topic Re: Custom SAI Linux Driver Programming in i.MX Processors

Custom SAI Linux Driver Programming

ATAineri — Sun, 27 Oct 2019 13:01:40 GMT

I have iMX6ul to create digital audio player (DAP in future). Many time I created DAP with STM32 and AVR, but never with linux on board. I create device tree for my custom board and now have to write audio driver to work with Burr Brown DSD1794A DAC. It is very easy i2c programmable DAC. I tried to write driver like wm8962.c on my evk board but was confused of its hardness.

Such things with fsl_sai.c. There is a lot of code with no useful comments and I can't understand how to initialize sai for correct working with my DAC.

I understand how to programming dac with i2c on linux but can't understand how to play/pause audio stream and how is it working. How to write driver...

When people use some linux players like CMUS or MOC they can play, pause, rewind etc.

Even if I understand how to programming my dac, I can't understand how to write such driver to work correct with any Linux players like CMUS.

How to write such an audio driver so that sound in Linux works well with any player or system sound? At least run me into a correct thought or related literature. I have only 1 week remain to do it...

Re: Custom SAI Linux Driver Programming

ATAineri — Sun, 27 Oct 2019 13:56:54 GMT

Sorry for my poor English. I want to say that, another word, I have to write common Linux sound system compatible driver.

Re: Custom SAI Linux Driver Programming

igorpadykov — Mon, 28 Oct 2019 06:16:07 GMT

Hi Vladislav

one can start with sect.7.1 Advanced Linux Sound Architecture (ALSA) System on a
Chip (ASoC) Sound attached Linux Manual and alsa documentation

Writing an ALSA Driver — The Linux Kernel documentation

https://www.ibr.cs.tu-bs.de/theses/kurtisi/NMP-EmbeddedClient/Abgabe/Quellen/writing-an-alsa-driver.pdf

Best regards
igor
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