[alsa-devel] Questions about /dev/snd and /proc/asound (new ASoC driver)

Simon Tremblay bidou at videotron.qc.ca
Thu Aug 7 23:03:30 CEST 2008


I have some issues with /dev/snd. First I should explain what I try to do.

I am developing a driver for TLV320AIC23B codec and want to use it on a
AT91RM9200-based board.

I read documentation in sound/soc and created a codec driver
(tlv320aic23b) and a machine driver (for my board). I think it's all I
have to do since AT91 is supported and tlv320aic23b works with i2c and I2S.

When I load my module I obtain that output:

# modprobe snd-soc-armus-tlv320aic23b
ASoC version 0.13.1
AIC23B Audio Codec 0.1
<6>asoc: aic23b <-> at91-ssc1 mapping ok
<6>armus_tlv320aic23b: MCLK rate 12000000Hz
armus_tlv320aic23b: Codec in Master Mode

(I activated debug in soc-core and in my machine driver (based mainly on
eti_b1_wm8731 machine driver)).

I think there is no error here for now...

But there is no /dev/snd created. I don't know for now why... Maybe
someone has an idea?

I think all I have in /proc/asound is correct too:

In /proc/asound I have this listing:

lrwxrwxrwx    1 root     root            5 Jan  1 00:02 ARMUSTLV320AIC2
-> card0
dr-xr-xr-x    4 root     root            0 Jan  1 00:02 card0
-r--r--r--    1 root     root            0 Jan  1 00:02 cards
-r--r--r--    1 root     root            0 Jan  1 00:02 devices
-r--r--r--    1 root     root            0 Jan  1 00:02 modules
-r--r--r--    1 root     root            0 Jan  1 00:02 pcm
-r--r--r--    1 root     root            0 Jan  1 00:02 timers
-r--r--r--    1 root     root            0 Jan  1 00:02 version

cat cards:

 0 [ARMUSTLV320AIC2]: aic23b - ARMUS_TLV320AIC23B
                      ARMUS_TLV320AIC23B (aic23b)

cat devices:

  0: [ 0]   : control
 16: [ 0- 0]: digital audio playback
 24: [ 0- 0]: digital audio capture
 33:        : timer

cat modules:

 0 snd_soc_tlv320aic23b

cat pcm:

00-00: TLV320AIC23B PCM aic23b-PCM-0 :  : playback 1 : capture 1

cat timers:

G0: system timer : 7812.500us (10000000 ticks)
P0-0-0: PCM playback 0-0-0 : SLAVE
P0-0-1: PCM capture 0-0-1 : SLAVE

cat version (of alsa): Advanced Linux Sound Architecture Driver Version
1.0.15 (Tue Nov 20 19:16:42 2007 UTC).

My Linux Kernel version (uname -a): Linux uclibc 2.6.24 #32 PREEMPT Thu
Aug 7 16:20:06 EDT 2008 armv4tl unknown.

When I try to use aplay it doesn't work. I have this error ouput from aplay:

ALSA lib confmisc.c:769:(parse_card) cannot find card ''
ALSA lib conf.c:3510:(_snd_config_evaluate) function
snd_func_card_driver returned error: No such device
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_concat
returned error: No such device
ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer
returned error: No such device
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such device
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM default
aplay: main:545: audio open error: No such device

I think it's because I have nothing in /dev/snd. I'm right?

Thank you,

Simon Tremblay

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