Callback on interupt and adc

[nickehallgren]

Hi!

Maybe I'm missing something but I've been using libmraa (on 4.4 kernel) but since I now want to use 5.x I'm looking for a replacement. Your project looks nice but I have a few questions, in mraa I used a callback for an interrupt like this:

import mraa
import time

def callback(userdata):
    print ("interrupt triggered with userdata=", userdata)

pin = mraa.Gpio(23)
pin.dir(mraa.DIR_IN)
pin.isr(mraa.EDGE_BOTH, callback, None)

while(True):
    time.sleep(5)
    print("5s loop")
    # simply wait for interrupt

but if I understand correctly I now need to poll in the while loop, correct?

import sys, time
from periphery import GPIO

gpio_in = GPIO("/dev/gpiochip1", 24, "in", edge="both")

try:
  while True:
    if gpio_in.poll(0.1):
      print(gpio_in.read_event())
except KeyboardInterrupt:
  gpio_in.close()
  sys.exit(130)

I also need to read the ADC pin (Rock Pi S), is that something you might implement in the future?

Thanks for your great work!

[vsergeev]

Yeah, you can certainly poll it like that. If your program ends up using an event loop to service multiple inputs, you can use the GPIO's underlying file descriptor (gpio_in.fd) with one of the facilities in select, e.g. epoll() or poll(), or in an asyncio environment with loop.add_reader(). Just remember to consume the event with gpio_in.read_event() after the GPIO file descriptor fires.

ADC support would probably come from sysfs IIO, issue #19.

[vsergeev]

Closing this one for now. Let me know if you have any other questions. ADC support / sysfs IIO discussion can continue in #19.