

	kfree(buf);

}



int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)