From: Mans Rullgard mans@mansr.com
[ Upstream commit fed8d8c7a6dc2a76d7764842853d81c770b0788e ]
The driver does the wrong thing when cs_change is set on a non-last xfer in a message. When cs_change is set, the driver deactivates the CS and leaves it off until a later xfer again has cs_change set whereas it should be briefly toggling CS off and on again.
This patch brings the behaviour of the driver back in line with the documentation and common sense. The delay of 10 us is the same as is used by the default spi_transfer_one_message() function in spi.c. [gregory: rebased on for-5.5 from spi tree] Fixes: 8090d6d1a415 ("spi: atmel: Refactor spi-atmel to use SPI framework queue") Signed-off-by: Mans Rullgard mans@mansr.com Acked-by: Nicolas Ferre nicolas.ferre@atmel.com Signed-off-by: Gregory CLEMENT gregory.clement@bootlin.com Link: https://lore.kernel.org/r/20191018153504.4249-1-gregory.clement@bootlin.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-atmel.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index ba8eff41b746..abbc1582f457 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -302,7 +302,6 @@ struct atmel_spi { bool use_cs_gpios;
bool keep_cs; - bool cs_active;
u32 fifo_size; }; @@ -1374,11 +1373,9 @@ static int atmel_spi_one_transfer(struct spi_master *master, &msg->transfers)) { as->keep_cs = true; } else { - as->cs_active = !as->cs_active; - if (as->cs_active) - cs_activate(as, msg->spi); - else - cs_deactivate(as, msg->spi); + cs_deactivate(as, msg->spi); + udelay(10); + cs_activate(as, msg->spi); } }
@@ -1401,7 +1398,6 @@ static int atmel_spi_transfer_one_message(struct spi_master *master, atmel_spi_lock(as); cs_activate(as, spi);
- as->cs_active = true; as->keep_cs = false;
msg->status = 0;