spi_mpc83xx: support loopback mode

This exposes the hardware loopback mode to drivers, primarily for testing.

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, 6 insertions, 2 deletions

diff --git a/drivers/spi/spi_mpc83xx.c b/drivers/spi/spi_mpc83xx.c
index 72812bb9b40f..0c16a2b39b41 100644
--- a/drivers/spi/spi_mpc83xx.c
+++ b/drivers/spi/spi_mpc83xx.c
@@ -39,6 +39,7 @@ struct mpc83xx_spi_reg {
 };
 
 /* SPI Controller mode register definitions */
+#define SPMODE_LOOP             (1 << 30)
 #define SPMODE_CI_INACTIVEHIGH  (1 << 29)
 #define SPMODE_CP_BEGIN_EDGECLK (1 << 28)
 #define SPMODE_DIV16            (1 << 27)
@@ -155,7 +156,7 @@ static void mpc83xx_spi_chipselect(struct spi_device *spi, int value)
                 /* mask out bits we are going to set */
                 regval &= ~(SPMODE_CP_BEGIN_EDGECLK | SPMODE_CI_INACTIVEHIGH
                                 | SPMODE_LEN(0xF) | SPMODE_DIV16
-                                | SPMODE_PM(0xF) | SPMODE_REV);
+                                | SPMODE_PM(0xF) | SPMODE_REV | SPMODE_LOOP);
 
                 if (spi->mode & SPI_CPHA)
                         regval |= SPMODE_CP_BEGIN_EDGECLK;
@@ -163,6 +164,8 @@ static void mpc83xx_spi_chipselect(struct spi_device *spi, int value)
                         regval |= SPMODE_CI_INACTIVEHIGH;
                 if (!(spi->mode & SPI_LSB_FIRST))
                         regval |= SPMODE_REV;
+                if (spi->mode & SPI_LOOP)
+                        regval |= SPMODE_LOOP;
 
                 regval |= SPMODE_LEN(len);
 
@@ -273,7 +276,8 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 }
 
 /* the spi->mode bits understood by this driver: */
-#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
+#define MODEBITS        (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
+                        | SPI_LSB_FIRST | SPI_LOOP)
 
 static int mpc83xx_spi_setup(struct spi_device *spi)
 {