Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[pandora-kernel.git] / drivers / mmc / host / mmc_spi.c

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 240608c..d55fe4f 100644 (file)
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1313,6 +1313,12 @@ static int mmc_spi_probe(struct spi_device *spi)
        struct mmc_spi_host     *host;
        int                     status;
 
+       /* We rely on full duplex transfers, mostly to reduce
+        * per-transfer overheads (by making fewer transfers).
+        */
+       if (spi->master->flags & SPI_MASTER_HALF_DUPLEX)
+               return -EINVAL;
+
        /* 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 the steady state is 0,
@@ -1556,3 +1562,4 @@ MODULE_AUTHOR("Mike Lavender, David Brownell, "
                "Hans-Peter Nilsson, Jan Nikitenko");
 MODULE_DESCRIPTION("SPI SD/MMC host driver");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:mmc_spi");