# Problem exporting and accessing GPIO42

**URL:** <https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309>\
**Category:** Legato Application Framework\
**Created:** [January 10, 2017, 5:05pm UTC](https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309 "2017-01-10T17:05:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![rio99](https://avatars.discourse-cdn.com/v4/letter/r/d78d45/32.png) [@rio99](https://forum.legato.io/u/rio99)\
**Post date:** [January 10, 2017, 5:05pm UTC](https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309/1 "2017-01-10T17:05:16Z")

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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?

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**Author:** ![rio99](https://avatars.discourse-cdn.com/v4/letter/r/d78d45/32.png) [@rio99](https://forum.legato.io/u/rio99)\
**Post date:** [January 20, 2017, 9:41am UTC](https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309/2 "2017-01-20T09:41:45Z")

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

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**Author:** ![dfrey](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.legato.io/dfrey/32/563_2.png) [@dfrey](https://forum.legato.io/u/dfrey)\
**Post date:** [January 26, 2017, 9:46pm UTC](https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309/3 "2017-01-26T21:46:15Z")

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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](http://source.sierrawireless.com/~/media/support_downloads/legato/legato-dist-source_releasenotes.ashx?la=en).

> 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.

> Resolves:LXSWI9X1517-51

The source code is available here: [http://source.sierrawireless.com/resources/legato/legatolinuxdist/](http://source.sierrawireless.com/resources/legato/legatolinuxdist/)

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-[//source.sierrawireless.com/resources/legato/wpfirmwarerelease/](https://source.sierrawireless.com/resources/legato/wpfirmwarerelease/) 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 “:”

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**Author:** ![rio99](https://avatars.discourse-cdn.com/v4/letter/r/d78d45/32.png) [@rio99](https://forum.legato.io/u/rio99)\
**Post date:** [January 27, 2017, 7:09am UTC](https://forum.legato.io/t/problem-exporting-and-accessing-gpio42/2309/4 "2017-01-27T07:09:11Z")

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thank you for clearing this up.