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Commit 4fd432d9 authored by Bryan Wu's avatar Bryan Wu Committed by Linus Torvalds
Browse files

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: default avatarJean-Christian de Rivaz <jc@eclis.ch>
Signed-off-by: default avatarBryan Wu <bryan.wu@analog.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e26aa015

drivers/spi/spi_bfin5xx.c

+3 −15
Original line number Diff line number Diff line
@@ -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();