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authorDavid Brownell <david-b@pacbell.net>2007-07-17 04:04:03 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:23:04 -0700
commitc06e677aed0c86480b01faa894967daa8aa3568a (patch)
tree804eaf65f578d25309d546592ada439d168d19b0
parentdccd573bb02aa011a4a7146c02c409ac0bd722a0 (diff)
downloadlinux-2.6.34-ux500-c06e677aed0c86480b01faa894967daa8aa3568a.tar.gz
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>
-rw-r--r--drivers/hwmon/lm70.c4
-rw-r--r--include/linux/spi/spi.h1
2 files changed, 5 insertions, 0 deletions
diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c
index 7eaae3834e1..275d392eca6 100644
--- a/drivers/hwmon/lm70.c
+++ b/drivers/hwmon/lm70.c
@@ -96,6 +96,10 @@ static int __devinit lm70_probe(struct spi_device *spi)
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;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 1be5ea05947..302b81d1d11 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -76,6 +76,7 @@ struct spi_device {
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
#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 */
u8 bits_per_word;
int irq;
void *controller_state;