Re: XFree86 elographics_drv.o Correll Touch 5000

In response to myself...

1) There isn't a HOWTO write a XFree86 Driver that I could find.

2) There is samples in the source code, as well as similar drivers
   for touchscreen needs.

What I did was:

get the source code for xserver-xfree86
on debian:
    cd /usr/local/src
    apt-get source xserver-xfree86

then build the source in it's entirety
(so all the libraries and dependencies are build)
    cd /usr/local/src/xfree86-4.3.0.dfsg.1/build-tree/xc-xserver-xfree86-dbg
    make World
    (wait...)

then go find the example driver you want to start hacking up
    cd /usr/local/src/xfree86-4.3.0.dfsg.1/build-tree/xc-xserver-xfree86-dbg/programs/Xserver/hw/xfree86/input/elographics

make a change to the source file to see your code changes work...
    (I would suggest changing something that logs to screen, or the logfile)...
    vi xf86Elo.c
    make
    cp elographics_drv.o /usr/X11R6/lib/modules/input/

make sure you're specifying that driver in XF86Config-4
    Section "InputDevice"
        ...
        Driver     "elographics"
        Option     "Device"          "/dev/ttyS0"
        ...
    EndSection

Start your X server...
    startx

See your change (or see the logging occur).

If that works.
You can now make changes to the source code, and see the changes.

###

NEXT UP: writing your driver for your hardware.

1) Request the Hardware Program manual from the manufacturer.
   (in my case it was ELO that bought out CarrollTouch)

2) Write a simple C script that communicates to the device,
   following the instructions from the Program manual.
   (this was used to quickly debug serial device communication)

3) Incorporate your working C script in the appropriate places
   into your x driver modified above.

4) Possibly change the name of the driver to something
   that resembles your hardware.

5) Submit the code for review, or addition.

###

Which brings me to a question,
HOW DO I submit my code for review or addition?

Thanks!

On Mon, Mar 07, 2005 at 03:31:24PM -0800, todd wrote:
> I have:
>     Correll Touch 5003-0768-01 (Correll Touch was bought out by Elo)
>         -- an infra-red touchscreen wrapper.
>     XFree86 Version 4.3.0.1 (Debian 4.3.0.dfsg.1-10 20041215174925)
> 
> The linux docs for Elo:
>     http://www.elotouch.com/support/linux.asp
>     "Linux drivers for Elo touchscreens are available in the public
>      domain, typically on Linux installation CDs and various FTP
>      sites such as www.xfree86.org. These Linux drivers are compatible
>      with Elo AT4 2215, AccuTouch E271-2210, IntelliTouch E281-2310,
>      IntelliTouch 2500S, and CarrollTouch 4000S controllers."
> 
> The problem:
>     the eloprahics_drv.o spews "Dropping one byte in an attempt to synchronize"
>     when used.
> 
> Troubleshooting done:
>     I have done a "od -h -w10 </dev/ttyS0" from the console,
>     I have not received any characters when screen is touched,
>     but I do see the cursor blinking rapidly, if I unplug the serial cable
>     the blinking slows to regular console blinking pace.
> 
>     I have also plugged in an old serial mouse to /dev/ttyS0 and
>     validated that cat /dev/ttyS0 works fine, so I know the port is /dev/ttyS0.
> 
> TODO (Solution):
>     Write/modify a driver to get this touchscreen working.
> 
> HOW:
>     I haven't seen any documentation on the best practices for writing
>     a XFree86 Driver (or modifying one).
> 
>     Is there a step-by-step "HOWTO write a XFree86 Driver"?
> 
> Thanks!