spi_bfin: wait for tx to complete on full duplex paths

Full duplex SPI operation should not read a dummy byte at the first transfer.
Bug and fix by Jean-Christian de Rivaz <jc@eclis.ch>:

http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3678

Signed-off-by: Jean-Christian de Rivaz <jc@eclis.ch>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
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, 15 deletions

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index ce4692cdb3b2..f61b5eeb0427 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -358,14 +358,10 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
 
 static void u8_duplex(struct driver_data *drv_data)
 {
-        /* poll for SPI completion before start */
-        while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
-                cpu_relax();
-
         /* in duplex mode, clk is triggered by writing of TDBR */
         while (drv_data->rx < drv_data->rx_end) {
                 write_TDBR(drv_data, (*(u8 *) (drv_data->tx)));
-                while (read_STAT(drv_data) & BIT_STAT_TXS)
+                while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
                         cpu_relax();
                 while (!(read_STAT(drv_data) & BIT_STAT_RXS))
                         cpu_relax();
@@ -495,14 +491,10 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
 
 static void u16_duplex(struct driver_data *drv_data)
 {
-        /* poll for SPI completion before start */
-        while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
-                cpu_relax();
-
         /* in duplex mode, clk is triggered by writing of TDBR */
         while (drv_data->tx < drv_data->tx_end) {
                 write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
-                while (read_STAT(drv_data) & BIT_STAT_TXS)
+                while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
                         cpu_relax();
                 while (!(read_STAT(drv_data) & BIT_STAT_RXS))
                         cpu_relax();
@@ -516,15 +508,11 @@ static void u16_cs_chg_duplex(struct driver_data *drv_data)
 {
         struct chip_data *chip = drv_data->cur_chip;
 
-        /* poll for SPI completion before start */
-        while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
-                cpu_relax();
-
         while (drv_data->tx < drv_data->tx_end) {
                 cs_active(drv_data, chip);
 
                 write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
-                while (read_STAT(drv_data) & BIT_STAT_TXS)
+                while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
                         cpu_relax();
                 while (!(read_STAT(drv_data) & BIT_STAT_RXS))
                         cpu_relax();