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Old 03-10-2015, 05:28 AM   #1
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In- and Excluding Kernel modules on Beagleboard xM, running Ubuntu

Hi everybody,

I build myself a daughterboard with a CS42448 audiocodec for my BBxM. The CS42448 is supported in the linux Kernel from v3.16 I believe. I build myself a new Kernel of version 3.19.1, where I tried to disable the old audiocodec (twl4030) and enable the driver for the CS42448. Unfortunately this didn't work and if I hit lsmod on the new kernel it only shows TWL4030 audio moduls like

So I tried it the hard way:
I was able to disable the modules for the twl4030 using sudo modprobe -r Modulname. Furthermore I had to disable snd_soc_omap and snd_soc_omap_mcbsp (two packages which pretty sure are required for the CS42448 as well). Now this is the result when I run lsmod:

Module Size Used by
snd_soc_omap_mcbsp 25729 0
snd_soc_omap 2992 1 snd_soc_omap_mcbsp
snd_soc_cs42xx8_i2c 1454 0
snd_soc_cs42xx8 14861 1 snd_soc_cs42xx8_i2c
snd_soc_core 192172 4 snd_soc_omap,snd_soc_cs42xx8,snd_soc_cs42xx8_i2c,snd_soc_omap_mcbsp
snd_compress 13880 1 snd_soc_core
snd_pcm_dmaengine 5770 2 snd_soc_core,snd_soc_omap
snd_pcm 97520 4 snd_soc_core,snd_soc_omap,snd_soc_omap_mcbsp,snd_pcm_dmaengine
snd_timer 22562 1 snd_pcm
snd 70701 4 snd_soc_core,snd_timer,snd_pcm,snd_compress
soundcore 8477 1 snd
leds_pwm 3411 0
w1_smem 898 0
omap_aes 15446 0
omap_hdq 8668 0
wire 34423 2 w1_smem,omap_hdq
smsc95xx 25377 0
twl4030_madc 10557 0
usbnet 35336 1 smsc95xx
evdev 11172 1
pwm_twl_led 4659 1
twl4030_keypad 4518 0
industrialio 51761 1 twl4030_madc
pwm_twl 4560 0
matrix_keymap 2946 1 twl4030_keypad
hsi 11822 0

Then I enabled snd_soc_cs42xx8, snd_soc_cs42xx8-i2c and just to make sure I reenabled snd_soc_omap and snd_soc_omap_mcbsp and tadaaaa nothing happens :/
So my question now is: What can I do now, to "debug" this setup? How can I make the CS42xx8 module take the one of the three i2c-interfaces that I want it to take and check whether the mcbsp (i2s / pcm) interface is used properly? I checked it with an oscilloscope and there is nothing on the i2s as well as the i2c (at least for the desired interface) lines.

Any help would be highly appreciated. I'm quite new to linux and far beyond of knowing what I do and can do

Thank you very much!



Last edited by LittleLenni; 03-10-2015 at 05:29 AM.
Old 03-12-2015, 01:48 PM   #2
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Registered: Feb 2015
Posts: 22

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Hey folks,

any chance anyone has a slight clue what I could check now? Is what I am trying to do allready doomed to fail or do you think there might be a chance to get it to work?

I would be really happy if someone could give me a hand on this!




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