spi: move more spi_setup() functionality into core

Move some common spi_setup() error checks into the SPI framework from the
spi_master controller drivers:

 - Add a new "mode_bits" field to spi_master

 - Use that in spi_setup to validate the spi->mode value being
   requested.  Setting this new field is now mandatory for any
   controller supporting more than vanilla SPI_MODE_0.

 - Update all spi_master drivers to:

     * Initialize that field
     * Remove current spi_setup() checks using that value.

This is a net minor code shrink.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 9 deletions

diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
index 2d7e6b81fb4a..46b8c5c2f45e 100644
--- a/drivers/spi/xilinx_spi.c
+++ b/drivers/spi/xilinx_spi.c
@@ -158,9 +158,6 @@ static int xilinx_spi_setup_transfer(struct spi_device *spi,
         return 0;
 }
 
-/* the spi->mode bits understood by this driver: */
-#define MODEBITS (SPI_CPOL | SPI_CPHA)
-
 static int xilinx_spi_setup(struct spi_device *spi)
 {
         struct spi_bitbang *bitbang;
@@ -170,12 +167,6 @@ static int xilinx_spi_setup(struct spi_device *spi)
         xspi = spi_master_get_devdata(spi->master);
         bitbang = &xspi->bitbang;
 
-        if (spi->mode & ~MODEBITS) {
-                dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
-                        __func__, spi->mode & ~MODEBITS);
-                return -EINVAL;
-        }
-
         retval = xilinx_spi_setup_transfer(spi, NULL);
         if (retval < 0)
                 return retval;
@@ -327,6 +318,9 @@ static int __init xilinx_spi_of_probe(struct of_device *ofdev,
                 goto put_master;
         }
 
+        /* the spi->mode bits understood by this driver: */
+        master->mode_bits = SPI_CPOL | SPI_CPHA;
+
         xspi = spi_master_get_devdata(master);
         xspi->bitbang.master = spi_master_get(master);
         xspi->bitbang.chipselect = xilinx_spi_chipselect;