Dear all,
I have created a custom cape around the STA321MP
<http://www.st.com/web/en/catalog/sense_power/FM125/CL935/SC534/PF251500d.d24>
chip from ST Microelectronics. It has 6 MEMS microphones and outputs them
on an I2S bus with 3 data lines. I am trying to use mcasp0 on the boneblack
side to receive the data. I am now to the point where the codec
configuration happens correctly (I can see the i2s signals with a logic
analyzer) and a soundcard is detected. However, when I try to record sound
with arecord, I get the following error:
root@beaglebone:~# arecord -l
> **** List of CAPTURE Hardware Devices ****
> card 0: EVM [STA321MP EVM], device 0: STA321MP sta321mp-audio-0 []
> Subdevices: 1/1
> Subdevice #0: subdevice #0
> root@beaglebone:~# arecord -D hw:0,0 -f S24_LE -c 6 -r 44100 -t wav
> test.wav
> Recording WAVE 'test.wav' : Signed 24 bit Little Endian, Rate 44100 Hz,
> Channels 6
> arecord: pcm_read:1801: read error: Input/output error
>
Let me know provide more details.
- The codec is frame and bit clocks master
- The connection to mcasp0 is the following:
- Bit clock <=> P9_12 (mcasp0_aclkr_mux3)
- Frame sync clock (L/R) <=> P9_27 (mcasp0_fsr)
- Data <=> P9_28 (mcasp0_axr2)
- Data <=> P9_30 (mcasp0_axr0)
- Data <=> P9_25 (mcasp0_axr3)
- I am using kernel 3.14.41 (because 3.8 doesn't have support for mcasp
with >2 channels)
- I am using dtb-builder to add my device to the device tree
All the code I have added to the kernel (codec and machine code) and to the
device tree is on github. Here are the links to the specific changes I have
made.
kernel:
https://github.com/fakufaku/linux/commit/3a6680960412ef0fc3fbcc6f2c0021350039cc92
device tree:
https://github.com/fakufaku/dtb-rebuilder/commit/127dbf3c82c78cc602058308ed72978b170c99a6
It is my first time trying to code audio driver so please be indulgent :) I
have spent a lot of time on this but it seems I am now completely stuck.
I'd really appreciate some help. I'd be happy to provide more
clarifications on anything.
One thing I do not understand is if I need to add mixer bindings. And also
the audio routing (jack vs codec pins, etc).
Thank you in advance!
Robin
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