output nothing except DC noise ! about ar9331-i2s-alsa HOT 11 OPEN

Hi mikeliuvia!

I've only tested the driver with the wm8727 codec which I've only faked because I have no real codec to test with. I've chosen this codec because it was the simplest one I've found, there is no control interface so it is easily possible to measure only the i2s signals. Do you have an oscilloscope? If yes I would suggest to take the wm8727 codec for testing and check if the I2S signals are correct. If that is OK you can change the codec to wm8731 maybe it's just a problem with the control interface.

Regards,
Franz

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franz:
what your meaning is you only measure the i2s signals by oscilloscope but not listen to voice by headphone actually ? okay, thanks to share this, I'll try to check i2s signal firstly.

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Hi mikeliuvia!

I've never tested the driver by hearing any audio, because I do not have any codec. I only have the Carambola2 board which doesn't have any codec on board. I only ported this driver to the ar9331 simply because of pure interest in writing an alsa driver. However as alreasy mentioned I've checked its function with my oscilloscope and the signals there seemed to be just fine.

Regards,
Franz

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Hi Franz, I compiled your sources for OpenWRT BarrierBraker (kernel 3.10.49). Running on TL-WR741ND. I am sending data with "aplay" command. Have tried reading /dev/random and /dev/full as raw data (played as 44,1kHz,16bit,stereo). I can see the I2S_CLK signal with oscilloscope on south side of ar9331 (pin A28). But there is no I2S_SD signal on south side (pin A27) except DC noise. Just the same as mikeliuvia described in his post.

My question is: where did you see the I2S_SD signal on your device? South side (pin A27) or east side (pin A52)? I will go through the source code to find out the register config, but I'd like you to confirm please.

BTW my goals with I2S are described in here.

Regards
Jan

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Hi Jan!

The I2S_SD line is configured to GPIO20 (don't know which pin that is on the SOC). I've tested it and it works fine on the carambola2 board.

Regards,
Franz

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Hi Jan,
I port the driver to a real board which has codec wm8960 ,but there is no sound out ,I don't have oscilloscope to see ,about above problem ,have you got correct I2S_SD signal now ?

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Dear friend, sorry. I still cannot produce any DATA. Once I get there, I will report here.
Good luck!
Jan

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Hi Jan,
I tested with a oscilloscope ,it can produced I2S_SD signal ,but there is no sound out maybe it is caused by configuration of the codec.

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Hi fastwave!

OK, just like I've expected it. Most likely it is a problem with the codec configuration.

Regards,
Franz

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Hello fastwave, can you describe what board and which linux kernel do you use?
Congratulations you have "some" data on I2S_SD. In my case I only had I2S_CLK, but not a single "tick" on I2S_SD.

Jan

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Hi Jan，
the hardware designed by HW team ,but it is very similar with tl-wr703n , we use the openwrt AA ,linux kernel is 3.38 . have you register everything to alsa framework ,at lease you can see below information
asoc: wm8960-hifi <-> ath79-i2s mapping ok , wm8960-hifi is your codec. My codec is wm8960.
if it is register success ,when aplay high level application will use DMA buffer to prepare/start/send to data ,and DMA in AR9331 can works . you can add some printk information to see if there is any DMA interrupt occurs .if not ,of course you cannot see I2S_SD signal

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