diff options
| author | Anatolij Gustschin <agust@denx.de> | 2013-03-13 14:57:43 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@opensource.wolfsonmicro.com> | 2013-04-01 14:30:26 +0100 |
| commit | 1ad849aee5f53353ed88d9cd3d68a51b03a7d44f (patch) | |
| tree | f76119f3243f3e778cb894b5f2dd0352fb623e91 /drivers/spi | |
| parent | b0b36b861e434ee1c1a64cb39259e262f79af62e (diff) | |
spi/mpc512x-psc: optionally keep PSC SS asserted across xfer segmensts
Some SPI slave devices require asserted chip select signal across
multiple transfer segments of an SPI message. Currently the driver
always de-asserts the internal SS signal for every single transfer
segment of the message and ignores the 'cs_change' flag of the
transfer description. Disable the internal chip select (SS) only
if this is needed and indicated by the 'cs_change' flag.
Without this change, each partial transfer of a surrounding
multi-part SPI transaction might erroneously change the SS
signal, which might prevent slaves from answering the request
that was sent in a previous transfer segment because the
transaction could be considered aborted (SS was de-asserted
before reading the response).
Reported-by: Gerhard Sittig <gerhard.sittig@ifm.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-mpc512x-psc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c index 89480b281d74..3e490ee7f275 100644 --- a/drivers/spi/spi-mpc512x-psc.c +++ b/drivers/spi/spi-mpc512x-psc.c @@ -164,7 +164,7 @@ static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi, for (i = count; i > 0; i--) { data = tx_buf ? *tx_buf++ : 0; - if (len == EOFBYTE) + if (len == EOFBYTE && t->cs_change) setbits32(&fifo->txcmd, MPC512x_PSC_FIFO_EOF); out_8(&fifo->txdata_8, data); len--; |