Hi,

I wonder if there is a way of using the GPIO from userland, I mean, without writing a driver.
Can anyone help me with this?

In case you need to know the board i'm using: it's a AT91SAM9261 and the kernel i'm running is ver 2.6.21.

Regards,
Diego A. Fons.

Hi there

I prefer using a driver, since that layers/modularizes the code.

Anyway I did come across this site the other day:
http://www.simtec.co.uk/appnotes/AN0014/
that describes what you are asking.
If you're fuzzy on physical/virtual memory concepts, then this is required reading.

There's also a few threads on this forum on this topic you could search for.

Regards

this is not directly for ARM, but it can aplied.

http://www.avrfreaks.net/wiki/index.php ... 82.6.18%29

Jonathan

If you just want to toggle some gpio or poll the status of a pin, using mmap will get you there. However, if you want to do anything robust, interrupt-driven, etc, you should learn how to write a driver. I did not know how to write drivers two months ago and had to learn on the fly. GPIO is a great intro to doing that. Since the GPIO driver, I have written drivers for the ADC, SSC, TWI (buggy though), and an ALSA-compliant PCM driver. There are people who can help if you do your part and learn the stuff.