# Audio Codec: driver implementation

**URL:** <https://mangoh.discourse.group/t/audio-codec-driver-implementation/140>\
**Category:** mangOH Green\
**Created:** [July 7, 2016, 4:13am UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140 "2016-07-07T04:13:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![hui\_s](https://avatars.discourse-cdn.com/v4/letter/h/71e660/32.png) [@hui\_s](https://mangoh.discourse.group/u/hui_s)\
**Post date:** [July 7, 2016, 4:13am UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140/1 "2016-07-07T04:13:25Z")

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On mangOH board, WM8944 is used as audio codec to playback audio via PCM data. Here I have some questions:

1. since WM8944 is configured using I2C interface, there must be a driver thing to configure clock rate, sample resolution, data format etc inside the codec. Where can I find the driver code in Legato framework to make le\_audio\_PlayFile() work?

2. if such driver thing exists and our HW design needs a different codec chip, how can I modify/redo the driver under Legato framework?

Thanks!

Hui

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**Author:** ![asyal](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/asyal/32/78_2.png) [@asyal](https://mangoh.discourse.group/u/asyal)\
**Post date:** [July 13, 2016, 6:17pm UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140/2 "2016-07-13T18:17:27Z")

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> [@hui\_s](#):
>
> if such driver thing exists and our HW design needs a different codec chip, how can I modify/redo the driver under Legato framework?

1. WM8944 codec in built into the kernel and is configured at the kernel level.
2. At this moment, you can rebuild Yocto to add driver support for the different codec chip.

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**Author:** ![hui\_s](https://avatars.discourse-cdn.com/v4/letter/h/71e660/32.png) [@hui\_s](https://mangoh.discourse.group/u/hui_s)\
**Post date:** [July 13, 2016, 6:37pm UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140/3 "2016-07-13T18:37:47Z")

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Thanks!

I am not familiar with Yacto. Do you have guideline or instruction on how to rebuild the kernel?

regards

Hui

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**Author:** ![asyal](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/asyal/32/78_2.png) [@asyal](https://mangoh.discourse.group/u/asyal)\
**Post date:** [July 13, 2016, 8:36pm UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140/4 "2016-07-13T20:36:59Z")

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Hi Hui,  
the post below shows you how we built in tree BT module on Yocto:

> [@How to build WL18xx Bluetooth drivers for mangOH](http://mangoh.discourse.group/t/how-to-build-wl18xx-bluetooth-drivers-for-mangoh/138):
>
> Wiki page is here: you can make edits/add comments there and let the people in the forum know,

We plan to release another Wiki page on building drivers out of tree as well.

cheers

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**Author:** ![hui\_s](https://avatars.discourse-cdn.com/v4/letter/h/71e660/32.png) [@hui\_s](https://mangoh.discourse.group/u/hui_s)\
**Post date:** [July 13, 2016, 8:51pm UTC](https://mangoh.discourse.group/t/audio-codec-driver-implementation/140/5 "2016-07-13T20:51:22Z")

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Hi Asyal

Thanks for help!

Hui