GPIO library leaves LED is a bad state on latest BeagleBone image on PocketBeagle

[erikwelsh]

When running the LED blink code for a USR led on the PocketBeagle with the latest image (bone-debian-9.5-iot-armhf-2018-08-30-4gb.img.xz), the LED is left in a bad state upon exit (i.e. LED looks partially lit). At that point, you are unable to use that LED until you perform a hard reboot of the PocketBeagle. Here is the information to recreate the issue on the PocketBeagle:

debian@beaglebone:/var/lib/cloud9/file_io$ uname -a
Linux beaglebone 4.14.67-ti-r73 #1 SMP PREEMPT Thu Aug 30 00:08:52 UTC 2018 armv7l GNU/Linux

debian@beaglebone:/var/lib/cloud9/file_io$ python
Python 2.7.13 (default, Sep 26 2018, 18:42:22)
[GCC 6.3.0 20170516] on linux2
Type "help", "copyright", "credits" or "license" for more information.

import Adafruit_BBIO.GPIO as GPIO
GPIO.file
'/usr/local/lib/python2.7/dist-packages/Adafruit_BBIO-1.0.10-py2.7-linux-armv7l.egg/Adafruit_BBIO/GPIO.so'
exit()

debian@beaglebone:/var/lib/cloud9/file_io$ cat bbio_led.py
import Adafruit_BBIO.GPIO as GPIO
import time

LED = "USR3"

GPIO.setup(LED, GPIO.OUT)

while True:
GPIO.output(LED, GPIO.HIGH)
time.sleep(0.5)
GPIO.output(LED, GPIO.LOW)
time.sleep(0.5)

The issue is in the gpio_export() function of source/event_gpio.c. If you check that the GPIO is an LED before executing the export commands, like what is done in gpio_set_direction, then this fixes the issue.

I will send a pull request with the fix. This is a quick update that copies the LED detection code from gpio_set_direction. Eventually, the code should be refactored to consolidate the LED detection into a separate function or macro.

Keep up the good work and thanks for all the support that this library provides.

[pdp7]

thanks for creating the PR. I will test this out and merge if no issues.

[pdp7]

I was able to test this successfully on BeagleBone Blue and turn on and off all 4 USR LEDs, in addition to the other built-in LEDs.

import Adafruit_BBIO.GPIO as GPIO
import time

# test built in LEDs on BeagleBone Blue
LED =  [ "USR0" , "USR1", "USR2", "USR3", "RED_LED", "GREEN_LED", "BAT25", "BAT50", "BAT75", "BAT100", "WIFI" ]

for i in LED:
	print("{0}: setup".format(i))
	GPIO.setup(i, GPIO.OUT)

while True:
	for i in LED:
		print("{0}: on".format(i))
		GPIO.output(i, GPIO.HIGH)
		time.sleep(0.5)
		print("{0}: off".format(i))
		GPIO.output(i, GPIO.LOW)
		time.sleep(0.5)

[pdp7]

I have merged #282
thanks @erikwelsh