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Commit 6f166e38 authored by Anton Vorontsov's avatar Anton Vorontsov Committed by Linus Torvalds
Browse files

spidev supports more communications modes 



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: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4ef7af50

drivers/spi/spidev.c

+10 −3
Original line number Diff line number Diff line
@@ -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;

include/linux/spi/spidev.h

+4 −0
Original line number Diff line number Diff line
@@ -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



/*---------------------------------------------------------------------------*/