Kernel Release Cycle 16

#!/usr/bin/env python3

# 1. Connect motors first!
# 2. Run this program in a terminal
# 3. Control the motors in a second terminal
# 4. Watch the output of this program
# 5. Press CTRL+C to stop this program

import glob
import select

motors = glob.glob('/sys/class/tacho-motor/motor*')
p = select.poll()
lookup = {}

for m in motors:
    # get the output port name for each motor
    with open(m + '/address', 'r') as a:
        name = a.read().strip()

    # get a handle to the status attribute
    s = open(m + '/state', 'r')

    # register the status attribute with the poll object. POLLPRI is important!
    p.register(s, select.POLLPRI)

    # save these for later
    lookup[s.fileno()] = (name, s)

while True:
    # wait for a an event
    for fd, event in p.poll():
        # get the info for the motor that caused the event
        name, s = lookup[fd]

        if event & select.POLLPRI:
            # print info about the event
            s.seek(0)
            print(name, s.read().strip())
        else:
            print(name, 'Poll error!')