				  ==============================
				  FUJITSU MB93493 COMPANION CHIP
				  ==============================

				 ================================
				 VISUAL DISPLAY CONTROLLER DRIVER
				 ================================


The MB93493 VDC is a piece of hardware that turns the data it is given into a video signal on its
output in one of a number of formats. The VDC has no display memory of its own, and has to be fed
everything in 32 byte chunks by the CPU (the CPU has DMA controllers available). This means that
the kernel has to set aside a contiguous piece of memory for use as an image buffer.


====================
COMMAND LINE OPTIONS
====================

The VDC driver takes a kernel command line option to give it two pieces of information: how much
memory it should allocate, and the default image parameters it should assume.

The option takes one of the following forms:

 (*) vdc=nnnK
 (*) vdc=nnnM

     Allocate a buffer of the specified amount of memory, using the default image format.

 (*) vdc=AAAxBBB[suboptions]

     Allocate a buffer big enough to hold at least one image of the size AAAxBBB.

 (*) vdc=pal[suboptions]
 (*) vdc=ntsc[suboptions]

     Allocate a buffer big enough to hold a PAL or NTSC television image. The basic image
     parameters are defaulted to be appropriate to the desired image format.

 (*) vdc=vga[suboptions]

     Allocates a buffer big enough to hold an 640x480 RGB image.

 (*) vdc=lcd[suboptions]

     This option is only available on the MB93093 PDK, and it allocates a buffer big enough to
     hold an RGB image for display on the PDK's LCD display.


Suboptions can be given to some of the main option strings to further configure the display
parameters and the number of images slots to be allocated:

 (*) [...]-16
 (*) [...]-24
 (*) [...]-32

     This suboption, if present, specifies the number of bits to allocate per pixel.

 (*) [...]*<n>

     This suboption, if present, specifies the number of image slots to allocate.

 (*) [...]:isb

     This suboption, if present, specifies that the bottom field of an interlaced frame should
     be skipped when displaying. No space will be allocated in the buffer for the missing field.


============
DEVICE FILES
============

The driver supports two miscellaneous character device files:

 (*) /dev/fr400cc_vdc [major 10, minor 244]

     This device file is the main display driver interface. It can be mmapped to gain access to
     the image buffer, and it can be polled and read to gain access to error event records.

 (*) /dev/fr400cc_vdc_vsync [major 10, minor 245]

     This device file is an interface by which an application can be gain notification of VSYNC
     events on the VDC though poll and read.

 (*) /dev/fr400cc_vcc [major 10, minor 240]

     This device file is the main video capture interface.

 (*) /dev/fr400cc_vcc_vsync  [major 10, minor 241]

     This device file is an interface by which an application can be gain notification of VSYNC
     events on the VCC though poll and read.

 (*) /dev/fr400cc_i2s  [major 10, minor 250]


If the device files do not exist, the 'mknod' command may be used to create them:

  # mknod /dev/fr400cc_vdc c 10 244

or

  # mknod /dev/fr400cc_vdc_vsync c 10 245

