[PATCH] Parallel port support for SGI O2

[Arnaud Giersch <arnaud.giersch@free.fr>]

Hello,

I wrote a low-level parallel port driver for the built-in port on SGI
O2 (a.k.a. IP32).

The parallel port is driven by a standard ECP chipset, with
memory-mapped I/O registers.  That's why it was not possible to use
the parport_pc module which assumes port-mapped I/O registers.

What works:
    * Basic modes are supported: PCSPP, PS2.
    * Compatibility mode with FIFO support is present.
    * FIFO can be driven with or without interrupts.

What does not work: 
    * DMA support is not implemented (lack of documentation). If you
      have any information, please tell me.
    * EPP and ECP modes are not implemented (lack of interest). I
      currently do not own any peripheral supporting this extended
      modes. It should not be too difficult to do.

All tests were done with an HP LaserJet 5MP connected to a R5000 SGI
O2.

The module is named parport_ip32.  The patch is not included in this
mail because it is not very small (2383 lines, 73 Kb).  It is however
avalaible from:

  http://arnaud.giersch.free.fr/parport_ip32/parport_ip32-latest.patch.gz

The patch is against the latest Linux/MIPS kernel (2.6.14-rc2 as of
today).  If you prefer that I post it on a mailing list, please just
tell me where, and how (inlined, or gzip'ed attached file).

Further informations are available on:

  http://arnaud.giersch.free.fr/parport_ip32.html

Regards,

        Arnaud Giersch