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staging:iio:adis16080: Cleanup SPI transfer

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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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-01-09 14:01:00 +00:00 committed by Jonathan Cameron
parent c21ab70051
commit 9ab82f0711
1 changed files with 26 additions and 37 deletions
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63
drivers/staging/iio/gyro/adis16080_core.c
View file

@ -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);
struct spi_message m;
int ret;
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] = val >> 8;
st->buf[1] = val;
st->buf[0] = addr >> 8;
st->buf[1] = addr;
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)
{
int ret;
struct adis16080_state *st = iio_priv(indio_dev);
mutex_lock(&st->buf_lock);
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;
}
mutex_unlock(&indio_dev->mlock);
return ret;
return -EINVAL;
}
static const struct iio_chan_spec adis16080_channels[] = {