mmc_spi: allow setting of spi mode 3

Allow the platform data structures to specify spi mode 3
(if there is a pullup on the clock line or the spi hardware
is not able to serve spi mode 0).

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 87e211df68ac..ad9e0e213f64 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1204,10 +1204,12 @@ static int mmc_spi_probe(struct spi_device *spi)
 
         /* MMC and SD specs only seem to care that sampling is on the
          * rising edge ... meaning SPI modes 0 or 3.  So either SPI mode
-         * should be legit.  We'll use mode 0 since it seems to be a
-         * bit less troublesome on some hardware ... unclear why.
+         * should be legit.  We'll use mode 0 since the steady state is 0,
+         * which is appropriate for hotplugging, unless the platform data
+         * specify mode 3 (if hardware is not compatible to mode 0).
          */
-        spi->mode = SPI_MODE_0;
+        if (spi->mode != SPI_MODE_3)
+                spi->mode = SPI_MODE_0;
         spi->bits_per_word = 8;
 
         status = spi_setup(spi);