SPI loopback mode definition

Loopback mode is supported by various controllers.  This mode can be
useful for testing, especially in conjunction with spidev driver.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 302b81d1d117..e180615ed25a 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -77,6 +77,7 @@ struct spi_device {
 #define SPI_CS_HIGH     0x04                    /* chipselect active high? */
 #define SPI_LSB_FIRST   0x08                    /* per-word bits-on-wire */
 #define SPI_3WIRE       0x10                    /* SI/SO signals shared */
+#define SPI_LOOP        0x20                    /* loopback mode */
         u8                      bits_per_word;
         int                     irq;
         void                    *controller_state;