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authorIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
commita1922ed661ab2c1637d0b10cde933bd9cd33d965 (patch)
tree0f1777542b385ebefd30b3586d830fd8ed6fda5b /drivers/mmc/host/mmc_spi.c
parent75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf (diff)
parentd28daf923ac5e4a0d7cecebae56f3e339189366b (diff)
Merge branch 'tracing/core' into tracing/hw-breakpoints
Conflicts: arch/Kconfig kernel/trace/trace.h Merge reason: resolve the conflicts, plus adopt to the new ring-buffer APIs. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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 240608cc7ae..a461017ce5c 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,