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spidev supports more communications modes

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The spidev driver doesn't currently expose all SPI communications modes to
userspace.  This passes them all through to the driver.

Two of them are potentially troublesome, in the sense that they could cause
hardware conflicts on shared busses.  It might be appropriate to add some
privilege checks for for those modes.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
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>
This commit is contained in:
Anton Vorontsov 2007-07-31 00:38:43 -07:00 committed by Linus Torvalds
parent 4ef7af5037
commit 6f166e3833
2 changed files with 14 additions and 3 deletions
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13
drivers/spi/spidev.c
View File

@ -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;

4
include/linux/spi/spidev.h
View File

@ -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
/*---------------------------------------------------------------------------*/