From 9ab82f071125e340a052570df90813b11574f8d4 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Wed, 9 Jan 2013 14:01:00 +0000
Subject: [PATCH] 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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
drivers/staging/iio/gyro/adis16080_core.c | 61 ++++++++++-------------
1 file changed, 25 insertions(+), 36 deletions(-)
diff --git a/drivers/staging/iio/gyro/adis16080_core.c b/drivers/staging/iio/gyro/adis16080_core.c
index 2eb559cff347..ddeae163982a 100644
--- a/drivers/staging/iio/gyro/adis16080_core.c
+++ b/drivers/staging/iio/gyro/adis16080_core.c
@@ -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;
}
- mutex_unlock(&indio_dev->mlock);
- return ret;
+ return -EINVAL;
}
static const struct iio_chan_spec adis16080_channels[] = {
--
2.20.1