V4L/DVB (3376): Add cpia2 camera support

There has been a CPIA2 driver out of kernel for a long time and it has
been pretty clean for some time too. This is an import of the
sourceforge driver which has been stripped of
- 2.4 back compatibility
- 2.4 old style MJPEG ioctls
A couple of functions have been made static and the docs have been
repackaged into Documentation/video4linux.  The rvmalloc/free functions now
match the cpia driver again.  Other than that this is the code as is.
Tested on x86-64 with a QX5 microscope.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 130 insertions, 0 deletions

diff --git a/Documentation/video4linux/README.cpia2 b/Documentation/video4linux/README.cpia2
new file mode 100644
index 000000000000..f3bd3439ad91
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+++ b/Documentation/video4linux/README.cpia2
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+$Id: README,v 1.7 2005/08/29 23:39:57 sbertin Exp $
+
+1. Introduction
+
+	This is a driver for STMicroelectronics's CPiA2 (second generation
+Colour Processor Interface ASIC) based cameras. This camera outputs an MJPEG
+stream at up to vga size. It implements the Video4Linux interface as much as
+possible.  Since the V4L interface does not support compressed formats, only
+an mjpeg enabled application can be used with the camera. We have modified the
+gqcam application to view this stream.
+
+	The driver is implemented as two kernel modules. The cpia2 module
+contains the camera functions and the V4L interface.  The cpia2_usb module
+contains usb specific functions.  The main reason for this was the size of the
+module was getting out of hand, so I separted them.  It is not likely that
+there will be a parallel port version.
+
+FEATURES:
+   - Supports cameras with the Vision stv6410 (CIF) and stv6500 (VGA) cmos
+     sensors. I only have the vga sensor, so can't test the other.
+   - Image formats: VGA, QVGA, CIF, QCIF, and a number of sizes in between.
+     VGA and QVGA are the native image sizes for the VGA camera. CIF is done
+     in the coprocessor by scaling QVGA.  All other sizes are done by clipping.
+   - Palette: YCrCb, compressed with MJPEG.
+   - Some compression parameters are settable.
+   - Sensor framerate is adjustable (up to 30 fps CIF, 15 fps VGA).
+   - Adjust brightness, color, contrast while streaming.
+   - Flicker control settable for 50 or 60 Hz mains frequency.
+
+2. Making and installing the stv672 driver modules:
+
+	Requirements:
+	-------------
+	This should work with 2.4 (2.4.23 and later) and 2.6 kernels, but has
+only been tested on 2.6.  Video4Linux must be either compiled into the kernel or
+available as a module.  Video4Linux2 is automatically detected and made
+available at compile time.
+
+	Compiling:
+	----------
+	As root, do a make install.  This will compile and install the modules
+into the media/video directory in the module tree. For 2.4 kernels, use
+Makefile_2.4 (aka do make -f Makefile_2.4 install).
+
+	Setup:
+	------
+	Use 'modprobe cpia2' to load and 'modprobe -r cpia2' to unload. This
+may be done automatically by your distribution.
+
+3. Driver options
+
+	Option		Description
+	------		-----------
+	video_nr	video device to register (0=/dev/video0, etc)
+			range -1 to 64.  default is -1 (first available)
+			If you have more than 1 camera, this MUST be -1.
+	buffer_size	Size for each frame buffer in bytes (default 68k)
+	num_buffers	Number of frame buffers (1-32, default 3)
+	alternate	USB Alternate (2-7, default 7)
+	flicker_freq	Frequency for flicker reduction(50 or 60, default 60)
+	flicker_mode	0 to disable, or 1 to enable flicker reduction.
+			(default 0). This is only effective if the camera
+			uses a stv0672 coprocessor.
+
+	Setting the options:
+	--------------------
+	If you are using modules, edit /etc/modules.conf and add an options
+line like this:
+	options cpia2 num_buffers=3 buffer_size=65535
+
+	If the driver is compiled into the kernel, at boot time specify them
+like this:
+	cpia2=num_buffers:3,buffer_size:65535
+
+	What buffer size should I use?
+	------------------------------
+	The maximum image size depends on the alternate you choose, and the
+frame rate achieved by the camera.  If the compression engine is able to
+keep up with the frame rate, the maximum image size is given by the table
+below.
+	The compression engine starts out at maximum compression, and will
+increase image quality until it is close to the size in the table.  As long
+as the compression engine can keep up with the frame rate, after a short time
+the images will all be about the size in the table, regardless of resolution.
+	At low alternate settings, the compression engine may not be able to
+compress the image enough and will reduce the frame rate by producing larger
+images.
+	The default of 68k should be good for most users.  This will handle
+any alternate at frame rates down to 15fps.  For lower frame rates, it may
+be necessary to increase the buffer size to avoid having frames dropped due
+to insufficient space.
+
+			     Image size(bytes)
+	Alternate  bytes/ms   15fps    30fps
+	    2         128      8533     4267
+	    3         384     25600    12800
+	    4         640     42667    21333
+	    5         768     51200    25600
+	    6         896     59733    29867
+	    7        1023     68200    34100
+
+	How many buffers should I use?
+	------------------------------
+	For normal streaming, 3 should give the best results.  With only 2,
+it is possible for the camera to finish sending one image just after a
+program has started reading the other.  If this happens, the driver must drop
+a frame.  The exception to this is if you have a heavily loaded machine.  In
+this case use 2 buffers.  You are probably not reading at the full frame rate.
+If the camera can send multiple images before a read finishes, it could
+overwrite the third buffer before the read finishes, leading to a corrupt
+image.  Single and double buffering have extra checks to avoid overwriting.
+
+4. Using the camera
+
+	We are providing a modified gqcam application to view the output. In
+order to avoid confusion, here it is called mview.  There is also the qx5view
+program which can also control the lights on the qx5 microscope. MJPEG Tools
+(http://mjpeg.sourceforge.net) can also be used to record from the camera.
+
+5. Notes to developers:
+
+   - This is a driver version stripped of the 2.4 back compatibility
+     and old MJPEG ioctl API. See cpia2.sf.net for 2.4 support.
+
+6. Thanks:
+
+   - Peter Pregler <Peter_Pregler@email.com>,
+     Scott J. Bertin <scottbertin@yahoo.com>, and
+     Jarl Totland <Jarl.Totland@bdc.no> for the original cpia driver, which
+     this one was modelled from.