[PARPORT] Re:[parport parallel programming]

From: Benavides, Edward A (edward.a.benavides@intel.com)
Date: Mon Apr 03 2000 - 11:24:27 EDT

  • Next message: Levesque, Christopher: "[PARPORT] ppSCSI patch for 2.2.12 kernel"

    I was hoping that this person would post their program so that I can see how
    they talk to the parallel port.
    I am trying to write a device driver that will talk with the parallel port
    so that I can then hook up an emulation device.
    This is to work in ECP mode but for now anything will do. Speed is an issue
    but I cannot change the kernel internals so I have to work with what I have.
    I do not have any experience with writing device drivers so, anyone who has
    a compiled code that works on RH 6.2 kernel 2.2.14 is encouraged to please
    send me some code so that I can try to hook this device up.

    Thank you



    I had a very similar situation. Speed was also a consideration for me.
    parport in 2.2.x doesn't use the hardware epp (or ecp?) handshanks and is
    thus considerably slower. Our "driver" talks to the parallel port
    hardware directly - the "ioperm and inb/outb" solution. To get
    interrupts, we wrote a very simple kernel module - your user program opens
    a device file, and does a read. The read blocks until an interrupt occurs.
    That's about it.

    If that sound useful to you, I could post the kernel module and some
    outline of our driver code.

    We get very good throughput - using 32 bit writes we can output data at a
    1 MB/s using a SIIG parallel pro dual isa card.

    I haven't done any testing of the latentcy between interrupt occuring and
    the return of the user program - that hasn't been very important here.


    > I am new to kernel programming and especially new to parallel programming
    > under Linux. I am wondering if anyone can point me in the direction of
    > information regarding using the parport driver under Linux? Basically
    > I need to do is write a driver for a custom parallel device. It is
    > interrupt driven so I'm told that I must write a kernel based interrupt
    > handler. Since parport seems to provide much of the functions I will use,
    > I'd rather use it than write my own module from the ground up. Is there
    > programming documentation out there or a simple driver I could read to
    > me some clues on where to begin?

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