Commit 9ab82f07 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

staging:iio:adis16080: Cleanup SPI transfer 



During sampling the driver currently does a spi_read followed by a spi_write.
This is not a problem per se, since CS needs to be deasserted between the two
transfers. So even if another device claims the bus between the two transfers we
should still get a result. But the code is actually spread out over multiple
functions. E.g. the spi_read happens in one function the spi_write in another,
this makes the code harder to follow. This patch re-factors the code to just use
a single spi transaction to do both the read and the write transfer.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent c21ab700

drivers/staging/iio/gyro/adis16080_core.c

+25 −36
Original line number Diff line number Diff line
@@ -42,32 +42,32 @@ struct adis16080_state { 
	u8 buf[2] ____cacheline_aligned;

};



static int adis16080_spi_write(struct iio_dev *indio_dev,

		u16 val)

static int adis16080_read_sample(struct iio_dev *indio_dev,

		u16 addr, int *val)

{

	int ret;

	struct adis16080_state *st = iio_priv(indio_dev);



	mutex_lock(&st->buf_lock);

	st->buf[0] = val >> 8;

	st->buf[1] = val;



	ret = spi_write(st->us, st->buf, 2);

	mutex_unlock(&st->buf_lock);



	return ret;

}



static int adis16080_spi_read(struct iio_dev *indio_dev,

			      u16 *val)

{

	struct spi_message m;

	int ret;

	struct adis16080_state *st = iio_priv(indio_dev);

	struct spi_transfer	t[] = {

		{

			.tx_buf		= &st->buf,

			.len		= 2,

			.cs_change	= 1,

		}, {

			.rx_buf		= &st->buf,

			.len		= 2,

		},

	};



	mutex_lock(&st->buf_lock);

	st->buf[0] = addr >> 8;

	st->buf[1] = addr;



	ret = spi_read(st->us, st->buf, 2);

	spi_message_init(&m);

	spi_message_add_tail(&t[0], &m);

	spi_message_add_tail(&t[1], &m);



	ret = spi_sync(st->us, &m);

	if (ret == 0)

		*val = sign_extend32(((st->buf[0] & 0xF) << 8) | st->buf[1], 11);

	mutex_unlock(&st->buf_lock);
@@ -81,28 +81,17 @@ static int adis16080_read_raw(struct iio_dev *indio_dev, 
			     int *val2,

			     long mask)

{

	int ret = -EINVAL;

	u16 ut = 0;

	/* Take the iio_dev status lock */

	int ret;



	mutex_lock(&indio_dev->mlock);

	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		ret = adis16080_spi_write(indio_dev,

					  chan->address |

					  ADIS16080_DIN_WRITE);

		if (ret < 0)

			break;

		ret = adis16080_spi_read(indio_dev, &ut);

		if (ret < 0)

			break;

		*val = ut;

		ret = IIO_VAL_INT;

		break;

	}

		mutex_lock(&indio_dev->mlock);

		ret = adis16080_read_sample(indio_dev, chan->address, val);

		mutex_unlock(&indio_dev->mlock);

		return ret ? ret : IIO_VAL_INT;

	}



	return ret;

	return -EINVAL;

}



static const struct iio_chan_spec adis16080_channels[] = {