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[Lcdproc] adding support for ARM machines


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  • From: gfk AT logidac.com (Guillaume Filion)
  • Subject: [Lcdproc] adding support for ARM machines
  • Date: Thu Jan 6 19:58:01 2005

Liberty Young wrote:
> Hello all,

Hi,

> I have an ARM-based board with an attached HD44870 display that I've
> been asked to add support for in lcdproc by a customer. So far, this
> taks seems like it will take longer than I initially thought as
> everything seems I/O port centric; whereas with ARM boards, I/O is done
> away with and everything (typically) is accessed through mmap().
>
> Any tips or hints for me to start looking at? Anything I should be aware
> of before I start putting my node to the grindstone on this?

You might want to take a look at the file port.h in directory
server/drivers/. It's an interface for the low level I/O functions used
by the parallel port.

From the comments of the file:
-----
This file defines 6 static inline functions for port I/O:

static inline int port_in (unsigned short port);
Read a byte from port
Returns the content of the byte.

static inline void port_out (unsigned short port, unsigned char val);
Write a char(byte) 'val' to port.
Returns nothing.

static inline int port_access (unsigned short port);
Get access to a specific port
Returns 0 if successful, -1 if failed

static inline int port_deny (unsigned short port);
Close access to a specific port
Returns 0 if successful, -1 if failed

static inline int port_access_multiple (unsigned short port, unsigned
short count)
Get access multiple to ports at once.
Returns 0 if successful, -1 if failed

static inline int port_deny_multiple (unsigned short port, unsigned
short count)
Close access to multiple ports at once.
Returns 0 if successful, -1 if failed

If you make modifications to this file: References to the LPT port
should not be in this file but in lpt-port.h ...
-----

I don't know enough about these things (mmap(), low level I/O) to be
sure that it will help you, but I hope it will. If you manage to make it
work, please consider sending a patch to this mailing list.

Best,
GFK's
--
Guillaume Filion, ing. jr
Logidac Tech., Beaumont, Québec, Canada - http://logidac.com/
PGP Key and more: http://guillaume.filion.org/




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