1. 23 Feb, 2008 1 commit
    • Ned Forrester's avatar
      spi: pxa2xx_spi clock polarity fix · b97c74bd
      Ned Forrester authored
      
      
      Fixes a sequencing bug in spi driver pxa2xx_spi.c in which the chip select
      for a transfer may be asserted before the clock polarity is set on the
      interface.  As a result of this bug, the clock signal may have the wrong
      polarity at transfer start, so it may need to make an extra half transition
      before the intended clock/data signals begin.  (This probably means all
      transfers are one bit out of sequence.)
      
      This only occurs on the first transfer following a change in clock polarity
      in systems using more than one more than one such polarity.  The fix
      assures that the clock mode is properly set before asserting chip select.
      
      This bug was introduced in a patch merged on 2006/12/10, kernel 2.6.20.
      The patch defines an additional bit in: include/asm-arm/arch-pxa/regs-ssp.h
      for 2.6.25 and newer kernels but this addition must be made in:
      include/asm-arm/arch-pxa/pxa-regs.h for kernels between 2.6.20 and 2.6.24,
      inclusive
      Signed-off-by: default avatarNed Forrester <nforrester@whoi.edu>
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b97c74bd
  2. 26 Jan, 2008 2 commits