3.16.82-rc1 review patch. If anyone has any objections, please let me know.
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From: Mans Rullgard mans@mansr.com
commit fed8d8c7a6dc2a76d7764842853d81c770b0788e upstream.
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 [bwhh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/spi/spi-atmel.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
--- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -242,7 +242,6 @@ struct atmel_spi { struct atmel_spi_dma dma;
bool keep_cs; - bool cs_active; };
/* Controller-specific per-slave state */ @@ -1190,11 +1189,9 @@ static int atmel_spi_one_transfer(struct &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); } }
@@ -1217,7 +1214,6 @@ static int atmel_spi_transfer_one_messag atmel_spi_lock(as); cs_activate(as, spi);
- as->cs_active = true; as->keep_cs = false;
msg->status = 0;