1. 14 Jan, 2006 1 commit
    • David Brownell's avatar
      [PATCH] spi: simple SPI framework · 8ae12a0d
      David Brownell authored
      This is the core of a small SPI framework, implementing the model of a
      queue of messages which complete asynchronously (with thin synchronous
      wrappers on top).
      
        - It's still less than 2KB of ".text" (ARM).  If there's got to be a
          mid-layer for something so simple, that's the right size budget.  :)
      
        - The guts use board-specific SPI device tables to build the driver
          model tree.  (Hardware probing is rarely an option.)
      
        - This version of Kconfig includes no drivers.  At this writing there
          are two known master controller drivers (PXA/SSP, OMAP MicroWire)
          and three protocol drivers (CS8415a, ADS7846, DataFlash) with LKML
          mentions of other drivers in development.
      
        - No userspace API.  There are several implementations to compare.
          Implement them like any other driver, and bind them with sysfs.
      
      The changes from last version posted to LKML (on 11-Nov-2005) are minor,
      and include:
      
        - One bugfix (removes a FIXME), with the visible effect of making device
          names be "spiB.C" where B is the bus number and C is the chipselect.
      
        - The "caller provides DMA mappings" mechanism now has kerneldoc, for
          DMA drivers that want to be fancy.
      
        - Hey, the framework init can be subsys_init.  Even though board init
          logic fires earlier, at arch_init ... since the framework init is
          for driver support, and the board init support uses static init.
      
        - Various additional spec/doc clarifications based on discussions
          with other folk.  It adds a brief "thank you" at the end, for folk
          who've helped nudge this framework into existence.
      
      As I've said before, I think that "protocol tweaking" is the main support
      that this driver framework will need to evolve.
      
      From: Mark Underwood <basicmark@yahoo.com>
      
        Update the SPI framework to remove a potential priority inversion case by
        reverting to kmalloc if the pre-allocated DMA-safe buffer isn't available.
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      8ae12a0d
  2. 13 Jan, 2006 2 commits
  3. 12 Jan, 2006 37 commits