diff options
Diffstat (limited to 'drivers/spi/spi-fsl-spi.c')
| -rw-r--r-- | drivers/spi/spi-fsl-spi.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c index 731624f157fc..93152144fd2e 100644 --- a/drivers/spi/spi-fsl-spi.c +++ b/drivers/spi/spi-fsl-spi.c @@ -333,13 +333,26 @@ static int fsl_spi_prepare_message(struct spi_controller *ctlr, { struct mpc8xxx_spi *mpc8xxx_spi = spi_controller_get_devdata(ctlr); struct spi_transfer *t; + struct spi_transfer *first; + + first = list_first_entry(&m->transfers, struct spi_transfer, + transfer_list); /* * In CPU mode, optimize large byte transfers to use larger * bits_per_word values to reduce number of interrupts taken. + * + * Some glitches can appear on the SPI clock when the mode changes. + * Check that there is no speed change during the transfer and set it up + * now to change the mode without having a chip-select asserted. */ - if (!(mpc8xxx_spi->flags & SPI_CPM_MODE)) { - list_for_each_entry(t, &m->transfers, transfer_list) { + list_for_each_entry(t, &m->transfers, transfer_list) { + if (t->speed_hz != first->speed_hz) { + dev_err(&m->spi->dev, + "speed_hz cannot change during message.\n"); + return -EINVAL; + } + if (!(mpc8xxx_spi->flags & SPI_CPM_MODE)) { if (t->len < 256 || t->bits_per_word != 8) continue; if ((t->len & 3) == 0) @@ -348,7 +361,7 @@ static int fsl_spi_prepare_message(struct spi_controller *ctlr, t->bits_per_word = 16; } } - return 0; + return fsl_spi_setup_transfer(m->spi, first); } static int fsl_spi_transfer_one(struct spi_controller *controller, |