staging: iio: ad2s1210: Fix SPI reading
commit 5e4f99a6b788047b0b8a7496c2e0c8f372f6edf2 upstream.
If the serial interface is used, the 8-bit address should be latched using
the rising edge of the WR/FSYNC signal.
This basically means that a CS change is required between the first byte
sent, and the second one.
This change splits the single-transfer transfer of 2 bytes into 2 transfers
with a single byte, and CS change in-between.
Note fixes tag is not accurate, but reflects a point beyond which there
are too many refactors to make backporting straight forward.
Fixes: b19e9ad5e2cb ("staging:iio:resolver:ad2s1210 general driver cleanup.")
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index ac13b99b..aca983f 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -114,17 +114,24 @@
static int ad2s1210_config_read(struct ad2s1210_state *st,
unsigned char address)
{
- struct spi_transfer xfer = {
- .len = 2,
- .rx_buf = st->rx,
- .tx_buf = st->tx,
+ struct spi_transfer xfers[] = {
+ {
+ .len = 1,
+ .rx_buf = &st->rx[0],
+ .tx_buf = &st->tx[0],
+ .cs_change = 1,
+ }, {
+ .len = 1,
+ .rx_buf = &st->rx[1],
+ .tx_buf = &st->tx[1],
+ },
};
int ret = 0;
ad2s1210_set_mode(MOD_CONFIG, st);
st->tx[0] = address | AD2S1210_MSB_IS_HIGH;
st->tx[1] = AD2S1210_REG_FAULT;
- ret = spi_sync_transfer(st->sdev, &xfer, 1);
+ ret = spi_sync_transfer(st->sdev, xfers, 2);
if (ret < 0)
return ret;
