aboutsummaryrefslogtreecommitdiff
path: root/drivers/mmc/host/mmc_spi.c
diff options
context:
space:
mode:
authorDan Williams <[email protected]>2009-09-08 17:55:54 -0700
committerDan Williams <[email protected]>2009-09-08 17:55:54 -0700
commit9134d02bc0af4a8747d448d1f811ec5f8eb96df6 (patch)
tree704c3e5dcc10f360815c4868a74711f82fb62e27 /drivers/mmc/host/mmc_spi.c
parentbbb20089a3275a19e475dbc21320c3742e3ca423 (diff)
parent80ffb3cceaefa405f2ecd46d66500ed8d53efe74 (diff)
Merge commit 'md/for-linus' into async-tx-next
Conflicts: drivers/md/raid5.c
Diffstat (limited to 'drivers/mmc/host/mmc_spi.c')
-rw-r--r--drivers/mmc/host/mmc_spi.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 240608cc7ae9..a461017ce5ce 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,