SPI: add 3wire mode flag
Add a new spi->mode bit: SPI_3WIRE, for chips where the SI and SO signals
are shared (and which are thus only half duplex). Update the LM70 driver
to require support for that hardware mode from the controller.
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>
diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c
index 7eaae38..275d392 100644
--- a/drivers/hwmon/lm70.c
+++ b/drivers/hwmon/lm70.c
@@ -96,6 +96,10 @@
struct lm70 *p_lm70;
int status;
+ /* signaling is SPI_MODE_0 on a 3-wire link (shared SI/SO) */
+ if ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE))
+ return -EINVAL;
+
p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
if (!p_lm70)
return -ENOMEM;