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, 6 deletions

diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c
index 855b0b06e625..2a5abc08e857 100644
--- a/drivers/spi/spi_bitbang.c
+++ b/drivers/spi/spi_bitbang.c
@@ -188,12 +188,6 @@ int spi_bitbang_setup(struct spi_device *spi)
 
         bitbang = spi_master_get_devdata(spi->master);
 
-        /* Bitbangers can support SPI_CS_HIGH, SPI_3WIRE, and so on;
-         * add those to master->flags, and provide the other support.
-         */
-        if ((spi->mode & ~(SPI_CPOL|SPI_CPHA|bitbang->flags)) != 0)
-                return -EINVAL;
-
         if (!cs) {
                 cs = kzalloc(sizeof *cs, GFP_KERNEL);
                 if (!cs)
@@ -452,6 +446,9 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)
         spin_lock_init(&bitbang->lock);
         INIT_LIST_HEAD(&bitbang->queue);
 
+        if (!bitbang->master->mode_bits)
+                bitbang->master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
+
         if (!bitbang->master->transfer)
                 bitbang->master->transfer = spi_bitbang_transfer;
         if (!bitbang->txrx_bufs) {