w9968cf.txt

linux 内核源代码

		   W996[87]CF JPEG USB Dual Mode Camera Chip
		     Driver for Linux 2.6 (basic version)
		   =========================================

			       - Documentation -


Index
=====
1.  Copyright
2.  Disclaimer
3.  License
4.  Overview
5.  Supported devices
6.  Module dependencies
7.  Module loading
8.  Module parameters
9.  Contact information
10. Credits


1. Copyright
============
Copyright (C) 2002-2004 by Luca Risolia <[e-mail]>


2. Disclaimer
=============
Winbond is a trademark of Winbond Electronics Corporation.
This software is not sponsored or developed by Winbond.


3. 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.


4. Overview
===========
This driver supports the video streaming capabilities of the devices mounting
Winbond W9967CF and Winbond W9968CF JPEG USB Dual Mode Camera Chips. OV681
based cameras should be supported as well.

The 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.

Note that the official kernels do neither include nor support the second
module for performance purposes. Therefore, it is always recommended to
download and install the latest and complete release of the driver,
replacing the existing one, if present.

The latest and full-featured version of the W996[87]CF driver can be found at:
http://www.linux-projects.org. Please refer to the documentation included in
that package, if you are going to use it.

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 parameters can be passed
through command line when the module is loaded into memory.

The driver relies on the Video4Linux, USB and I2C core modules. It has been
designed to run properly on SMP systems as well. An additional module,
"ovcamchip", is mandatory; it provides support for some OmniVision image
sensors connected to the W996[87]CF chips; if found in the system, the module
will be automatically loaded by default (provided that the kernel has been
compiled with the automatic module loading option).


5. Supported devices
====================
At the moment, known W996[87]CF and OV681 based devices are:
- Aroma Digi Pen VGA Dual Mode ADG-5000 (unknown image sensor)
- AVerMedia AVerTV USB (SAA7111A, Philips FI1216Mk2 tuner, PT2313L audio chip)
- Creative Labs Video Blaster WebCam Go (OmniVision OV7610 sensor)
- Creative Labs Video Blaster WebCam Go Plus (OmniVision OV7620 sensor)
- Lebon LDC-035A (unknown image sensor)
- Ezonics EZ-802 EZMega Cam (OmniVision OV8610C sensor)
- OmniVision OV8610-EDE (OmniVision OV8610 sensor)
- OPCOM Digi Pen VGA Dual Mode Pen Camera (unknown image sensor)
- Pretec Digi Pen-II (OmniVision OV7620 sensor)
- Pretec DigiPen-480 (OmniVision OV8610 sensor)

If you know any other W996[87]CF or OV681 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 an image sensor supported by the "ovcamchip"
module work. Kernel messages will always tell you whether this is case.

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.


6. Module dependencies
======================
For it to work properly, the driver needs kernel support for Video4Linux, USB
and I2C, and the "ovcamchip" module for the image sensor. Make sure you are not
actually using any external "ovcamchip" module, given that the W996[87]CF
driver depends on the version of the module present in the official kernels.

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.

	# OmniVision Camera Chip support
	#
	CONFIG_VIDEO_OVCAMCHIP=m

	# 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_HCD=m
	CONFIG_USB_OHCI_HCD=m

And finally:

	# USB Multimedia devices
	#
	CONFIG_USB_W9968CF=m


7. Module loading
=================
To use the driver, it is necessary to load the "w9968cf" module into memory
after every other module required.

Loading can be done this way, from root:

	[root@localhost home]# modprobe usbcore
	[root@localhost home]# modprobe i2c-core
	[root@localhost home]# modprobe videodev
	[root@localhost home]# modprobe w9968cf

At this point the pertinent devices should be recognized: "dmesg" can be used
to analyze kernel messages:

	[user@localhost home]$ dmesg

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


8. Module parameters
====================
Module parameters are listed below:
-------------------------------------------------------------------------------
Name:            ovmod_load
Type:            bool
Syntax:          <0|1>
Description:     Automatic 'ovcamchip' module loading: 0 disabled, 1 enabled.
		 If enabled, 'insmod' searches for the required 'ovcamchip'
		 module in the system, according to its configuration, and
		 loads that module automatically. This action is performed as
		 once soon as the 'w9968cf' module is loaded into memory.
Default:         1
Note:            The kernel must be compiled with the CONFIG_KMOD option
		 enabled for the 'ovcamchip' module to be loaded and for
		 this parameter to be present.
-------------------------------------------------------------------------------
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 up to 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