+/* 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)