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  1. Jan 26, 2009
  2. Jan 06, 2009
    • David Brownell's avatar
      spi_gpio driver · d29389de
      David Brownell authored
      
      Generalize the old at91rm9200 "bootstrap" bitbanging SPI master driver as
      "spi_gpio", so it works with arbitrary GPIOs and can be configured through
      platform_data.  Such SPI masters support:
      
       - any number of bus instances (bus_num is the platform_device.id)
       - any number of chipselects (one GPIO per spi_device)
       - all four SPI_MODE values, and SPI_CS_HIGH
       - i/o word sizes from 1 to 32 bits;
       - devices configured as with any other spi_master controller
      
      When configured using platform_data, this provides relatively low clock
      rates.  On platforms that support inlined GPIO calls, significantly
      improved transfer speeds are also possible with a semi-custom driver.
      (It's still painful when accessing flash memory, but less so.)
      
      Sanity checked by using this version to replace both native controllers on
      a board with six different SPI slaves, relying on three different
      SPI_MODE_* values and both SPI_CS_HIGH settings for correct operation.
      
      [akpm@linux-foundation.org: cleanups]
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Acked-by: default avatarMagnus Damm <damm@igel.co.jp>
      Tested-by: default avatarMagnus Damm <damm@igel.co.jp>
      Cc: Torgil Svensson <torgil.svensson@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d29389de
  3. Aug 05, 2008
  4. Feb 06, 2008
  5. Jul 17, 2007
  6. May 11, 2007
  7. May 08, 2007
    • Jan Nikitenko's avatar
      au1550 SPI controller driver · 63bd2359
      Jan Nikitenko authored
      
      Here is a driver for the Alchemy au1550 PSC (Programmable Serial
      Controller) in SPI master mode.
      
      It supports dma transfers using the Alchemy descriptor based dma controller
      for 4-8 bits per word SPI transfers.  For 9-24 bits per word transfers, pio
      irq based mode is used to avoid setup of dma channels from scratch on each
      number of bits per word change.
      
      Tested with au1550; this may also work on other MIPS Alchemy cpus, like
      au1200/au1210/au1250.  Used extensively with SD card connected via SPI;
      this handles 8.1MHz SPI clock transfers using dma without any problem (the
      highest SPI clock freq possible with au1550 running on 324MHz).
      
      The driver supports sharing of SPI bus by multiple devices.  All features
      of Alchemy SPI mode are supported (all SPI modes, msb/lsb first, bits per
      word in 4-24 range).
      
      As the SPI clock of the controller depends on main input clock that shall
      be configured externally, platform data structure for au1550 SPI controller
      driver contains mainclk_hz attribute to define the input clock rate.  From
      this value, dividers of the controller for SPI clock are set up for
      required frequency.
      
      Signed-off-by: default avatarJan Nikitenko <jan.nikitenko@gmail.com>
      
      Whitespace and section fixups.  Remove partial workaround for platform
      setup bug in dma_mask setup; it couldn't work with multiple controllers.
      
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      63bd2359
    • Andrea Paterniani's avatar
      /dev/spidevB.C interface · 814a8d50
      Andrea Paterniani authored
      
      Add a filesystem API for <linux/spi/spi.h> stack.  The initial version of
      this interface is purely synchronous.
      
      dbrownell@users.sourceforge.net:
      
       Cleaned up, bugfixed; much simplified; added preliminary documentation.
      
       Works with mdev given CONFIG_SYSFS_DEPRECATED; and presumably udev.
      
       Updated SPI_IOC_MESSAGE ioctl to full spi_message semantics, supporting
       groups of one or more transfers (each of which may be full duplex if
       desired).
      
       This is marked as EXPERIMENTAL with an explicit disclaimer that the API
       (notably the ioctls) is subject to change.
      
      Signed-off-by: default avatarAndrea Paterniani <a.paterniani@swapp-eng.it>
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      814a8d50
  8. May 07, 2007
  9. Feb 14, 2007
  10. Feb 12, 2007
  11. May 21, 2006
  12. May 16, 2006
  13. Jan 14, 2006
    • David Brownell's avatar
      [PATCH] spi: misc fixes · 7111763d
      David Brownell authored
      
      This collects some small SPI patches that seem to be missing from the MM tree:
      
        - spi_butterfly kbuild hooks got dropped somehow; this restores them
        - quick fix for a (theoretical?) m25p80_write() oops noted by Andrew
        - quick fix for a potential config-specific oops for mtd_dataflash()
        - minor doc tweaks
      
      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>
      7111763d
    • David Brownell's avatar
      [PATCH] spi: add spi_bitbang driver · 9904f22a
      David Brownell authored
      
      This adds a bitbanging spi master, hooking up to board/adapter-specific glue
      code which knows how to set and read the signals (gpios etc).
      
      This code kicks in after the glue code creates a platform_device with the
      right platform_data.  That data includes I/O loops, which will usually
      come from expanding an inline function (provided in the header).  One goal
      is that the I/O loops should be easily optimized down to a few GPIO register
      accesses, in common cases, for speed and minimized overhead.
      
      This understands all the currently defined protocol tweaking options in the
      SPI framework, and might eventually serve as as reference implementation.
      
        - different word sizes (1..32 bits)
        - differing clock rates
        - SPI modes differing by CPOL (affecting chip select and I/O loops)
        - SPI modes differing by CPHA (affecting I/O loops)
        - delays (usecs) after transfers
        - temporarily deselecting chips in mid-transfer
      
      A lot of hardware could work with this framework, though common types of
      controller can't reach peak performance without switching to a driver
      structure that supports pipelining of transfers (e.g.  DMA queues) and maybe
      controllers (e.g.  IRQ driven).
      
      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>
      9904f22a
    • 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
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