From: Misbah khan <misbah_khan@engineer.com>
To: linuxppc-embedded@ozlabs.org
Subject: Re: PPC440EPx GPIO control help
Date: Wed, 17 Oct 2007 05:17:26 -0700 (PDT) [thread overview]
Message-ID: <13252501.post@talk.nabble.com> (raw)
In-Reply-To: <1192618194.13993.25.camel@localhost.localdomain>
I Prefer that you write a coustem driver. map the GPIO address (Either make
use of mapped area of GPIO that u may find in the source for comercial
kernel or else map the physical address in the driver and access it ).
---Misbah
Josh Boyer-4 wrote:
>
> On Tue, 2007-10-16 at 23:21 -0700, Jeff Mock wrote:
>> David Hawkins wrote:
>> >> I have a PPC440EPx Sequoia Evaluation board that runs on Linux 2.6.21.
>> >> What I would want to do is to control (write and read values to) its
>> >> GPIO. Perhaps similar to Turbo C's outputb(0x378,0x01) to write and
>> >> inportb(0x378) to read. I read the PPC440EPx manual but I find it
>> >> difficult to understand.
>> >>
>> >> Could anyone show me any tutorial or some sample codes?
>> >
>> > I copied the code below from some test code I wrote for a TS7300
>> > board (uses an ARM EP9302 processor). However, since its user-space
>> > code it should work fine.
>> >
>>
>> I might be a little out of date, but I think you must write your own
>> driver to wiggle the GPIO pins on a 440 processor. I just finished a
>> project using a 440GX with a 2.6.15 kernel (we froze the code about 8
>> months ago).
>>
>> The 440 powerPC core is a 32-bit processor with 36-bit physical
>> addresses. The physical address for the GPIO pins is someplace above
>> 4GB. An mmap() of /dev/mem only lets you map the lower 4GB of the
>> address space, as a result you can't write a user space program on the
>> 440 to wiggle the GPIO pins. (This was true with 2.6.15, I can't speak
>> for later kernels).
>
> This depends on the 440 chip itself. If I recall correctly, the
> 440EP(x) chips don't have I/O above 4GB.
>
> josh
>
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> Linuxppc-embedded@ozlabs.org
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>
>
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View this message in context: http://www.nabble.com/PPC440EPx-GPIO-control-help-tf4638058.html#a13252501
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next prev parent reply other threads:[~2007-10-17 12:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-17 3:29 PPC440EPx GPIO control help Dell Query
2007-10-17 4:15 ` David Hawkins
2007-10-17 6:21 ` Jeff Mock
2007-10-17 10:49 ` Josh Boyer
2007-10-17 12:17 ` Misbah khan [this message]
2007-10-17 20:26 ` Jeff Mock
2007-10-17 20:41 ` Josh Boyer
2007-10-17 16:19 ` David Hawkins
2007-10-18 2:05 ` Dell Query
2007-10-18 2:00 ` Dell Query
2007-10-18 3:22 ` Jeff Mock
-- strict thread matches above, loose matches on Subject: below --
2007-10-17 3:14 Dell Query
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