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PC Joystick driver v1.0.9
(c) 1997 Vojtech Pavlik <vojtech@atrey.karlin.mff.cuni.cz>
----------------------------------------------------------------------------
1. Intro
~~~~~~~~
The PC Joystick driver for Linux provides support for analog (variable
resistor based) and digital (switch based) joysticks connected via the PC
game port. It can support up to 2 joysticks.
Should you encounter any problems while using the driver, or joysticks
this driver can't make complete use of, I'm very interested in hearing about
them. Bug reports and success stories are also welcome.
2. Usage
~~~~~~~~
If you enable the joystick driver in the kernel configuration, all
connected joysticks should be found automatically. The driver can detect
standard two-axis two-button, and three-axis four-button joysticks only. If
that isn't your case, you can pass the joystick driver the following kernel
command line arguments:
js=0xXX,0xYY
Where XX and YY are bit masks for the two joysticks, with the bits
representing which buttons and axes of the joystick are present:
Bit | Explanation
-----------------
0 | Axis 0
1 | Axis 1
2 | Axis 2
3 | Axis 3
4 | Button 0
5 | Button 1
6 | Button 2
7 | Button 3
Another method of using the driver is loading it as a module. For that,
select `M' for this driver in the kernel configuration and insert the
module:
insmod joystick.o js=0xXX,0xYY
To enable autoloading/-unloading of the joystick module, you have to add
these lines to /etc/conf.modules:
alias char-major-15 joystick
options joystick js=0xXX,0xYY
To enable the user space programs to read the joystick device, you have to
create the device files using mknod (man mknod for more info):
mknod /dev/js0 c 15 0
mknod /dev/js1 c 15 1
3. Calibration
~~~~~~~~~~~~~~
As of version 1.0 the calibration routines used in the joystick driver are
worth using. The idea of calibration is that you have to calibrate the
joystick only once, and then set the calibration at boot-time, thus removing
the need of re-calibrating it in each program that uses it.
For calibration, use the jscal program, contained in the joystick package
which is available at:
ftp://atrey.karlin.mff.cuni.cz/pub/linux/joystick/joystick-1.0.9.tar.gz
4. Programming Interface
~~~~~~~~~~~~~~~~~~~~~~~~
The 1.0 driver uses a new, event based approach to the joystick driver.
Instead of the user program polling for the joystick values, the joystick
driver now reports only any changes of its state. See joystick.h and
jstest.c included in the joystick package for more information. The joystick
device can be used in either blocking or nonblocking mode and supports
select() calls.
For backward compatibility the old interface is still included, but will
be dropped in the future.
5. Credits
~~~~~~~~~~
Thanks to the following authors that contributed to the joystick driver
development:
0.1-0.5 Arthur C. Smith <asmith@cbnewsd.att.com>
0.5 Eyal Lebedinsky <eyal@eyal.emu.id.au>
0.6 Jeff Tranter <tranter@software.mitel.com>
0.7 Carlos Puchol <cpg@cs.utexas.edu>
0.7.1-0.8 Matt Rhoten <mrhoten@oz.net>
0.7.3 Dan Fandrich <dan@fch.wimsey.bc.ca>
0.7.3 Sverker Wilberg <sverkerw@manila.docs.uu.se>
0.8 Hal Maney <maney@norden.com>
0.8 Bernd Schmidt <crux@pool.informatik.rwth-aachen.de>
0.9 Alan Cox <alan@lxorguk.ukuu.org.uk>
0.9.0-1.0.9 Vojtech Pavlik <vojtech@atrey.karlin.mff.cuni.cz>
6. Change Log
~~~~~~~~~~~~~
The current (1.0.x) version was originally based on the 0.7.3 version of
the joystick driver, which caused some inconsistencies in version numbering.
The following log documents all changes done to the driver by the above
contributors:
Version 0.1 Original version
Works but lacks multi-joystick support
Version 0.2 Added multi-joystick support (minor 0 and 1)
Added delay between measuring joystick axis
Added scaling ioctl
Version 0.3 Modified scaling to use ints to prevent kernel
panics 8-)
Version 0.4 Linux 0.99.6 and fixed race condition in js_read.
After looking at a schematic of a joystick card
it became apparent that any write to the joystick
port started ALL the joystick one shots. If the
one that we are reading is short enough and the
first one to be read, the second one will return
bad data if its one shot has not expired when
the joystick port is written for the second time.
Thus solves the mystery delay problem in 0.2!
Version 0.5 Upgraded the driver to the 0.99.9 kernel, added
joystick support to the make config options,
updated the driver to return the buttons as
positive logic, and read both axis at once
and added some new ioctls.
Version 0.6 Made necessary changes to work with 0.99.15
kernel (and hopefully 1.0). Also did some
cleanup: indented code, fixed some typos, wrote
man page, etc ...
Version 0.7 Support for modules
Version 0.7.1 Fix bug in reading button state of js1
Add include so module compiles under recent kernels
Version 0.7.3 Include directives changed for joystick.h
Separated out joystick detection/counting, cleanup
Fix for detection of 3-axis joysticks
Better detection announcement
Added I/O port registration, cleaned up code
Version 0.8 New read loop
Cleaned up #includes to allow #include of joystick.h with
gcc -Wall and from g++
Made js_init fail if it finds zero joysticks
General source/comment cleanup
Use of MOD_(INC|DEC)_USE_COUNT
Changes to compile correctly under 1.3 in kernel or as module
Version 0.9 Ported to 2.1.x
Reformatted to resemble Linux coding standard
Removed semaphore bug (we can dump the lot I think)
Fixed xntp timer adjust during joystick timer0 bug
Changed variable names to lower case. Kept binary compatibility.
Better ioctl names. Kept binary compatibility.
Removed 'save_busy'. Just set busy to 1.
Version 0.9.0 Based on 0.7.3
New read function that allows two axes to have the same value
New joystick calibration code
Real support for 3-axis joysticks
CPU speed independent timeouts
Reads may happen even for unwhole record size => cat /dev/js0 works
Correct error for lseek
/dev/js? can be read simultaneously by several processes
Version 0.9.1 IOCTLs now obey general Linux IOCTL rules ('j' letter assigned)
Use of verify_area result codes
Fuzz correction added
Semaphore and many cli()'s removed
Fix for TurboFire joysticks - read buttons always
Fix for broken joysticks - return with -ENODEV only if joystick
completely disconnected
Fix in read function to allow zero results
Broken line correction added for broken joysticks (eg. JB-500)
Timeouts back separated for easier setting
Some fixes and cleanups in read function
Version 0.9.2 Fixed a typo causing nothing to be working
Version 1.0.0 Event approach started
Version 1.0.1 Complete rewrite
Compiles but doesn't work
Version 1.0.2 Works, many bugs fixed, more yet to come
Version 1.0.3 Tail cutting logic changes & fixes
Fix in js_do_bh - no more zero values for axes
Lost event changes & fixes
Version 1.0.4 Kernel command line & module configuration support
Better cli()/sti() handling
Linux 2.1.25 select => poll changes
Version 1.0.5 Fixes in calibration routines
Better jscal
Version 1.0.6 Backward compatibility with old js driver added
Init value after recalibration bug fixed
Using KERN_* printk() codes
Finally leaving ALPHA and going beta
Cosmetic changes
Version 1.0.7 Readme update
Linux 2.1.89 poll update
Compatibility mode fix - refresh data after open
Cosmetic changes & cleanup
Version 1.0.8 Changing the __u16 data to __s16 in event packet
The range is now -32727..0..32767
Broken line correction needs 2 coefs less
Fix to report number of buttons correctly
Removed various trailing spaces
Version 1.0.9 Fix for compatibility mode - don't do correction
Fix max number of module parameters
7. To do
~~~~~~~~
Sooner or later I'll get to these:
Make an optional read routine using Pentium timers for better precision (*)
Support for hats and more buttons ala CH Flightstick (*)
Support for hats ala TM FCS (*)
Include support for MS SideWinder digital mode (*)
Create patches for most common programs using joystick
Support for cards with HW speed compensation
Support for more than one joystick port
(*) - Already in the development 1.1 version.
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