1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 743c933ac4e7..c47c4b4da97e 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -250,6 +250,10 @@ struct spi_master {
         /* spi_device.mode flags understood by this controller driver */
         u16                     mode_bits;
 
+        /* other constraints relevant to this driver */
+        u16                     flags;
+#define SPI_MASTER_HALF_DUPLEX  BIT(0)          /* can't do full duplex */
+
         /* Setup mode and clock, etc (spi driver may call many times).
          *
          * IMPORTANT:  this may be called when transfers to another