2 ZC0301 Image Processor and Control Chip
4 =======================================
14 4. Overview and features
15 5. Module dependencies
19 9. Notes for V4L2 application developers
20 10. Contact information
26 Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>
31 This software is not developed or sponsored by Z-Star Microelectronics Corp.
32 Trademarks are property of their respective owner.
37 This program is free software; you can redistribute it and/or modify
38 it under the terms of the GNU General Public License as published by
39 the Free Software Foundation; either version 2 of the License, or
40 (at your option) any later version.
42 This program is distributed in the hope that it will be useful,
43 but WITHOUT ANY WARRANTY; without even the implied warranty of
44 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
45 GNU General Public License for more details.
47 You should have received a copy of the GNU General Public License
48 along with this program; if not, write to the Free Software
49 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
52 4. Overview and features
53 ========================
54 This driver supports the video interface of the devices mounting the ZC0301
55 Image Processor and Control Chip.
57 The driver relies on the Video4Linux2 and USB core modules. It has been
58 designed to run properly on SMP systems as well.
60 The latest version of the ZC0301 driver can be found at the following URL:
61 http://www.linux-projects.org/
63 Some of the features of the driver are:
65 - full compliance with the Video4Linux2 API (see also "Notes for V4L2
66 application developers" paragraph);
67 - available mmap or read/poll methods for video streaming through isochronous
69 - automatic detection of image sensor;
70 - video formats is standard JPEG in various compression qualities
71 (see also "Notes for V4L2 application developers" paragraph);
72 - full support for the capabilities of every possible image sensors that can
73 be connected to the ZC0301 bridges, including, for istance, red, green,
74 blue and global gain adjustments and exposure control (see "Supported
75 devices" paragraph for details);
76 - use of default color settings for sunlight conditions;
77 - dynamic driver control thanks to various module parameters (see "Module
78 parameters" paragraph);
79 - up to 64 cameras can be handled at the same time; they can be connected and
80 disconnected from the host many times without turning off the computer, if
81 the system supports hotplugging;
84 5. Module dependencies
85 ======================
86 For it to work properly, the driver needs kernel support for Video4Linux and
89 The following options of the kernel configuration file must be enabled and
90 corresponding modules must be compiled:
100 In addition, depending on the hardware being used, the modules below are
103 # USB Host Controller Drivers
105 CONFIG_USB_EHCI_HCD=m
106 CONFIG_USB_UHCI_HCD=m
107 CONFIG_USB_OHCI_HCD=m
109 The ZC0301 controller also provides a built-in microphone interface. It is
110 supported by the USB Audio driver thanks to the ALSA API:
116 # Advanced Linux Sound Architecture
122 CONFIG_SND_USB_AUDIO=m
126 # USB Multimedia devices
133 To use the driver, it is necessary to load the "zc0301" module into memory
134 after every other module required: "videodev", "usbcore" and, depending on
135 the USB host controller you have, "ehci-hcd", "uhci-hcd" or "ohci-hcd".
137 Loading can be done as shown below:
139 [root@localhost home]# modprobe zc0301
141 At this point the devices should be recognized. You can invoke "dmesg" to
142 analyze kernel messages and verify that the loading process has gone well:
144 [user@localhost home]$ dmesg
149 Module parameters are listed below:
150 -------------------------------------------------------------------------------
152 Type: short array (min = 0, max = 64)
154 Description: Specify V4L2 minor mode number:
155 -1 = use next available
156 n = use minor number n
157 You can specify up to 64 cameras this way.
159 video_nr=-1,2,-1 would assign minor number 2 to the second
160 registered camera and use auto for the first one and for every
163 -------------------------------------------------------------------------------
165 Type: bool array (min = 0, max = 64)
167 Description: Force the application to unmap previously mapped buffer memory
168 before calling any VIDIOC_S_CROP or VIDIOC_S_FMT ioctl's. Not
169 all the applications support this feature. This parameter is
170 specific for each detected camera.
171 0 = do not force memory unmapping
172 1 = force memory unmapping (save memory)
174 -------------------------------------------------------------------------------
178 Description: Debugging information level, from 0 to 3:
179 0 = none (use carefully)
181 2 = significant informations
182 3 = more verbose messages
183 Level 3 is useful for testing only, when only one device
184 is used at the same time. It also shows some more informations
185 about the hardware being detected. This module parameter can be
186 changed at runtime thanks to the /sys filesystem interface.
188 -------------------------------------------------------------------------------
193 None of the names of the companies as well as their products will be mentioned
194 here. They have never collaborated with the author, so no advertising.
196 From the point of view of a driver, what unambiguously identify a device are
197 its vendor and product USB identifiers. Below is a list of known identifiers of
198 devices mounting the ZC0301 Image Processor and Control Chips:
204 The following image sensors are supported:
208 PAS202BCB PixArt Imaging, Inc.
210 All the available control settings of each image sensor are supported through
214 9. Notes for V4L2 application developers
215 ========================================
216 This driver follows the V4L2 API specifications. In particular, it enforces two
219 - exactly one I/O method, either "mmap" or "read", is associated with each
220 file descriptor. Once it is selected, the application must close and reopen the
221 device to switch to the other I/O method;
223 - although it is not mandatory, previously mapped buffer memory should always
224 be unmapped before calling any "VIDIOC_S_CROP" or "VIDIOC_S_FMT" ioctl's.
225 The same number of buffers as before will be allocated again to match the size
226 of the new video frames, so you have to map the buffers again before any I/O
229 This driver supports the standard JPEG video format. The current compression
230 quality may vary from 0 to 3 and can be selected or queried thanks to the
231 VIDIOC_S_JPEGCOMP and VIDIOC_G_JPEGCOMP V4L2 ioctl's.
234 10. Contact information
235 =======================
236 The author may be contacted by e-mail at <luca.risolia@studio.unibo.it>.
238 GPG/PGP encrypted e-mail's are accepted. The GPG key ID of the author is
239 'FCE635A4'; the public 1024-bit key should be available at any keyserver;
240 the fingerprint is: '88E8 F32F 7244 68BA 3958 5D40 99DA 5D2A FCE6 35A4'.
245 - Informations about the chip internals to enable the I2C protocol have been
246 taken from the documentation of the ZC030x Video4Linux1 driver written by
247 Andrew Birkett <andy@nobugs.org>;
248 - Initialization values of the ZC0301 connected to the PAS202BCB image sensor
249 have been taken from the SPCA5XX driver maintained by
250 Michel Xhaard <mxhaard@magic.fr>