[PATCH] USB: Add ET61X[12]51 Video4Linux2 driver

                       ET61X[12]51 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. Contact information

1. Copyright

============

Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>

2. Disclaimer

=============

Etoms is a trademark of Etoms Electronics Corp.

This software is not developed or sponsored by Etoms Electronics.

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 ET61X151

or ET61X251 PC Camera Controllers.

It's worth to note that Etoms Electronics has never collaborated with the

author during the development of this project; despite several requests,

Etoms Electronics also refused to release enough detailed specifications of

the video compression engine.

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 ET61X[12]51 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 any window resolutions and optional panning within the maximum

  pixel area of image sensor;

- image downscaling with arbitrary scaling factors from 1 and 2 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"

  paragraph);

- full support for the capabilities of every possible image sensors that can

  be connected to the ET61X[12]51 bridges, including, for istance, red, green,

  blue and global gain adjustments and exposure control (see "Supported

  devices" paragraph for details);

- use of default color settings for sunlight conditions;

- dynamic I/O interface for both ET61X[12]51 and image sensor control (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

And finally:

	# USB Multimedia devices

	#

	CONFIG_USB_ET61X251=m

6. Module loading

=================

To use the driver, it is necessary to load the "et61x251" 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 et61x251

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:           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. Optional device control through "sysfs"

==========================================

If the kernel has been compiled with the CONFIG_VIDEO_ADV_DEBUG option enabled,

it is possible to read and write both the ET61X[12]51 and the image sensor

registers by using the "sysfs" filesystem interface.

There are four files in the /sys/class/video4linux/videoX directory for each

registered camera: "reg", "val", "i2c_reg" and "i2c_val". The first two files

control the ET61X[12]51 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, unless you know what you

are doing. 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 if the sensor registers can not be read, "cat" will fail.

To avoid race conditions, all the I/O accesses to the files are serialized.

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 mounting the ET61X[12]51 PC camera controllers:

Vendor ID  Product ID

---------  ----------

0x102c     0x6151

0x102c     0x6251

0x102c     0x6253

0x102c     0x6254

0x102c     0x6255

0x102c     0x6256

0x102c     0x6257

0x102c     0x6258

0x102c     0x6259

0x102c     0x625a

0x102c     0x625b

0x102c     0x625c

0x102c     0x625d

0x102c     0x625e

0x102c     0x625f

0x102c     0x6260

0x102c     0x6261

0x102c     0x6262

0x102c     0x6263

0x102c     0x6264

0x102c     0x6265

0x102c     0x6266

0x102c     0x6267

0x102c     0x6268

0x102c     0x6269

The following image sensors are supported:

Model       Manufacturer

-----       ------------

TAS5130D1B  Taiwan Advanced Sensor Corporation

All the available control settings of each image sensor are supported through

the V4L2 interface.

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 and 2 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

"raw" compressed video data (without frame headers not related to the

compressed data). The current 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.

11. 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'.

L:	linux-usb-devel@lists.sourceforge.net

S:	Maintained

USB ET61X[12]51 DRIVER

P:	Luca Risolia

M:	luca.risolia@studio.unibo.it

L:	linux-usb-devel@lists.sourceforge.net

L:	video4linux-list@redhat.com

W:	http://www.linux-projects.org

S:	Maintained

USB HID/HIDBP DRIVERS

P:	Vojtech Pavlik

M:	vojtech@suse.cz

P:	Luca Risolia

M:	luca.risolia@studio.unibo.it

L:	linux-usb-devel@lists.sourceforge.net

L:	video4linux-list@redhat.com

W:	http://www.linux-projects.org

S:	Maintained

P:	Luca Risolia

M:	luca.risolia@studio.unibo.it

L:	linux-usb-devel@lists.sourceforge.net

L:	video4linux-list@redhat.com

W:	http://www.linux-projects.org

S:	Maintained

obj-$(CONFIG_USB_DABUSB)	+= media/

obj-$(CONFIG_USB_DSBR)		+= media/

obj-$(CONFIG_USB_ET61X251)	+= media/

obj-$(CONFIG_USB_IBMCAM)	+= media/

obj-$(CONFIG_USB_KONICAWC)	+= media/

obj-$(CONFIG_USB_OV511)		+= media/

	  To compile this driver as a module, choose M here: the

	  module will be called dsbr100.

config USB_ET61X251

	tristate "USB ET61X[12]51 PC Camera Controller support"

	depends on USB && VIDEO_DEV

	---help---

	  Say Y here if you want support for cameras based on Etoms ET61X151

	  or ET61X251 PC Camera Controllers.

	  See <file:Documentation/usb/et61x251.txt> for more informations.

	  This driver uses the Video For Linux API. You must say Y or M to

	  "Video For Linux" to use this driver.

	  To compile this driver as a module, choose M here: the

	  module will be called et61x251.

config USB_IBMCAM

	tristate "USB IBM (Xirlink) C-it Camera support"

	depends on USB && VIDEO_DEV

	  To compile this driver as a module, choose M here: the

	  module will be called pwc.

#

sn9c102-objs	:= sn9c102_core.o sn9c102_hv7131d.o sn9c102_mi0343.o sn9c102_ov7630.o sn9c102_pas106b.o sn9c102_pas202bcb.o sn9c102_tas5110c1b.o sn9c102_tas5130d1b.o

et61x251-objs	:= et61x251_core.o et61x251_tas5130d1b.o

obj-$(CONFIG_USB_DABUSB)	+= dabusb.o

obj-$(CONFIG_USB_DSBR)		+= dsbr100.o

obj-$(CONFIG_USB_ET61X251)	+= et61x251.o

obj-$(CONFIG_USB_IBMCAM)	+= ibmcam.o usbvideo.o ultracam.o

obj-$(CONFIG_USB_KONICAWC)	+= konicawc.o usbvideo.o

obj-$(CONFIG_USB_OV511)		+= ov511.o