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* spi: new spi->mode bitsDavid Brownell2009-06-301-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add two new spi_device.mode bits to accomodate more protocol options, and pass them through to usermode drivers: * SPI_NO_CS ... a second 3-wire variant, where the chipselect line is removed instead of a data line; transfers are still full duplex. This obviously has STRONG protocol implications since the chipselect transitions can't be used to synchronize state transitions with the SPI master. * SPI_READY ... defines open drain signal that's pulled low to pause the clock. This defines a 5-wire variant (normal 4-wire SPI plus READY) and two 4-wire variants (READY plus each of the 3-wire flavors). Such hardware flow control can be a big win. There are ADC converters and flash chips that expose READY signals, but not many host controllers support it today. The spi_bitbang code should be changed to use SPI_NO_CS instead of its current nonportable hack. That's a mode most hardware can easily support (unlike SPI_READY). Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: "Paulraj, Sandeep" <s-paulraj@ti.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Documentation/spi/spidev_test.c: constify some variablesWANG Cong2007-10-161-3/+3
| | | | | | | | | | Constify two char pointers and a struct in Documentation/spi/spidev_test.c. Acked-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* spidev_test utilityAnton Vorontsov2007-07-311-0/+202
This is a simple utility used to test SPI functionality. It could stand growing options to support using other test data patterns; this initial version only issues full duplex transfers, which rules out 3WIRE or Microwire links. 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>