Problem exporting and accessing GPIO42


Hello, I have problem with GPIO42, I am trying to export GPIO42 such way:
echo 42 > /sys/class/gpio/export
but Legato responds sh: write error: Device or resource busy
I have already configured GPIO42 using AT command AT+WIOCFG=42,16,1,1,0,0,0 but i still receive this error, how can I unlock GPIO42?

GPIO access via Legato application

It looks like GPIO42 is held by the system, is there any way to release it and use it in my app?


This is a known issue that has been fixed in the Linux kernel. I have quoted the relevant section of the Legato Linux source code release notes.

mdm9615: Defer claiming of IRQ GPIO for TI wifi chip refs/changes/40/9440/3

TI’s WL18XX device is not part of any MDM9615 platform; it was
intended that a daughter card with device is added to the MangOH
platform. If the IRQ GPIO for this device is allocated at boot
time, then any other device in slot 0 of MangOH platform wouldn’t
be able to claim it.

Defer allocation of this GPIO until a daughter card in slot 0 is
detected. GPIO will be claimed by a separate MangOH module that
performs this detection.


The source code is available here:

If you are looking for an easier solution than rebuilding the kernel, then you will have to wait until release 13 of the WP firmware is available here: http-// It seems like that could be available in a couple of weeks. Note: I had to intentionally break my previous link because “new users are only allowed to post 2 links in a post”. Just replace the “-” with “:”


thank you for clearing this up.