Fastest GPIO Access

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1

Hi,

I am currently working on an embedded project and need fast access on GPIO to control a read/write line for SPI. Now i have my SPIDEV driver working fine and have written a userspace ‘driver’ which uses a combination of SPIDEV and sysfs GPIO. Now, my GPIO toggle for 2 16 bits words is ~140usecs, I would like to get this down a bit and was wondering if there is a faster way to control the sysfs filesystem than using a generic open/write combo?

Any help would be appreciated, I would also like to keep this in userspace if possible. I have read a bit about mmap but it seems that it’s a dodgy place to start exploring with the complexity of the omap chip.

Regards,
Jack.

2

Hi.

Have you tried applying the real time patch to the kernel?

http://processors.wiki.ti.com/index.php/Realtime

I’m actually working on an audio project that also requires fast access to GPIO inputs, but I’m still in the software developing stage, haven’t got to actually work with the BB.

Regards,
Dan

3

Hi Brady,

this is cool. With your permission I would merge the changes back into
the main branch.
Markus