BBGW/balenaOS Unable to Setup GPIO

[crbn60]

This appears similar to a variety of issues I see where the library is unable to locate the subsystem, at least that's my interpretation. Running as root using the library installed from master:

# python -c "import Adafruit_BBIO.ADC as ADC; ADC.setup();"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
RuntimeError: Unable to setup ADC system. Possible causes are: 
  - A cape with a conflicting pin mapping is loaded 
  - A device tree object is loaded that uses the same name for a fragment: helper

I'm running a Beaglebone Green Wireless with balenaOS on top of it. In lieu of the version script:

# python -VVV
Python 3.8.2 (default, Apr 27 2020, 19:06:36) 
[GCC 6.3.0 20170516]
# uname -a
Linux 1c72c55 4.14.53+ #1 SMP PREEMPT Mon Mar 9 08:28:48 UTC 2020 armv7l GNU/Linux

Some excerpts from dimes:

[    0.193535] OMAP GPIO hardware version 0.1
[    0.244209] omap_i2c 44e0b000.i2c: could not find pctldev for node /ocp/l4_wkup@44c00000/scm@210000/pinmux@800/pinmux_i2c0_pins, deferring probe
[    0.245647] omap_i2c 4819c000.i2c: bus 2 rev0.11 at 100 kHz
[    0.528596] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
[    0.529724] gpio-of-helper ocp:cape-universal: ready
[    0.532244] wkup_m3_ipc 44e11324.wkup_m3_ipc: could not get rproc handle
[    0.533842] omap_uart 44e09000.serial: no wakeirq for uart0
[    0.534080] 44e09000.serial: ttyO0 at MMIO 0x44e09000 (irq = 30, base_baud = 3000000) is a OMAP UART0
[    1.312619] random: fast init done
[    1.331649] console [ttyO0] enabled
[    1.336218] omap_uart 481a6000.serial: no wakeirq for uart3
[    1.342296] 481a6000.serial: ttyO3 at MMIO 0x481a6000 (irq = 31, base_baud = 3000000) is a OMAP UART3
[    1.353912] omap_rng 48310000.rng: Random Number Generator ver. 20
[    1.422841] CAN device driver interface
[    1.547984] omap_rtc 44e3e000.rtc: registered as rtc0
[    1.554437] i2c /dev entries driver
[    1.560946] omap_wdt: OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec
[    1.568670] softdog: initialized. soft_noboot=0 soft_margin=60 sec soft_panic=0 (nowayout=0)
[    1.578726] cpuidle: enable-method property 'ti,am3352' found operations
[    2.077153] input: tps65217_pwr_but as /devices/platform/ocp/44e0b000.i2c/i2c-0/0-0024/tps65217-pwrbutton/input/input0
[    2.089050] tps65217 0-0024: TPS65217 ID 0xe version 1.2
[    2.095148] at24 0-0050: 32768 byte 24c256 EEPROM, writable, 1 bytes/write
[    2.102608] omap_i2c 44e0b000.i2c: bus 0 rev0.11 at 400 kHz
[    2.158993] bone_capemgr bone_capemgr: Baseboard: 'A335BNLT,GW1A,BBGW19010513'
[    2.159018] bone_capemgr bone_capemgr: compatible-baseboard=ti,beaglebone-black - #slots=4
[    2.181058] hub 1-1:1.0: 4 ports detected
[    2.185292] bone_capemgr bone_capemgr: slot #0: No cape found
[    2.211362] bone_capemgr bone_capemgr: slot #1: No cape found
[    2.244588] bone_capemgr bone_capemgr: slot #2: No cape found
[    2.276128] bone_capemgr bone_capemgr: slot #3: No cape found
[    2.282231] bone_capemgr bone_capemgr: initialized OK.
[    2.294767] omap_rtc 44e3e000.rtc: setting system clock to 2000-01-01 00:00:01 UTC (946684801)

Then, after trying to run ADC.setup(), this gets output:

[  167.687059] bone_capemgr bone_capemgr: part_number 'BB-ADC', version 'N/A'
[  167.700889] bone_capemgr bone_capemgr: slot #4: override
[  167.716845] bone_capemgr bone_capemgr: Using override eeprom data at slot 4
[  167.732783] bone_capemgr bone_capemgr: slot #4: 'Override Board Name,00A0,Override Manuf,BB-ADC'

What else can I determine from the system?

Thank you,

A.

[RobertCNelson]

Awesome! balenaOS are still using kernel overlays! We gave up on that for beagleboard.org, it's too un-reliable, supporting kernel overlays just ends up being a waste of developer resources...

After the overlay loads, do you get the iio adc driver on that system?

debian@bbb-pwr01-ser09:~$ ls -lha /sys/bus/iio/devices/
total 0
drwxr-xr-x 2 root root 0 May 12 03:01 .
drwxr-xr-x 4 root root 0 May 11 17:23 ..
lrwxrwxrwx 1 root root 0 May 11 17:23 iio:device0 -> ../../../devices/platform/ocp/44e0d000.tscadc/44e0d000.tscadc:adc.0.auto/iio:device0

Regards,

[crbn60]

# ls -lha /sys/bus/iio/devices/
total 0
drwxr-xr-x 2 root root 0 May 12 02:48 .
drwxr-xr-x 4 root root 0 May 12 02:48 ..

Doesn't look promising.

[crbn60]

Some more digging makes me thing that my issue is most likely system level and not with the Python library.

What can I do to verify the system setup, before further troubleshooting at a higher level?

This page indicates that further setup is required:

https://www.balena.io/docs/reference/OS/advanced/#setting-device-tree-overlays-dtoverlay-and-parameters-dtparam

[crbn60]

I added the following directly to the /mnt/boot/uEnv.txt file on my development device:

enable_uboot_overlays=1
disable_uboot_overlay_video=1

And ADC.setup() now succeeds. On to the next challenge.

Thanks for your help.