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authorHans Verkuil <hans.verkuil@cisco.com>2013-12-12 07:35:22 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2013-12-20 13:41:36 -0200
commitb8da9d3aaff26edcdf88751c6d2763f4337c79e3 (patch)
tree6f97a4a7eedc1a7fbb1c42b28462997dce7081da /Documentation/video4linux
parent4bf48150541b5f3335a6438f51b75f9d9d95e256 (diff)
downloadkernel-b8da9d3aaff26edcdf88751c6d2763f4337c79e3.tar.gz
[media] sn9c102: prepare for removal by moving it to staging
During the last media summit meeting it was decided to move this driver to staging as the first step to removing it altogether. Most webcams covered by this driver are now supported by gspca. Nobody has the hardware to convert the remaining devices to gspca. This driver needs a major overhaul to have it conform to the latest frameworks and compliancy tests. Without hardware, however, this is next to impossible. Given the fact that this driver seems to be pretty much unused (it has been removed from Fedora several versions ago and nobody complained about that), we decided to drop this driver. This patch moves it to staging. Some time in 2014 we will drop it completely. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: Hans de Goede <hdegoede@redhat.com> Cc: Luca Risolia <luca.risolia@studio.unibo.it> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
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-
- SN9C1xx PC Camera Controllers
- 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. Optional device control through "sysfs"
-9. Supported devices
-10. Notes for V4L2 application developers
-11. Video frame formats
-12. Contact information
-13. Credits
-
-
-1. Copyright
-============
-Copyright (C) 2004-2007 by Luca Risolia <luca.risolia@studio.unibo.it>
-
-
-2. Disclaimer
-=============
-SONiX is a trademark of SONiX Technology Company Limited, inc.
-This software is not sponsored or developed by SONiX.
-
-
-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 attempts to support the video interface of the devices assembling
-the SONiX SN9C101, SN9C102, SN9C103, SN9C105 and SN9C120 PC Camera Controllers
-("SN9C1xx" from now on).
-
-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 SN9C1xx 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;
-- support for built-in microphone interface;
-- support for any window resolutions and optional panning within the maximum
- pixel area of image sensor;
-- image downscaling with arbitrary scaling factors from 1, 2 and 4 in both
- directions (see "Notes for V4L2 application developers" paragraph);
-- two different video formats for uncompressed or compressed data in low or
- high compression quality (see also "Notes for V4L2 application developers"
- and "Video frame formats" paragraphs);
-- full support for the capabilities of many of the possible image sensors that
- can be connected to the SN9C1xx bridges, including, for instance, red, green,
- blue and global gain adjustments and exposure (see "Supported devices"
- paragraph for details);
-- use of default color settings for sunlight conditions;
-- dynamic I/O interface for both SN9C1xx and image sensor control and
- monitoring (see "Optional device control through 'sysfs'" paragraph);
-- 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;
-- no known bugs.
-
-
-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
-
-To enable advanced debugging functionality on the device through /sysfs:
-
- # Multimedia devices
- #
- CONFIG_VIDEO_ADV_DEBUG=y
-
- # 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 SN9C103, SN9c105 and SN9C120 controllers also provide 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_SN9C102=m
-
-
-6. Module loading
-=================
-To use the driver, it is necessary to load the "sn9c102" module into memory
-after every other module required: "videodev", "v4l2_common", "compat_ioctl32",
-"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 sn9c102
-
-Note that the module is called "sn9c102" for historic reasons, although it
-does not just support the SN9C102.
-
-At this point all the devices supported by the driver and connected to the USB
-ports should be recognized. You can invoke "dmesg" to analyze kernel messages
-and verify that the loading process has gone well:
-
- [user@localhost home]$ dmesg
-
-or, to isolate all the kernel messages generated by the driver:
-
- [user@localhost home]$ dmesg | grep sn9c102
-
-
-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
- recognized 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: <0|n[,...]>
-Description: Timeout for a video frame in seconds before returning an I/O
- error; 0 for infinity. This parameter is specific for each
- detected camera and 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 information
- 3 = more verbose messages
- Level 3 is useful for testing only. It also shows some more
- information about the hardware being detected.
- This parameter can be changed at runtime thanks to the /sys
- filesystem interface.
-Default: 2
--------------------------------------------------------------------------------
-
-
-8. Optional device control through "sysfs" [1]
-==========================================
-If the kernel has been compiled with the CONFIG_VIDEO_ADV_DEBUG option enabled,
-it is possible to read and write both the SN9C1xx and the image sensor
-registers by using the "sysfs" filesystem interface.
-
-Every time a supported device is recognized, a write-only file named "green" is
-created in the /sys/class/video4linux/videoX directory. You can set the green
-channel's gain by writing the desired value to it. The value may range from 0
-to 15 for the SN9C101 or SN9C102 bridges, from 0 to 127 for the SN9C103,
-SN9C105 and SN9C120 bridges.
-Similarly, only for the SN9C103, SN9C105 and SN9C120 controllers, blue and red
-gain control files are available in the same directory, for which accepted
-values may range from 0 to 127.
-
-There are other four entries in the directory above for each registered camera:
-"reg", "val", "i2c_reg" and "i2c_val". The first two files control the
-SN9C1xx bridge, while the other two control the sensor chip. "reg" and
-"i2c_reg" hold the values of the current register index where the following
-reading/writing operations are addressed at through "val" and "i2c_val". Their
-use is not intended for end-users. Note that "i2c_reg" and "i2c_val" will not
-be created if the sensor does not actually support the standard I2C protocol or
-its registers are not 8-bit long. Also, remember that you must be logged in as
-root before writing to them.
-
-As an example, suppose we were to want to read the value contained in the
-register number 1 of the sensor register table - which is usually the product
-identifier - of the camera registered as "/dev/video0":
-
- [root@localhost #] cd /sys/class/video4linux/video0
- [root@localhost #] echo 1 > i2c_reg
- [root@localhost #] cat i2c_val
-
-Note that "cat" will fail if sensor registers cannot be read.
-
-Now let's set the green gain's register of the SN9C101 or SN9C102 chips to 2:
-
- [root@localhost #] echo 0x11 > reg
- [root@localhost #] echo 2 > val
-
-Note that the SN9C1xx always returns 0 when some of its registers are read.
-To avoid race conditions, all the I/O accesses to the above files are
-serialized.
-The sysfs interface also provides the "frame_header" entry, which exports the
-frame header of the most recent requested and captured video frame. The header
-is always 18-bytes long and is appended to every video frame by the SN9C1xx
-controllers. As an example, this additional information can be used by the user
-application for implementing auto-exposure features via software.
-
-The following table describes the frame header exported by the SN9C101 and
-SN9C102:
-
-Byte # Value or bits Description
------- ------------- -----------
-0x00 0xFF Frame synchronisation pattern
-0x01 0xFF Frame synchronisation pattern
-0x02 0x00 Frame synchronisation pattern
-0x03 0xC4 Frame synchronisation pattern
-0x04 0xC4 Frame synchronisation pattern
-0x05 0x96 Frame synchronisation pattern
-0x06 [3:0] Read channel gain control = (1+R_GAIN/8)
- [7:4] Blue channel gain control = (1+B_GAIN/8)
-0x07 [ 0 ] Compression mode. 0=No compression, 1=Compression enabled
- [2:1] Maximum scale factor for compression
- [ 3 ] 1 = USB fifo(2K bytes) is full
- [ 4 ] 1 = Digital gain is finish
- [ 5 ] 1 = Exposure is finish
- [7:6] Frame index
-0x08 [7:0] Y sum inside Auto-Exposure area (low-byte)
-0x09 [7:0] Y sum inside Auto-Exposure area (high-byte)
- where Y sum = (R/4 + 5G/16 + B/8) / 32
-0x0A [7:0] Y sum outside Auto-Exposure area (low-byte)
-0x0B [7:0] Y sum outside Auto-Exposure area (high-byte)
- where Y sum = (R/4 + 5G/16 + B/8) / 128
-0x0C 0xXX Not used
-0x0D 0xXX Not used
-0x0E 0xXX Not used
-0x0F 0xXX Not used
-0x10 0xXX Not used
-0x11 0xXX Not used
-
-The following table describes the frame header exported by the SN9C103:
-
-Byte # Value or bits Description
------- ------------- -----------
-0x00 0xFF Frame synchronisation pattern
-0x01 0xFF Frame synchronisation pattern
-0x02 0x00 Frame synchronisation pattern
-0x03 0xC4 Frame synchronisation pattern
-0x04 0xC4 Frame synchronisation pattern
-0x05 0x96 Frame synchronisation pattern
-0x06 [6:0] Read channel gain control = (1/2+R_GAIN/64)
-0x07 [6:0] Blue channel gain control = (1/2+B_GAIN/64)
- [7:4]
-0x08 [ 0 ] Compression mode. 0=No compression, 1=Compression enabled
- [2:1] Maximum scale factor for compression
- [ 3 ] 1 = USB fifo(2K bytes) is full
- [ 4 ] 1 = Digital gain is finish
- [ 5 ] 1 = Exposure is finish
- [7:6] Frame index
-0x09 [7:0] Y sum inside Auto-Exposure area (low-byte)
-0x0A [7:0] Y sum inside Auto-Exposure area (high-byte)
- where Y sum = (R/4 + 5G/16 + B/8) / 32
-0x0B [7:0] Y sum outside Auto-Exposure area (low-byte)
-0x0C [7:0] Y sum outside Auto-Exposure area (high-byte)
- where Y sum = (R/4 + 5G/16 + B/8) / 128
-0x0D [1:0] Audio frame number
- [ 2 ] 1 = Audio is recording
-0x0E [7:0] Audio summation (low-byte)
-0x0F [7:0] Audio summation (high-byte)
-0x10 [7:0] Audio sample count
-0x11 [7:0] Audio peak data in audio frame
-
-The AE area (sx, sy, ex, ey) in the active window can be set by programming the
-registers 0x1c, 0x1d, 0x1e and 0x1f of the SN9C1xx controllers, where one unit
-corresponds to 32 pixels.
-
-[1] The frame headers exported by the SN9C105 and SN9C120 are not described.
-
-
-9. 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 assembling the SN9C1xx PC camera controllers:
-
-Vendor ID Product ID
---------- ----------
-0x0458 0x7025
-0x045e 0x00f5
-0x045e 0x00f7
-0x0471 0x0327
-0x0471 0x0328
-0x0c45 0x6001
-0x0c45 0x6005
-0x0c45 0x6007
-0x0c45 0x6009
-0x0c45 0x600d
-0x0c45 0x6011
-0x0c45 0x6019
-0x0c45 0x6024
-0x0c45 0x6025
-0x0c45 0x6028
-0x0c45 0x6029
-0x0c45 0x602a
-0x0c45 0x602b
-0x0c45 0x602c
-0x0c45 0x602d
-0x0c45 0x602e
-0x0c45 0x6030
-0x0c45 0x603f
-0x0c45 0x6080
-0x0c45 0x6082
-0x0c45 0x6083
-0x0c45 0x6088
-0x0c45 0x608a
-0x0c45 0x608b
-0x0c45 0x608c
-0x0c45 0x608e
-0x0c45 0x608f
-0x0c45 0x60a0
-0x0c45 0x60a2
-0x0c45 0x60a3
-0x0c45 0x60a8
-0x0c45 0x60aa
-0x0c45 0x60ab
-0x0c45 0x60ac
-0x0c45 0x60ae
-0x0c45 0x60af
-0x0c45 0x60b0
-0x0c45 0x60b2
-0x0c45 0x60b3
-0x0c45 0x60b8
-0x0c45 0x60ba
-0x0c45 0x60bb
-0x0c45 0x60bc
-0x0c45 0x60be
-0x0c45 0x60c0
-0x0c45 0x60c2
-0x0c45 0x60c8
-0x0c45 0x60cc
-0x0c45 0x60ea
-0x0c45 0x60ec
-0x0c45 0x60ef
-0x0c45 0x60fa
-0x0c45 0x60fb
-0x0c45 0x60fc
-0x0c45 0x60fe
-0x0c45 0x6102
-0x0c45 0x6108
-0x0c45 0x610f
-0x0c45 0x6130
-0x0c45 0x6138
-0x0c45 0x613a
-0x0c45 0x613b
-0x0c45 0x613c
-0x0c45 0x613e
-
-The list above does not imply that all those devices work with this driver: up
-until now only the ones that assemble the following pairs of SN9C1xx bridges
-and image sensors are supported; kernel messages will always tell you whether
-this is the case (see "Module loading" paragraph):
-
-Image sensor / SN9C1xx bridge | SN9C10[12] SN9C103 SN9C105 SN9C120
--------------------------------------------------------------------------------
-HV7131D Hynix Semiconductor | Yes No No No
-HV7131R Hynix Semiconductor | No Yes Yes Yes
-MI-0343 Micron Technology | Yes No No No
-MI-0360 Micron Technology | No Yes Yes Yes
-OV7630 OmniVision Technologies | Yes Yes Yes Yes
-OV7660 OmniVision Technologies | No No Yes Yes
-PAS106B PixArt Imaging | Yes No No No
-PAS202B PixArt Imaging | Yes Yes No No
-TAS5110C1B Taiwan Advanced Sensor | Yes No No No
-TAS5110D Taiwan Advanced Sensor | Yes No No No
-TAS5130D1B Taiwan Advanced Sensor | Yes No No No
-
-"Yes" means that the pair is supported by the driver, while "No" means that the
-pair does not exist or is not supported by the driver.
-
-Only some of the available control settings of each image sensor are supported
-through the V4L2 interface.
-
-Donations of new models for further testing and support would be much
-appreciated. Non-available hardware will not be supported by the author of this
-driver.
-
-
-10. 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.
-
-Consistently with the hardware limits, this driver also supports image
-downscaling with arbitrary scaling factors from 1, 2 and 4 in both directions.
-However, the V4L2 API specifications don't correctly define how the scaling
-factor can be chosen arbitrarily by the "negotiation" of the "source" and
-"target" rectangles. To work around this flaw, we have added the convention
-that, during the negotiation, whenever the "VIDIOC_S_CROP" ioctl is issued, the
-scaling factor is restored to 1.
-
-This driver supports two different video formats: the first one is the "8-bit
-Sequential Bayer" format and can be used to obtain uncompressed video data
-from the device through the current I/O method, while the second one provides
-either "raw" compressed video data (without frame headers not related to the
-compressed data) or standard JPEG (with frame headers). The compression quality
-may vary from 0 to 1 and can be selected or queried thanks to the
-VIDIOC_S_JPEGCOMP and VIDIOC_G_JPEGCOMP V4L2 ioctl's. For maximum flexibility,
-both the default active video format and the default compression quality
-depend on how the image sensor being used is initialized.
-
-
-11. Video frame formats [1]
-=======================
-The SN9C1xx PC Camera Controllers can send images in two possible video
-formats over the USB: either native "Sequential RGB Bayer" or compressed.
-The compression is used to achieve high frame rates. With regard to the
-SN9C101, SN9C102 and SN9C103, the compression is based on the Huffman encoding
-algorithm described below, while with regard to the SN9C105 and SN9C120 the
-compression is based on the JPEG standard.
-The current video format may be selected or queried from the user application
-by calling the VIDIOC_S_FMT or VIDIOC_G_FMT ioctl's, as described in the V4L2
-API specifications.
-
-The name "Sequential Bayer" indicates the organization of the red, green and
-blue pixels in one video frame. Each pixel is associated with a 8-bit long
-value and is disposed in memory according to the pattern shown below:
-
-B[0] G[1] B[2] G[3] ... B[m-2] G[m-1]
-G[m] R[m+1] G[m+2] R[m+2] ... G[2m-2] R[2m-1]
-...
-... B[(n-1)(m-2)] G[(n-1)(m-1)]
-... G[n(m-2)] R[n(m-1)]
-
-The above matrix also represents the sequential or progressive read-out mode of
-the (n, m) Bayer color filter array used in many CCD or CMOS image sensors.
-
-The Huffman compressed video frame consists of a bitstream that encodes for
-every R, G, or B pixel the difference between the value of the pixel itself and
-some reference pixel value. Pixels are organised in the Bayer pattern and the
-Bayer sub-pixels are tracked individually and alternatingly. For example, in
-the first line values for the B and G1 pixels are alternatingly encoded, while
-in the second line values for the G2 and R pixels are alternatingly encoded.
-
-The pixel reference value is calculated as follows:
-- the 4 top left pixels are encoded in raw uncompressed 8-bit format;
-- the value in the top two rows is the value of the pixel left of the current
- pixel;
-- the value in the left column is the value of the pixel above the current
- pixel;
-- for all other pixels, the reference value is the average of the value of the
- pixel on the left and the value of the pixel above the current pixel;
-- there is one code in the bitstream that specifies the value of a pixel
- directly (in 4-bit resolution);
-- pixel values need to be clamped inside the range [0..255] for proper
- decoding.
-
-The algorithm purely describes the conversion from compressed Bayer code used
-in the SN9C101, SN9C102 and SN9C103 chips to uncompressed Bayer. Additional
-steps are required to convert this to a color image (i.e. a color interpolation
-algorithm).
-
-The following Huffman codes have been found:
-0: +0 (relative to reference pixel value)
-100: +4
-101: -4?
-1110xxxx: set absolute value to xxxx.0000
-1101: +11
-1111: -11
-11001: +20
-110000: -20
-110001: ??? - these codes are apparently not used
-
-[1] The Huffman compression algorithm has been reverse-engineered and
- documented by Bertrik Sikken.
-
-
-12. 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'.
-
-
-13. Credits
-===========
-Many thanks to following persons for their contribute (listed in alphabetical
-order):
-
-- David Anderson for the donation of a webcam;
-- Luca Capello for the donation of a webcam;
-- Philippe Coval for having helped testing the PAS202BCA image sensor;
-- Joao Rodrigo Fuzaro, Joao Limirio, Claudio Filho and Caio Begotti for the
- donation of a webcam;
-- Dennis Heitmann for the donation of a webcam;
-- Jon Hollstrom for the donation of a webcam;
-- Nick McGill for the donation of a webcam;
-- Carlos Eduardo Medaglia Dyonisio, who added the support for the PAS202BCB
- image sensor;
-- Stefano Mozzi, who donated 45 EU;
-- Andrew Pearce for the donation of a webcam;
-- John Pullan for the donation of a webcam;
-- Bertrik Sikken, who reverse-engineered and documented the Huffman compression
- algorithm used in the SN9C101, SN9C102 and SN9C103 controllers and
- implemented the first decoder;
-- Ronny Standke for the donation of a webcam;
-- Mizuno Takafumi for the donation of a webcam;
-- an "anonymous" donator (who didn't want his name to be revealed) for the
- donation of a webcam.
-- an anonymous donator for the donation of four webcams and two boards with ten
- image sensors.