| Message ID | 20180913003920.30600-5-david@lechnology.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spi: introduce SPI_CS_WORD mode flag | expand |
Hi David, On Thu, Sep 13, 2018 at 2:40 AM David Lechner <david@lechnology.com> wrote: > This adds support for the SPI_CS_WORD flag to the TI DaVinci SPI > driver. This mode can be used as long as we are using the hardware > chip select and not a GPIO chip select. > > Signed-off-by: David Lechner <david@lechnology.com> > --- > drivers/spi/spi-davinci.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c > index d502cf504deb..8f7dcbc53c57 100644 > --- a/drivers/spi/spi-davinci.c > +++ b/drivers/spi/spi-davinci.c > @@ -230,7 +230,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) > !(spi->mode & SPI_CS_HIGH)); > } else { > if (value == BITBANG_CS_ACTIVE) { > - spidat1 |= SPIDAT1_CSHOLD_MASK; > + if (!(spi->mode & SPI_CS_WORD)) > + spidat1 |= SPIDAT1_CSHOLD_MASK; > spidat1 &= ~(0x1 << chip_sel); > } > } > @@ -440,8 +441,12 @@ static int davinci_spi_setup(struct spi_device *spi) > return retval; > } > > - if (internal_cs) > + if (internal_cs) { > set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select); > + } else if (spi->mode & SPI_CS_WORD) { > + dev_err(&spi->dev, "SPI_CS_WORD can't be use with GPIO CS\n"); > + return -EINVAL; Does the SPI core fall back to splitting the transfer in this case? > + } Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On 09/13/2018 08:44 AM, Geert Uytterhoeven wrote: > Hi David, > > On Thu, Sep 13, 2018 at 2:40 AM David Lechner <david@lechnology.com> wrote: >> This adds support for the SPI_CS_WORD flag to the TI DaVinci SPI >> driver. This mode can be used as long as we are using the hardware >> chip select and not a GPIO chip select. >> >> Signed-off-by: David Lechner <david@lechnology.com> >> --- >> drivers/spi/spi-davinci.c | 11 ++++++++--- >> 1 file changed, 8 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c >> index d502cf504deb..8f7dcbc53c57 100644 >> --- a/drivers/spi/spi-davinci.c >> +++ b/drivers/spi/spi-davinci.c >> @@ -230,7 +230,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) >> !(spi->mode & SPI_CS_HIGH)); >> } else { >> if (value == BITBANG_CS_ACTIVE) { >> - spidat1 |= SPIDAT1_CSHOLD_MASK; >> + if (!(spi->mode & SPI_CS_WORD)) >> + spidat1 |= SPIDAT1_CSHOLD_MASK; >> spidat1 &= ~(0x1 << chip_sel); >> } >> } >> @@ -440,8 +441,12 @@ static int davinci_spi_setup(struct spi_device *spi) >> return retval; >> } >> >> - if (internal_cs) >> + if (internal_cs) { >> set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select); >> + } else if (spi->mode & SPI_CS_WORD) { >> + dev_err(&spi->dev, "SPI_CS_WORD can't be use with GPIO CS\n"); >> + return -EINVAL; > > Does the SPI core fall back to splitting the transfer in this case? Hmm... it doesn't look like it. I suppose it might be best to modify the SPI core to say: if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) || gpio_is_valid(spi->cs_gpio)) { instead of: if ((spi->mode & SPI_CS_WORD) && !(ctlr->mode_bits & SPI_CS_WORD)) { Then we could drop the error above. > >> + } > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds >
On Thu, Sep 13, 2018 at 09:26:48AM -0500, David Lechner wrote: > On 09/13/2018 08:44 AM, Geert Uytterhoeven wrote: > I suppose it might be best to modify the SPI core to say: > if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) || > gpio_is_valid(spi->cs_gpio)) { > instead of: > if ((spi->mode & SPI_CS_WORD) && !(ctlr->mode_bits & SPI_CS_WORD)) { > Then we could drop the error above. Yes, that makes sense - the same thing is going to apply to any controller with this support.
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index d502cf504deb..8f7dcbc53c57 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -230,7 +230,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) !(spi->mode & SPI_CS_HIGH)); } else { if (value == BITBANG_CS_ACTIVE) { - spidat1 |= SPIDAT1_CSHOLD_MASK; + if (!(spi->mode & SPI_CS_WORD)) + spidat1 |= SPIDAT1_CSHOLD_MASK; spidat1 &= ~(0x1 << chip_sel); } } @@ -440,8 +441,12 @@ static int davinci_spi_setup(struct spi_device *spi) return retval; } - if (internal_cs) + if (internal_cs) { set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select); + } else if (spi->mode & SPI_CS_WORD) { + dev_err(&spi->dev, "SPI_CS_WORD can't be use with GPIO CS\n"); + return -EINVAL; + } } if (spi->mode & SPI_READY) @@ -976,7 +981,7 @@ static int davinci_spi_probe(struct platform_device *pdev) dspi->prescaler_limit = pdata->prescaler_limit; dspi->version = pdata->version; - dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP; + dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_WORD; if (dspi->version == SPI_VERSION_2) dspi->bitbang.flags |= SPI_READY;
This adds support for the SPI_CS_WORD flag to the TI DaVinci SPI driver. This mode can be used as long as we are using the hardware chip select and not a GPIO chip select. Signed-off-by: David Lechner <david@lechnology.com> --- drivers/spi/spi-davinci.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)