The patch titled
Blackfin SPI Driver: fix bug - spi controller driver does not assert/deassert CS correctly
has been added to the -mm tree. Its filename is
blackfin-spi-driver-fix-bug-spi-controller-driver-does-not-assert-deassert-cs-correctly.patch
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------------------------------------------------------
Subject: Blackfin SPI Driver: fix bug - spi controller driver does not assert/deassert CS correctly
From: Yi Li <yi.li@xxxxxxxxxx>
This bug can be observed when two SPI devices are sharing the spi bus: One
device is set as SPI CS 7, another one is using SPI CS 4.
In spi_bfin5xx.c: cs_active(), cs_deactive() are used to control SPI_FLG
register. From the debug bellow:
cs_active: flag: 0x7f91, chip->flag: 0x7f80, cs: 7
cs_active: flag: 0xef91, chip->flag: 0xef10, cs: 4
When device A (cs_7) activate CS 7, SPI_FLG is set as 0x7f91 (however,
SPI_FLG should be set as 0x7f80, or 0x6f91 if in broadcast mode).
Due to some HW bug (very possibly), if SPI_FLG is set as 0x7f91, SPISSEL7
is asserted, however SPISSEL4 will be asserted too (I can see this using
the scope). This is unreasonable according to HRM.
Signed-off-by: Yi Li <yi.li@xxxxxxxxxx>
Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx>
Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi_bfin5xx.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN drivers/spi/spi_bfin5xx.c~blackfin-spi-driver-fix-bug-spi-controller-driver-does-not-assert-deassert-cs-correctly drivers/spi/spi_bfin5xx.c
--- a/drivers/spi/spi_bfin5xx.c~blackfin-spi-driver-fix-bug-spi-controller-driver-does-not-assert-deassert-cs-correctly
+++ a/drivers/spi/spi_bfin5xx.c
@@ -189,6 +189,7 @@ static void cs_deactive(struct driver_da
{
u16 flag = read_FLAG(drv_data);
+ flag &= ~chip->flag;
flag |= (chip->flag << 8);
write_FLAG(drv_data, flag);
@@ -1036,7 +1037,6 @@ static int setup(struct spi_device *spi)
struct bfin5xx_spi_chip *chip_info = NULL;
struct chip_data *chip;
struct driver_data *drv_data = spi_master_get_devdata(spi->master);
- u8 spi_flg;
/* Abort device setup if requested features are not supported */
if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) {
@@ -1119,8 +1119,7 @@ static int setup(struct spi_device *spi)
* SPI_BAUD, not the real baudrate
*/
chip->baud = hz_to_spi_baud(spi->max_speed_hz);
- spi_flg = ~(1 << (spi->chip_select));
- chip->flag = ((u16) spi_flg << 8) | (1 << (spi->chip_select));
+ chip->flag = 1 << (spi->chip_select);
chip->chip_select_num = spi->chip_select;
switch (chip->bits_per_word) {
_
Patches currently in -mm which might be from yi.li@xxxxxxxxxx are
blackfin-spi-driver-fix-bug-spi-controller-driver-does-not-assert-deassert-cs-correctly.patch
blackfin-spi-driver-fix-bug-correct-usage-of-struct-spi_transfercs_change.patch
blackfin-spi-driver-make-mmc_spi-driver-work-on-blackfin.patch
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