beaglebone python gpio polling

import select, os

PATH = '/sys/class/gpio/gpio47/{0}'
os.system('echo 27 > /sys/kernel/debug/omap_mux/gpmc_ad15')
os.system('echo in > {0}'.format(PATH.format('direction')))
os.system('echo rising > {0}'.format(PATH.format('edge')))
fd = os.open(PATH.format('value'), os.O_RDONLY | os.O_NONBLOCK)
READ_ONLY = select.POLLPRI
poller = select.poll()
poller.register(fd, READ_ONLY)
count = 0
while True:
    events = poller.poll(-1)
    os.lseek(fd, 0, 0)
    if os.read(fd, 2) == '1\n':
        count += 1
    print count