spi: Fix handling of cs_change in core implementation

The core implementation of cs_change didn't follow the documentation
which says that cs_change in the middle of the transfer means to briefly
deassert chip select, instead it followed buggy drivers which change the
polarity of chip select.  Use a delay of 10us between deassert and
reassert simply from pulling numbers out of a hat.

Reported-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 23756b0f9036..5d826f047714 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -591,7 +591,6 @@ static int spi_transfer_one_message(struct spi_master *master,
                                     struct spi_message *msg)
 {
         struct spi_transfer *xfer;
-        bool cur_cs = true;
         bool keep_cs = false;
         int ret = 0;
 
@@ -627,8 +626,9 @@ static int spi_transfer_one_message(struct spi_master *master,
                                          &msg->transfers)) {
                                 keep_cs = true;
                         } else {
-                                cur_cs = !cur_cs;
-                                spi_set_cs(msg->spi, cur_cs);
+                                spi_set_cs(msg->spi, false);
+                                udelay(10);
+                                spi_set_cs(msg->spi, true);
                         }
                 }