From: Dragos Bogdan dragos.bogdan@analog.com
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
--- drivers/staging/iio/resolver/ad2s1210.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
--- a/drivers/staging/iio/resolver/ad2s1210.c +++ b/drivers/staging/iio/resolver/ad2s1210.c @@ -130,17 +130,24 @@ static int ad2s1210_config_write(struct 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;