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                   W996[87]CF JPEG USB Dual Mode Camera Chip
                        Linux 2.4 driver (basic version)
                   =========================================

                               - Documentation -


Index
=====
1. Copyright
2. License
3. Overview
4. Supported devices
5. Module dependencies
6. Module loading
7. Module paramaters
8. Credits


1. Copyright
============
Copyright (C) 2002 2003 by Luca Risolia <luca.risolia@studio.unibo.it>


2. License
==========
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.


3. Overview
===========
This driver supports the video streaming capabilities of the devices mounting
Winbond W9967CF and Winbond W9968CF JPEG USB Dual Mode Camera Chips, when they
are being commanded by USB.

The full-featured driver is divided into two modules: the basic one, "w9968cf",
is needed for the supported devices to work; the second one, "w9968cf-vpp",
is an optional module, which provides some useful video post-processing
functions like video decoding, up-scaling and colour conversions. Once the
driver is installed, every time an application tries to open a recognized
device, "w9968cf" checks the presence of the "w9968cf-vpp" module and loads it
automatically by default.

Please keep in mind that official kernels do NOT include the second module for
performance purposes. However it is always recommended to download and install
the latest and complete release of the driver, replacing the existing one, if
present: it will be still even possible not to load the "w9968cf-vpp" module at
all, if you ever want to. Another important missing feature of the version in
the official Linux 2.4 kernels is the writeable /proc filesystem interface.

The latest and full-featured version of the W996[87]CF driver can be found at:
http://go.lamarinapunto.com/

Up to 32 cameras can be handled at the same time. They can be connected and
disconnected from the host many times without turning off the computer, if
your system supports the hotplug facility.

To change the default settings for each camera, many paramaters can be passed
through command line when the module is loaded into memory.

The driver relies on the Video4Linux, USB and I2C core modules of the official
Linux kernels, version 2.4.19 or greater, and is not compatible in any way with
previous versions. It has been designed to run properly on SMP systems as well.
At the moment, an additional module, "ovcamchip", is mandatory; it provides
support for some OmniVision CMOS sensors connected to the W996[87]CF chips.

The "ovcamchip" module is part of the OV511 driver, version 2.27, which can be
downloaded from internet:
http://alpha.dyndns.org/ov511/
To know how to compile it, read the documentation included in the OV511 
package.


4. Supported devices
====================
At the moment, known W996[87]CF based devices are:
- Aroma Digi Pen ADG-5000 Refurbished
- AVerTV USB
- Creative Labs Video Blaster WebCam Go
- Creative Labs Video Blaster WebCam Go Plus
- Die Lebon LDC-D35A Digital Kamera
- Ezonics EZ-802 EZMega Cam
- OPCOM Digi Pen VGA Dual Mode Pen Camera

If you know any other W996[87]CF based cameras, please contact me.

The list above does NOT imply that all those devices work with this driver: up
until now only webcams that have a CMOS sensor supported by the "ovcamchip"
module work. 
For a list of supported CMOS sensors, please visit the the author's homepage on
this module: http://alpha.dyndns.org/ov511/

Possible external microcontrollers of those webcams are not supported: this
means that still images cannot be downloaded from the device memory.

Furthermore, it's worth to note that I was only able to run tests on my
"Creative Labs Video Blaster WebCam Go". Donations of other models, for
additional testing and full support, would be much appreciated.


5. Module dependencies
======================
The driver needs kernel support for Video4Linux, USB and I2C, and a third-party
module for the CMOS sensor.

The following options of the kernel configuration file must be enabled and
corresponding modules must be compiled:

        # Multimedia devices
        #
        CONFIG_VIDEO_DEV=m

        # I2C support
        #
        CONFIG_I2C=m

The I2C core module can be compiled statically in the kernel as well.

        # USB support
        #
        CONFIG_USB=m

In addition, depending on the hardware being used, only one of the modules
below is necessary:

        # USB Host Controller Drivers
        #
        CONFIG_USB_EHCI_HCD=m
        CONFIG_USB_UHCI=m
        CONFIG_USB_UHCI_ALT=m
        CONFIG_USB_OHCI=m

And finally:

        # USB Multimedia devices
        #
        CONFIG_USB_W9968CF=m

Also, make sure "Enforce bandwidth allocation" is NOT enabled.

The /proc filesystem can be optionally built into the kernel:

        # File systems
        #
        CONFIG_PROC_FS=y

        # Video For Linux
        #
        CONFIG_VIDEO_PROC_FS=y

The last module we need is "ovcamchip.o". To obtain it, you have to download
the OV511, version 2.27 - don't use other versions - and compile it according
to its documentation. 
The package is available at http://alpha.dyndns.org/ov511/ .


6. Module loading
=================
To use the driver, it is necessary to load the "w9968cf" module into memory
after every other module required: for the 2.4 series of the kernel, they are
named, in order: "videodev", "usbcore", then "ehci-hcd", "usb-uhci", "uhci",
"usb-ohci" (just one), and also "i2c-core" and "ovcamchip".

Loading can be done this way, from root:

        [root@localhost home]# modprobe i2c-core
        [root@localhost ov511-x.xx]# insmod ./ovcamchip.o
        [root@localhost home]# modprobe w9968cf

At this point the devices should be recognized. There are two ways of verifying
that the loading process has gone well: the first is to analyze kernel 
messages:

        [user@localhost home]$ dmesg

A second way is to retrieve informations from the entries that have just been
created in the /proc/video/w9968cf/ directory; this feature works if and only
if the kernel has been built with the /proc filesystem support.
As an example, the following command will print the list of registered cameras:

        [user@localhost home]$ cat /proc/video/w9968cf/global

There are a lot of parameters the module can use to change the default
settings for each device. To list every possible parameter with a brief
explanation about them and which syntax to use, it is recommended to run the
"modinfo" command:

        [root@locahost home]# modinfo w9968cf


7. Module paramaters
====================
Module paramaters are listed below:
-------------------------------------------------------------------------------
Name:           vppmod_load
Type:           bool
Syntax:         <0|1>
Description:    Automatic 'w9968cf-vpp' module loading: 0 disabled, 1 enabled.
                If enabled, every time an application attempts to open a
                camera, 'insmod' searches for the video post-processing module
                in the system and loads it automatically (if present).
                The 'w9968cf-vpp' module adds extra image manipulation 
                capabilities to the 'w9968cf' module,like software up-scaling,
                colour conversions and video decoding.
Default:        1
-------------------------------------------------------------------------------
Name:           simcams 
Type:           int 
Syntax:         <n> 
Description:    Number of cameras allowed to stream simultaneously.
                n may vary from 0 to 32.
Default:        32
-------------------------------------------------------------------------------
Name:           video_nr
Type:           int array (min = 0, max = 32)
Syntax:         <-1|n[,...]> 
Description:    Specify V4L minor mode number.
                -1 = use next available
                 n = use minor number n
                You can specify 32 cameras this way.
                For example:
                video_nr=-1,2,-1 would assign minor number 2 to the second
                recognized camera and use auto for the first one and for every
                other camera.
Default:        -1
-------------------------------------------------------------------------------
Name:           packet_size
Type:           int array (min = 0, max = 32)
Syntax:         <n[,...]> 
Description:    Specify the maximum data payload size in bytes for alternate
                settings, for each device. n is scaled between 63 and 1023.
Default:        1023
-------------------------------------------------------------------------------
Name:           max_buffers
Type:           int array (min = 0, max = 32)
Syntax:         <n[,...]>
Description:    For advanced users.
                Specify the maximum number of video frame buffers to allocate
                for each device, from 2 to 32.
Default:        2
-------------------------------------------------------------------------------
Name:           double_buffer
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    Hardware double buffering: 0 disabled, 1 enabled.
                It should be enabled if you want smooth video output: if you
                obtain out of sync. video, disable it, or try to
                decrease the 'clockdiv' module paramater value.
Default:        1 for every device.
-------------------------------------------------------------------------------
Name:           clamping
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    Video data clamping: 0 disabled, 1 enabled.
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           filter_type
Type:           int array (min = 0, max = 32)
Syntax:         <0|1|2[,...]> 
Description:    Video filter type.
                0 none, 1 (1-2-1) 3-tap filter, 2 (2-3-6-3-2) 5-tap filter.
                The filter is used to reduce noise and aliasing artifacts
                produced by the CCD or CMOS sensor.
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           largeview
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    Large view: 0 disabled, 1 enabled.
Default:        1 for every device.
-------------------------------------------------------------------------------
Name:           upscaling
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    Software scaling (for non-compressed video only):
                0 disabled, 1 enabled.
                Disable it if you have a slow CPU or you don't have enough
                memory.
Default:        0 for every device.
Note:           If 'w9968cf-vpp' is not loaded, this paramater is set to 0.
-------------------------------------------------------------------------------
Name:           decompression
Type:           int array (min = 0, max = 32)
Syntax:         <0|1|2[,...]>
Description:    Software video decompression:
                0 = disables decompression
                    (doesn't allow formats needing decompression).
                1 = forces decompression
                    (allows formats needing decompression only).
                2 = allows any permitted formats.
                Formats supporting (de)compressed video are YUV422P and
                YUV420P/YUV420 in any resolutions where width and height are
                multiples of 16.
Default:        2 for every device.
Note:           If 'w9968cf-vpp' is not loaded, forcing decompression is not
                allowed; in this case this paramater is set to 2.
-------------------------------------------------------------------------------
Name:           force_palette
Type:           int array (min = 0, max = 32)
Syntax:         <0|9|10|13|15|8|7|1|6|3|4|5[,...]>
Description:    Force picture palette.
                In order:
                 0 = Off - allows any of the following formats:
                 9 = UYVY    16 bpp - Original video, compression disabled
                10 = YUV420  12 bpp - Original video, compression enabled
                13 = YUV422P 16 bpp - Original video, compression enabled
                15 = YUV420P 12 bpp - Original video, compression enabled
                 8 = YUVY    16 bpp - Software conversion from UYVY
                 7 = YUV422  16 bpp - Software conversion from UYVY
                 1 = GREY     8 bpp - Software conversion from UYVY
                 6 = RGB555  16 bpp - Software conversion from UYVY
                 3 = RGB565  16 bpp - Software conversion from UYVY
                 4 = RGB24   24 bpp - Software conversion from UYVY
                 5 = RGB32   32 bpp - Software conversion from UYVY
                When not 0, this paramater will override 'decompression'.
Default:        0 for every device. Initial palette is 9 (UYVY).
Note:           If 'w9968cf-vpp' is not loaded, this paramater is set to 9.
-------------------------------------------------------------------------------
Name:           force_rgb
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]>
Description:    Read RGB video data instead of BGR:
                1 = use RGB component ordering.
                0 = use BGR component ordering.
                This parameter has effect when using RGBX palettes only.
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           autobright
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]>
Description:    CMOS sensor automatically changes brightness:
                0 = no, 1 = yes
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           autoexp
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]>
Description:    CMOS sensor automatically changes exposure:
                0 = no, 1 = yes
Default:        1 for every device.
-------------------------------------------------------------------------------
Name:           lightfreq
Type:           int array (min = 0, max = 32)
Syntax:         <50|60[,...]>
Description:    Light frequency in Hz:
                50 for European and Asian lighting, 60 for American lighting.
Default:        50 for every device.
-------------------------------------------------------------------------------
Name:           bandingfilter
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    Banding filter to reduce effects of fluorescent 
                lighting:
                0 disabled, 1 enabled.
                This filter tries to reduce the pattern of horizontal
                light/dark bands caused by some (usually fluorescent) lighting.
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           clockdiv
Type:           int array (min = 0, max = 32)
Syntax:         <-1|n[,...]>
Description:    Force pixel clock divisor to a specific value (for experts):
                n may vary from 0 to 127.
                -1 for automatic value.
                See also the 'double_buffer' module paramater.
Default:        -1 for every device.
-------------------------------------------------------------------------------
Name:           backlight
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]>
Description:    Objects are lit from behind:
                0 = no, 1 = yes
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           mirror
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]>
Description:    Reverse image horizontally:
                0 = no, 1 = yes
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           monochrome
Type:           bool array (min = 0, max = 32)
Syntax:         <0|1[,...]> 
Description:    The CMOS sensor is monochrome:
                0 = no, 1 = yes
Default:        0 for every device.
-------------------------------------------------------------------------------
Name:           brightness
Type:           long array (min = 0, max = 32)
Syntax:         <n[,...]>
Description:    Set picture brightness (0-65535).
                This parameter has no effect if 'autobright' is enabled.
Default:        31000 for every device.
-------------------------------------------------------------------------------
Name:           hue
Type:           long array (min = 0, max = 32)
Syntax:         <n[,...]>
Description:    Set picture hue (0-65535).
Default:        32768 for every device.
-------------------------------------------------------------------------------
Name:           colour
Type:           long array (min = 0, max = 32)
Syntax:         <n[,...]>
Description:    Set picture saturation (0-65535).
Default:        32768 for every device.
-------------------------------------------------------------------------------
Name:           contrast
Type:           long array (min = 0, max = 32)
Syntax:         <n[,...]> 
Description:    Set picture contrast (0-65535).
Default:        50000 for every device.
-------------------------------------------------------------------------------
Name:           whiteness
Type:           long array (min = 0, max = 32)
Syntax:         <n[,...]> 
Description:    Set picture whiteness (0-65535).
Default:        32768 for every device.
-------------------------------------------------------------------------------
Name:           debug
Type:           int
Syntax:         <n> 
Description:    Debugging information level, from 0 to 6:
                0 = none (use carefully)
                1 = critical errors
                2 = significant informations
                3 = configuration or general messages
                4 = warnings
                5 = called functions
                6 = function internals
                Level 5 and 6 are useful for testing only, when just one
                device is used.
Default:        2
-------------------------------------------------------------------------------
Name:           specific_debug
Type:           bool
Syntax:         <0|1>
Description:    Enable or disable specific debugging messages:
                0 = print messages concerning every level <= 'debug' level.
                1 = print messages concerning the level indicated by 'debug'.
Default:        0
-------------------------------------------------------------------------------


8. Credits
==========
The development would not have proceed much further without having looked at
the source code of other drivers and without the help of several persons; in
particular:

- the I2C interface to kernel and high-level CMOS sensor control routines have
  been taken from the OV511 driver by Mark McClelland;

- memory management code has been copied from the bttv driver by Ralph Metzler,
  Marcus Metzler and Gerd Knorr;

- the low-level I2C read function has been written by Frederic Jouault;

- the low-level I2C fast write function has been written by Piotr Czerczak.