i.MX Processors中的主题 How to send the stereo audio sound to mono SPKOUTL?

How to send the stereo audio sound to mono SPKOUTL?

jacklu — Tue, 26 May 2015 10:28:24 GMT

Hi expert,

Our platform (IMX6SL) only use SPKOUTL as mono speaker.

From the WM8962, the codec can mix the DACL & DACR to SPKMIXL, then output to SPKOUTL.

How to control the ALSA widgets?

BTW, is there any document to describe the architecture about the ALSA audio on FSL IMX6SL platform.

I want to study it.

thanks!

BRs,

Jack

Re: How to send the stereo audio sound to mono SPKOUTL?

art — Thu, 28 May 2015 08:33:21 GMT

Yes, the WM8962 codec contains the Digital Mono Mixer circuit that allows to digitally mix a stereo audio data and output the resulting signal to a single speaker output. Please check on the Pages 92 and 111 of the attached document.

Have a great day,
Artur

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Re: How to send the stereo audio sound to mono SPKOUTL?

art — Thu, 28 May 2015 08:46:27 GMT

For more information on the codec control, please refer to the Chapter 29 of the attached document. It also contains some links to the additional documentation on the i.MX6 Linux ALSA drivers.

Also, the custom codec control can be performed through the low-level I2C driver. For more information, please refer to the Chapter 37 of the attached document.

Have a great day,
Artur

Re: How to send the stereo audio sound to mono SPKOUTL?

jacklu — Fri, 29 May 2015 05:42:08 GMT

Hi Artur,

the Digital Mono Mixer circuit seems support only input ADC to output DAC mix.

It is different from stereo audio (it should be digital data from IMX6SL decoder) to mono DAC.

I try these patch in wm8962_hw_params():

	+snd_soc_write(codec, WM8962_SPEAKER_MIXER_3, 0x003F);
	+snd_soc_write(codec, WM8962_SPEAKER_MIXER_1, 0x00B0);
	+snd_soc_write(codec, WM8962_MIXER_ENABLES, 0x0002);
	return 0;

the sound is mixed.

thanks!

Re: How to send the stereo audio sound to mono SPKOUTL?

jacklu — Fri, 29 May 2015 05:50:12 GMT

Hi Artur,

The ALSA architecture is a little different from others such as Qualcomm's.

Could we use tinymix/tinyplay for audio single test?

thanks!

BRs,

Jack

Re: How to send the stereo audio sound to mono SPKOUTL?

art — Fri, 29 May 2015 06:23:33 GMT

tinymix/tinyplay seem not to be included in the Freescale BSP. Only amixer/aplay are available.

Have a great day,
Artur