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

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index ba8eff41b746104c1e96fd923f953e1622bed88c..abbc1582f457eb51bce95d8eaca748347f65e4e1 100644 (file)
--- 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;