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  1. 23 9月, 2009 13 次提交
  3. 21 9月, 2009 1 次提交
  5. 19 8月, 2009 2 次提交
  7. 30 7月, 2009 2 次提交
  9. 11 7月, 2009 1 次提交
  11. 01 7月, 2009 3 次提交
    • D
      spi: bitbang bugfix in message setup · 529ba0d9
      由 David Brownell 提交于 
      Bugfix to spi_bitbang infrastructure: make sure to always set transfer
parameters on the first pass through the message's per-transfer loop.
This can matter with drivers that replace the per-word or per-buffer
transfer primitives, on busses with multiple SPI devices.

Previously, this could have started messages using the settings left after
previous messages.  The problem was observed when a high speed chip
(m25p80 type flash) was running very slowly because a low speed device
(avr8 microcontroller) had previously used the bus.  Similar faults could
have driven the low speed device too fast, or used an unexpected word
size.
Acked-by: NSteven A. Falco <sfalco@harris.com>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      529ba0d9
    • D
      spi: add spi_master flag word · 70d6027f
      由 David Brownell 提交于 
      Add a new spi_master.flags word listing constraints relevant to that
controller.  Define the first constraint bit: a half duplex restriction.
Include that constraint in the OMAP1 MicroWire controller driver.

Have the mmc_spi host be the first customer of this flag.  Its coding
relies heavily on full duplex transfers, so it must fail when the
underlying controller driver won't perform them.

(The spi_write_then_read routine could use it too: use the
temporarily-withdrawn full-duplex speedup unless this flag is set, in
which case the existing code applies.  Similarly, any spi_master
implementing only SPI_3WIRE should set the flag.)
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      70d6027f
    • D
      spi: new spi->mode bits · b55f627f
      由 David Brownell 提交于 
      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: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: "Paulraj, Sandeep" <s-paulraj@ti.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b55f627f
  13. 20 6月, 2009 8 次提交
  15. 19 6月, 2009 6 次提交
  17. 17 6月, 2009 2 次提交
  19. 13 6月, 2009 1 次提交
  21. 11 6月, 2009 1 次提交