From 0b73aa63c193006c3d503d4903dd4792a26e1d50 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Sat, 29 Mar 2014 23:48:07 +0000 Subject: [PATCH] spi: Fix handling of cs_change in core implementation The core implementation of cs_change didn't follow the documentation which says that cs_change in the middle of the transfer means to briefly deassert chip select, instead it followed buggy drivers which change the polarity of chip select. Use a delay of 10us between deassert and reassert simply from pulling numbers out of a hat. Reported-by: Gerhard Sittig Signed-off-by: Mark Brown --- drivers/spi/spi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 23756b0f9036..5d826f047714 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -591,7 +591,6 @@ static int spi_transfer_one_message(struct spi_master *master, struct spi_message *msg) { struct spi_transfer *xfer; - bool cur_cs = true; bool keep_cs = false; int ret = 0; @@ -627,8 +626,9 @@ static int spi_transfer_one_message(struct spi_master *master, &msg->transfers)) { keep_cs = true; } else { - cur_cs = !cur_cs; - spi_set_cs(msg->spi, cur_cs); + spi_set_cs(msg->spi, false); + udelay(10); + spi_set_cs(msg->spi, true); } } -- 2.20.1