From c06e677aed0c86480b01faa894967daa8aa3568a Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 17 Jul 2007 04:04:03 -0700 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/hwmon/lm70.c | 4 ++++ include/linux/spi/spi.h | 1 + 2 files changed, 5 insertions(+) diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c index 7eaae3834e15..275d392eca61 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 1be5ea059477..302b81d1d117 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;