| Message ID | 8aab84c51aa330cf91f4b43782a1c483e150a4e3.1671025244.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3b553e0041a65e499fa4e25ee146f01f4ec4e617 |
| Headers | show |
| Series | spi: fsl_spi: Don't change speed while chipselect is active | expand |
Hi Christophe, On Wed, 14 Dec 2022 14:41:33 +0100 Christophe Leroy <christophe.leroy@csgroup.eu> wrote: > Commit c9bfcb315104 ("spi_mpc83xx: much improved driver") made > modifications to the driver to not perform speed changes while > chipselect is active. But those changes where lost with the > convertion to tranfer_one. > > Previous implementation was allowing speed changes during > message transfer when cs_change flag was set. > At the time being, core SPI does not provide any feature to change > speed while chipselect is off, so do not allow any speed change during > message transfer, and perform the transfer setup in prepare_message > in order to set correct speed while chipselect is still off. > > Reported-by: Herve Codina <herve.codina@bootlin.com> > Fixes: 64ca1a034f00 ("spi: fsl_spi: Convert to transfer_one") > Cc: stable@vger.kernel.org > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > Tested-by: Herve Codina <herve.codina@bootlin.com> > --- > drivers/spi/spi-fsl-spi.c | 19 ++++++++++++++++--- > 1 file 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, Looks good to me. Reviewed-by: Herve Codina <herve.codina@bootlin.com> Regards, Hervé
On Wed, 14 Dec 2022 14:41:33 +0100, Christophe Leroy wrote: > Commit c9bfcb315104 ("spi_mpc83xx: much improved driver") made > modifications to the driver to not perform speed changes while > chipselect is active. But those changes where lost with the > convertion to tranfer_one. > > Previous implementation was allowing speed changes during > message transfer when cs_change flag was set. > At the time being, core SPI does not provide any feature to change > speed while chipselect is off, so do not allow any speed change during > message transfer, and perform the transfer setup in prepare_message > in order to set correct speed while chipselect is still off. > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next Thanks! [1/1] spi: fsl_spi: Don't change speed while chipselect is active commit: 3b553e0041a65e499fa4e25ee146f01f4ec4e617 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
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,
Commit c9bfcb315104 ("spi_mpc83xx: much improved driver") made modifications to the driver to not perform speed changes while chipselect is active. But those changes where lost with the convertion to tranfer_one. Previous implementation was allowing speed changes during message transfer when cs_change flag was set. At the time being, core SPI does not provide any feature to change speed while chipselect is off, so do not allow any speed change during message transfer, and perform the transfer setup in prepare_message in order to set correct speed while chipselect is still off. Reported-by: Herve Codina <herve.codina@bootlin.com> Fixes: 64ca1a034f00 ("spi: fsl_spi: Convert to transfer_one") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Herve Codina <herve.codina@bootlin.com> --- drivers/spi/spi-fsl-spi.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)