[PATCH v2] spi: Setup the master controller driver before setting the chipselect

From: Franklin S Cooper Jr
Date: Fri Oct 16 2015 - 11:29:39 EST


SPI controllers may need to be properly setup before chip selects
can be used. Therefore, wait until the spi controller has a chance
to perform their setup procedure before trying to use the chip
select.

This also insures that the chip selects pins are in a good
state before asseting them which otherwise may cause confusion.

Signed-off-by: Franklin S Cooper Jr <fcooper@xxxxxx>
---
Keystone 2 devices currently fail to boot in linux-next after the
below commit was applied:

spi: bitbang: switch to the generic implementation of transfer_one_message
commit: 0037686596832572bbca05ab168d9884d7d704c1

This patch allows Keystone 2 devices to boot again in linux-next.

Tested this patch on K2E evm and am437 starterkit which both have SPI
devices to insure regressions aren't seen.

V2 Changes:
Update commit message.

drivers/spi/spi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 4c638f3..9d5525a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2059,11 +2059,11 @@ int spi_setup(struct spi_device *spi)
if (!spi->max_speed_hz)
spi->max_speed_hz = spi->master->max_speed_hz;

- spi_set_cs(spi, false);
-
if (spi->master->setup)
status = spi->master->setup(spi);

+ spi_set_cs(spi, false);
+
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
--
2.6.1

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