Hi Peter,

Thanks for you suggestions.

Regards, Shariff

On Mon, Jan 25, 2010 at 1:44 PM, Peter Ujfalusi peter.ujfalusi@nokia.comwrote:

Hello,

Let's put alsa-devel back to the CC...

On Monday 25 January 2010 09:32:45 ext shariff wrote:

...

Hi Peter,

1. As we only have one Main MIC when I am recording in stereo mode by

specifying "-c 2", one channel is silent and one channel is recorded properly.

As it should. Just as a sidenote, I'm usually using -f dat for the format, which gives 48KHz, stereo 16LE

...

2. But still the recorded channel is noisy, how can I reduce the noise of

the recorded channel?

Hmm, what kind of noise? How are you configuring the dai with the snd_soc_dai_set_fmt? For stereo it should be (if OMAP is slave, TWL is master): SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBM_CFM;

For TDM mode (four channel): SND_SOC_DAIFMT_DSP_A | SND_SOC_DAIFMT_IB_NF | SND_SOC_DAIFMT_CBM_CFM;

See omap3beagle.c how it is done.

...

I have one more question. ( Regarding Audio path)

---> If I want to avoid that one channel silent, do I need to connect

"SUB

...

MIC or AUXR"?( as these are connected right ADC).

If you want audio data there, than yes you need another mic for the right channel.

...

----> If I need to record 4 channel audio without any silent channel do I need to connect digital microphones also?

You can duplicate the channel 1 and 3 to channel 2 and 4, meaning that you route the ADCL and ADCR to these channels (TX1 and TX2 path are both analog). You can also hook up a stereo digital mic to the digimic1 interface, but remember, that the digimic needs 48KHz sampling rate.

-- Péter

...

Regards, Shariff

On Fri, Jan 22, 2010 at 6:29 PM, shariff <shariffsinbox@gmail.commailto:shariffsinbox@gmail.com> wrote: Hi

Peter,

...

Thank you very much for your suggestions.

Regards, Shariff

On Fri, Jan 22, 2010 at 6:11 PM, Peter Ujfalusi <peter.ujfalusi@nokia.commailto:peter.ujfalusi@nokia.com> wrote:

Hello,

...

On Friday 22 January 2010 11:57:23 ext shariff wrote:

...

Hi all,

    I am working with OMAP3 based custom board that has twl4030

codec

...

...

& using linux-2.6.29 kernel from opensource.

This is kind of old...

...

    I have some queries regarding Audio recording.

   Audio codec is connected to twl4030 as bellow

                              TWL4030

                         |--------------------|
                         |
                         |                    |------ MAINMIC

  McBSP2  ------  |i2s/tdm         |

                         | ___________|

  --> One Analog MIC is connected to Main Mic and I am using Audio

path not the Voice path.

       After selecting Main Mic through amixer control.

       and recording audio using "arecord -c 1 -r 8000 -f S16_LE -t

wav -d 20 record-file.wav"

The hardware should have been opened in stereo mode, since it is not supporting the mono, you can verify it by appending -v to arecord and

see

...

how the HW has been opened at the end.

...

   --> Here record is successful but with lot of noise.

      1) Can we record Mono(1 channel) through I2S from TWL4030

codec?

The TWL codec "Audio" path is either stereo or 4 channel. You need to record stereo/4 channel, and than extract/use the data from

the

...

valid channel. In case of Main mic it is the left channel, or Channel 1 or/and 2 (depending on the routings) in four channel mode.

...

      2) To record stereo(2 channels), do we need two Mic's ? (i.e

do

...

...

I need Sub Mic also).

No you don't need. The right channel will not contain valid data (most likely it is going to be silent).

You need to enable the Mic bias 1 for the main mic in your machine

driver,

...

if you have not done that yet:

static const struct snd_soc_dapm_widget your_widgets[] = { ... SND_SOC_DAPM_MIC("Your Mic", NULL), ... };

static const struct snd_soc_dapm_route your_audio_map[] = { ... {"MAINMIC", NULL, "Mic Bias 1"}, {"Mic Bias 1", NULL, "Your Mic"}, ... };

I'm not sure about the state of the twl soc codec driver in 2.6.29, but

my

...

guess is that it should work.

Are there any capture routing option for TX1 path, which selects between Analog and Digimic0? If there is than that has to be set to analog as well.

...

Regards, Shariff

-- Péter