"cafe_ccic" is a driver for the Marvell 88ALP01 "cafe" CMOS camera
  controller.  This is the controller found in first-generation OLPC systems,
  and this driver was written with support from the OLPC project.
  
  Current status: the core driver works.  It can generate data in YUV422,
  RGB565, and RGB444 formats.  (Anybody looking at the code will see RGB32 as
  well, but that is a debugging aid which will be removed shortly).  VGA and
  QVGA modes work; CIF is there but the colors remain funky.  Only the OV7670
  sensor is known to work with this controller at this time.
  
  To try it out: either of these commands will work:
  
       mplayer tv:// -tv driver=v4l2:width=640:height=480 -nosound
       mplayer tv:// -tv driver=v4l2:width=640:height=480:outfmt=bgr16 -nosound
  
  The "xawtv" utility also works; gqcam does not, for unknown reasons.
  
  There are a few load-time options, most of which can be changed after
  loading via sysfs as well:
  
   - alloc_bufs_at_load:  Normally, the driver will not allocate any DMA
     buffers until the time comes to transfer data.  If this option is set,
     then worst-case-sized buffers will be allocated at module load time.
     This option nails down the memory for the life of the module, but
     perhaps decreases the chances of an allocation failure later on.
  
   - dma_buf_size: The size of DMA buffers to allocate.  Note that this
     option is only consulted for load-time allocation; when buffers are
     allocated at run time, they will be sized appropriately for the current
     camera settings.
  
   - n_dma_bufs: The controller can cycle through either two or three DMA
     buffers.  Normally, the driver tries to use three buffers; on faster
     systems, however, it will work well with only two.
  
   - min_buffers: The minimum number of streaming I/O buffers that the driver
     will consent to work with.  Default is one, but, on slower systems,
     better behavior with mplayer can be achieved by setting to a higher
     value (like six).
  
   - max_buffers: The maximum number of streaming I/O buffers; default is
     ten.  That number was carefully picked out of a hat and should not be
     assumed to actually mean much of anything.
  
   - flip: If this boolean parameter is set, the sensor will be instructed to
     invert the video image.  Whether it makes sense is determined by how
     your particular camera is mounted.
  
  Work is ongoing with this driver, stay tuned.
  
  jon
  
  Jonathan Corbet
  corbet@lwn.net