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diff --git a/Documentation/usb/zc0301.txt b/Documentation/usb/zc0301.txt new file mode 100644 index 0000000..f55262c --- /dev/null +++ b/Documentation/usb/zc0301.txt @@ -0,0 +1,254 @@ + + ZC0301 Image Processor and Control Chip + Driver for Linux + ======================================= + + - Documentation - + + +Index +===== +1. Copyright +2. Disclaimer +3. License +4. Overview and features +5. Module dependencies +6. Module loading +7. Module parameters +8. Supported devices +9. Notes for V4L2 application developers +10. Contact information +11. Credits + + +1. Copyright +============ +Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it> + + +2. Disclaimer +============= +This software is not developed or sponsored by Z-Star Microelectronics Corp. +Trademarks are property of their respective owner. + + +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 and features +======================== +This driver supports the video interface of the devices mounting the ZC0301 +Image Processor and Control Chip. + +The driver relies on the Video4Linux2 and USB core modules. It has been +designed to run properly on SMP systems as well. + +The latest version of the ZC0301 driver can be found at the following URL: +http://www.linux-projects.org/ + +Some of the features of the driver are: + +- full compliance with the Video4Linux2 API (see also "Notes for V4L2 + application developers" paragraph); +- available mmap or read/poll methods for video streaming through isochronous + data transfers; +- automatic detection of image sensor; +- video format is standard JPEG; +- dynamic driver control thanks to various module parameters (see "Module + parameters" paragraph); +- up to 64 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 + the system supports hotplugging; + + +5. Module dependencies +====================== +For it to work properly, the driver needs kernel support for Video4Linux and +USB. + +The following options of the kernel configuration file must be enabled and +corresponding modules must be compiled: + + # Multimedia devices + # + CONFIG_VIDEO_DEV=m + + # USB support + # + CONFIG_USB=m + +In addition, depending on the hardware being used, the modules below are +necessary: + + # USB Host Controller Drivers + # + CONFIG_USB_EHCI_HCD=m + CONFIG_USB_UHCI_HCD=m + CONFIG_USB_OHCI_HCD=m + +The ZC0301 controller also provides a built-in microphone interface. It is +supported by the USB Audio driver thanks to the ALSA API: + + # Sound + # + CONFIG_SOUND=y + + # Advanced Linux Sound Architecture + # + CONFIG_SND=m + + # USB devices + # + CONFIG_SND_USB_AUDIO=m + +And finally: + + # USB Multimedia devices + # + CONFIG_USB_ZC0301=m + + +6. Module loading +================= +To use the driver, it is necessary to load the "zc0301" module into memory +after every other module required: "videodev", "usbcore" and, depending on +the USB host controller you have, "ehci-hcd", "uhci-hcd" or "ohci-hcd". + +Loading can be done as shown below: + + [root@localhost home]# modprobe zc0301 + +At this point the devices should be recognized. You can invoke "dmesg" to +analyze kernel messages and verify that the loading process has gone well: + + [user@localhost home]$ dmesg + + +7. Module parameters +==================== +Module parameters are listed below: +------------------------------------------------------------------------------- +Name: video_nr +Type: short array (min = 0, max = 64) +Syntax: <-1|n[,...]> +Description: Specify V4L2 minor mode number: + -1 = use next available + n = use minor number n + You can specify up to 64 cameras this way. + For example: + video_nr=-1,2,-1 would assign minor number 2 to the second + registered camera and use auto for the first one and for every + other camera. +Default: -1 +------------------------------------------------------------------------------- +Name: force_munmap +Type: bool array (min = 0, max = 64) +Syntax: <0|1[,...]> +Description: Force the application to unmap previously mapped buffer memory + before calling any VIDIOC_S_CROP or VIDIOC_S_FMT ioctl's. Not + all the applications support this feature. This parameter is + specific for each detected camera. + 0 = do not force memory unmapping + 1 = force memory unmapping (save memory) +Default: 0 +------------------------------------------------------------------------------- +Name: frame_timeout +Type: uint array (min = 0, max = 64) +Syntax: <n[,...]> +Description: Timeout for a video frame in seconds. This parameter is + specific for each detected camera. This parameter can be + changed at runtime thanks to the /sys filesystem interface. +Default: 2 +------------------------------------------------------------------------------- +Name: debug +Type: ushort +Syntax: <n> +Description: Debugging information level, from 0 to 3: + 0 = none (use carefully) + 1 = critical errors + 2 = significant informations + 3 = more verbose messages + Level 3 is useful for testing only, when only one device + is used at the same time. It also shows some more informations + about the hardware being detected. This module parameter can be + changed at runtime thanks to the /sys filesystem interface. +Default: 2 +------------------------------------------------------------------------------- + + +8. Supported devices +==================== +None of the names of the companies as well as their products will be mentioned +here. They have never collaborated with the author, so no advertising. + +From the point of view of a driver, what unambiguously identify a device are +its vendor and product USB identifiers. Below is a list of known identifiers of +devices mounting the ZC0301 Image Processor and Control Chips: + +Vendor ID Product ID +--------- ---------- +0x041e 0x4017 +0x041e 0x401c +0x041e 0x401e +0x041e 0x4034 +0x041e 0x4035 +0x046d 0x08ae +0x0ac8 0x0301 +0x10fd 0x8050 + +The list above does not imply that all those devices work with this driver: up +until now only the ones that mount the following image sensors are supported; +kernel messages will always tell you whether this is the case: + +Model Manufacturer +----- ------------ +PAS202BCB PixArt Imaging, Inc. + + +9. Notes for V4L2 application developers +======================================== +This driver follows the V4L2 API specifications. In particular, it enforces two +rules: + +- exactly one I/O method, either "mmap" or "read", is associated with each +file descriptor. Once it is selected, the application must close and reopen the +device to switch to the other I/O method; + +- although it is not mandatory, previously mapped buffer memory should always +be unmapped before calling any "VIDIOC_S_CROP" or "VIDIOC_S_FMT" ioctl's. +The same number of buffers as before will be allocated again to match the size +of the new video frames, so you have to map the buffers again before any I/O +attempts on them. + + +10. Contact information +======================= +The author may be contacted by e-mail at <luca.risolia@studio.unibo.it>. + +GPG/PGP encrypted e-mail's are accepted. The GPG key ID of the author is +'FCE635A4'; the public 1024-bit key should be available at any keyserver; +the fingerprint is: '88E8 F32F 7244 68BA 3958 5D40 99DA 5D2A FCE6 35A4'. + + +11. Credits +=========== +- Informations about the chip internals needed to enable the I2C protocol have + been taken from the documentation of the ZC030x Video4Linux1 driver written + by Andrew Birkett <andy@nobugs.org>; +- The initialization values of the ZC0301 controller connected to the PAS202BCB + image sensor have been taken from the SPCA5XX driver maintained by + Michel Xhaard <mxhaard@magic.fr>. |