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authorAnton Vorontsov <avorontsov@ru.mvista.com>2007-07-31 03:38:43 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-31 18:39:40 -0400
commit6f166e3833d953f0acf77eb7d426840da9e1a87f (patch)
tree95a15d4662f41b7a6b86c05d2558de16a86bc27e /drivers/spi
parent4ef7af50373778ee248a2493c9cf62a2299806a8 (diff)
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: 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>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spidev.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 38b60ad0eda0..630f781aeb19 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -55,9 +55,16 @@
55static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; 55static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG];
56 56
57 57
58/* Bit masks for spi_device.mode management */ 58/* Bit masks for spi_device.mode management. Note that incorrect
59#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL) 59 * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other
60 60 * devices on a shared bus: CS_HIGH, because this device will be
61 * active when it shouldn't be; 3WIRE, because when active it won't
62 * behave as it should.
63 *
64 * REVISIT should changing those two modes be privileged?
65 */
66#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
67 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP)
61 68
62struct spidev_data { 69struct spidev_data {
63 struct device dev; 70 struct device dev;