* manjugk@xxxxxx <manjugk@xxxxxx> [091005 23:42]:
> McSPI RX timeout issues are reported on some of the OMAP3 custom boards.
>
> After verifying configuration sequence in TRM, there seems to be issue with
> McSPI configuration sequence.
>
> The steps to be followed for both TX and RX:
> 1. Configure OMAP2_MCSPI_CHCONF0 register with required settings such as
> TX/RX mode, word length, force chip select(if required).
> 2. Set MS bit to 0 in OMAP2_MCSPI_CHCTRL0 register to provide the clock.
> 3. Enable SPI channel in OMAP2_MCSPI_MODULCTRL
>
> But, the sequence used in current code seems to be wrong. Here it is:
> 1. Set MS bit to 0 in OMAP2_MCSPI_CHCTRL0 register to provide the clock
> (This is done during bootup)
> 2. Enable SPI channel in OMAP2_MCSPI_MODULCTRL
> 3. Configure OMAP2_MCSPI_CHCONF0 register with required settings such as
> TX/RX mode, word length, force chip select(if required).
>
> After correcting configuration sequence, the timeout seems to be not
> reproducible anymore.
Please resend this to the right lists one for merging:
$ grep -A7 "SPI SUBSYSTEM" MAINTAINERS
SPI SUBSYSTEM
M: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
L: spi-devel-general@xxxxxxxxxxxxxxxxxxxxx
S: Maintained
F: Documentation/spi/
F: drivers/spi/
F: include/linux/spi/
Please also Cc linux-omap list too so people can easily keep track of it.
Regards,
Tony
>
> Signed-off-by: Manjunatha GK <manjugk@xxxxxx>
> ---
> drivers/spi/omap2_mcspi.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
> index ba1a872..846485c 100644
> --- a/drivers/spi/omap2_mcspi.c
> +++ b/drivers/spi/omap2_mcspi.c
> @@ -802,7 +802,6 @@ static void omap2_mcspi_work(struct work_struct *work)
> spi = m->spi;
> cs = spi->controller_state;
>
> - omap2_mcspi_set_enable(spi, 1);
> list_for_each_entry(t, &m->transfers, transfer_list) {
> if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
> status = -EINVAL;
> @@ -830,6 +829,9 @@ static void omap2_mcspi_work(struct work_struct *work)
> chconf |= OMAP2_MCSPI_CHCONF_TRM_TX_ONLY;
> mcspi_write_chconf0(spi, chconf);
>
> + omap2_mcspi_set_master_mode(mcspi->master);
> +
> + omap2_mcspi_set_enable(spi, 1);
> if (t->len) {
> unsigned count;
>
> --
> 1.6.0.4
>
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