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spi: atmel: fix handling of cs_change set on non-last xfer 

commit fed8d8c7a6 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: 8090d6d1a4 ("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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mans Rullgard 2019-10-18 17:35:04 +02:00 committed by Greg Kroah-Hartman
parent 07039f34f1
commit 5a58c8e40d
1 changed files with 3 additions and 7 deletions
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10
drivers/spi/spi-atmel.c
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@ -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;