spidev supports more communications modes (6f166e38) · Commits · 戴 / test

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>

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

		/---------------------------------------------------------------------------/

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