Re: [gentoo-embedded] writing device drivers howto

[Walter Goossens]

Morgan, Austin D. wrote:
> The book Linux Device Drivers is my favorite reference for this type of
> question.  You can purchase it from anyone who has OReilly books, or
> download it since it is published under Creative Commons.  The newest
> version is 3rd ed.
>
> Austin Morgan
>
>
That's one of my favorite reads...
You can also (ab)use the /proc filesystem for your module. I used this 
quite a lot and it is easier to use when then the /dev filesystem.
You could also use the /sys filesystem but I have no experience with that...
I'm not sure if it's a good design practice to the /proc filesystem a 
lot (There both people encouraging and discouraging it...) but I found 
it a very easy way to talk to userspace!

Anyway find the book here:
http://lwn.net/Kernel/LDD3/
It is usable both as a reference and as a tutorial!

Greetz Walter Goossens
> -----Original Message-----
> From: gentoo-embedded+bounces-1145-AUSTIN.D.MORGAN=saic.com@g.o on
> behalf of andreas.sumper@×××××××××.at
> Sent: Tue 8/22/2006 8:37 AM
> To: gentoo-embedded@l.g.o
> Subject: [gentoo-embedded] writing device drivers howto
>
> Hi list!
>
> This is some sort of offtopic, but I guess this is the best point to ask.
> I have an embedded system running linux. I need to access some special
> registers (e.g. containing the clock cycles, ...) So I managed to write a
> very simple module, which is able to access the registers. But what makes
> me worrying now, is the way, I have to get the data into my user-space
> application. Is there some documentation, concerning writing device
> drivers and accessing them from the user space anywhere? I found some
> documentation, but either I did not understand the part about getting data
> from kernel space into user space, or it was just simply missing.
>
> Maybe anyone here can help me out!
>
> Thanks in advance and kind regards!
>
> Bye,
> Andy
>
>

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