Commit 0b73aa63 authored Mar 29, 2014 by Mark Brown

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 <gsi@denx.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

parent 38dbfb59

drivers/spi/spi.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}