HAL Driver for Raspberry PI GPIOs

Hello,

I am using LinuxCNC directly on a Raspberry Pi 3B+ to control a little robotarm MK2. Because I wasn't able to find a proper driver for the gpios of the Pi, i used this Arduino based solution( github.com/dewy721/EMC-2-Arduino ) to control the stepper motors and servos. But this shows as expected only poor results.
I am currently writting a HAL driver for the gpios of Pi based on the hal_parport.c and the libgpiod. Is libgpiod in this case a good solution or are there faster ways to write and read pins and of better use in case of realtime?

I put the code for free use at github.com/joao404/HAL2PI . At the moment the reset function and inverted datasignals are not finished.

If someone knows a better existing solution or has some notes about my coding it would be nice to get some feedback.

Greetings
Marcel

there are lots of projekts alredy running so you may not need a Haldriver
look on the search field and giv it a try
Raspberry Pi

I myself would love to have something like a hal_pi_gpio in standard distro. Similar to the bb version.
Not for real machine, i'm a pure fan of Mesa, but for playing with Pi4 this would be nice.
Mike

Hi,

I found one project at erste.de/linuxCNC_raspberry_PI4.html (bottom part) which uses WiringPi and a file called hal_gpio.c which you can download from linuxcnc.org.

Marcel

joao404 wrote: If someone knows a better existing solution

If you get version 2.8 / uspace then you should be able to use the hal_pi_gpio component that was recently added.

github.com/LinuxCNC/linuxcnc/commit/e0dc...52586d505f4b9bcda60d

Scroll to the last file on that page to see sample HAL-file usage.

I have made a small tool to calculate the "loadrt hal_pi_gpio dir=... exclude=..."-line. Hope it helps.
Example: hal_pi_gpio-calculator.sh 17:27:22 2:3:4:12:14:15:18
--> loadrt hal_pi_gpio dir=78855 exclude=32394232

Enjoy