On Wed, 29 Apr 2020 10:21:29 +0300
Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
> From: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx>
>
> 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.
>
> Signed-off-by: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Fixes tag would have been nice. I've had a go by picking a patch where I
refactored this code, but I think the issue probably predates that one.
Its in 2011 so I doubt anyone will try going past that with backports ;)
Applied to the fixes-togreg branch of iio.git and marked for stable.
I'm guessing this means you have hardware and hope to get this one out
of staging shortly? *crosses fingers* :)
Jonathan
> ---
> drivers/staging/iio/resolver/ad2s1210.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
> index 4b25a3a314ed..ed404355ea4c 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.c
> +++ b/drivers/staging/iio/resolver/ad2s1210.c
> @@ -130,17 +130,24 @@ static int ad2s1210_config_write(struct ad2s1210_state *st, u8 data)
> 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;
>
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