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-rw-r--r--drivers/spi/spidev.c13
-rw-r--r--include/linux/spi/spidev.h4
2 files changed, 14 insertions, 3 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 38b60ad0eda0..630f781aeb19 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -55,9 +55,16 @@
static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG];
-/* Bit masks for spi_device.mode management */
-#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL)
-
+/* Bit masks for spi_device.mode management. Note that incorrect
+ * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other
+ * devices on a shared bus: CS_HIGH, because this device will be
+ * active when it shouldn't be; 3WIRE, because when active it won't
+ * behave as it should.
+ *
+ * REVISIT should changing those two modes be privileged?
+ */
+#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
+ | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP)
struct spidev_data {
struct device dev;
diff --git a/include/linux/spi/spidev.h b/include/linux/spi/spidev.h
index 7d700be57490..c93ef9d42a01 100644
--- a/include/linux/spi/spidev.h
+++ b/include/linux/spi/spidev.h
@@ -35,6 +35,10 @@
#define SPI_MODE_2 (SPI_CPOL|0)
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
+#define SPI_CS_HIGH 0x04
+#define SPI_LSB_FIRST 0x08
+#define SPI_3WIRE 0x10
+#define SPI_LOOP 0x20
/*---------------------------------------------------------------------------*/