The patch titled spi: mpc52xx_psc_spi chipselect bugfix has been added to the -mm tree. Its filename is spi-mpc52xx_psc_spi-chipselect-bugfix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: spi: mpc52xx_psc_spi chipselect bugfix From: Stefano Babic <sbabic@xxxxxxx> According to the manual the "tdfOnExit" flag must be set on the last byte we want to send. The PSC controller holds SS low until the flag is set. However, the flag was set always on the last byte of the FIFO, independently if it is the last byte of the transfer. This generates spurious toggling of the SS signals that breaks the protocol of some peripherals. Fix. Signed-off-by: Stefano Babic <sbabic@xxxxxxx> Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx> Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/spi/mpc52xx_psc_spi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN drivers/spi/mpc52xx_psc_spi.c~spi-mpc52xx_psc_spi-chipselect-bugfix drivers/spi/mpc52xx_psc_spi.c --- a/drivers/spi/mpc52xx_psc_spi.c~spi-mpc52xx_psc_spi-chipselect-bugfix +++ a/drivers/spi/mpc52xx_psc_spi.c @@ -142,6 +142,7 @@ static int mpc52xx_psc_spi_transfer_rxtx unsigned rfalarm; unsigned send_at_once = MPC52xx_PSC_BUFSIZE; unsigned recv_at_once; + int last_block = 0; if (!t->tx_buf && !t->rx_buf && t->len) return -EINVAL; @@ -151,15 +152,17 @@ static int mpc52xx_psc_spi_transfer_rxtx while (rb < t->len) { if (t->len - rb > MPC52xx_PSC_BUFSIZE) { rfalarm = MPC52xx_PSC_RFALARM; + last_block = 0; } else { send_at_once = t->len - sb; rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb); + last_block = 1; } dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once); for (; send_at_once; sb++, send_at_once--) { /* set EOF flag before the last word is sent */ - if (send_at_once == 1) + if (send_at_once == 1 && last_block) out_8(&psc->ircr2, 0x01); if (tx_buf) _ Patches currently in -mm which might be from sbabic@xxxxxxx are spi-mpc52xx_psc_spi-chipselect-bugfix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html