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Diffstat (limited to 'drivers/mmc/host/mmc_spi.c')
| -rw-r--r-- | drivers/mmc/host/mmc_spi.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c index 240608cc7ae9..d55fe4fb7935 100644 --- 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"); |