Re: [PATCH v2 4/4] spi: spi-davinci: Add support for SPI_CS_WORD

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 09/13/2018 08:44 AM, Geert Uytterhoeven wrote:
Hi David,

On Thu, Sep 13, 2018 at 2:40 AM David Lechner <david@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
---
  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@xxxxxxxxxxxxxx

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





[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Input]     [Linux Kernel]     [Linux SCSI]     [X.org]

  Powered by Linux