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imx6q SSI help

Question asked by Angelo Dureghello on Feb 29, 2016
Latest reply on Mar 4, 2016 by Angelo Dureghello

Hi all,

 

need some help with linux / SSI interface on imx6q (similar sabreauto board), i am on kernel 3.14 from freescale.

In particular, i have an audio source (FM radio chip) connected to the cpu (i2s, cpu is master).

Datasheet of the radio chip asks to be sure that SSI bitclock is enabled already before enabling his

digital output is enabled. At the same, digital output of the radio chip must be stopped "before" the bitclock is stopped.

So i am trying to be in spec, because this chip someway hangs and doesn't respond in any way to i2c, and this, from datasheet, seems to be due to a non-synchronized digital output enabling.

 

I could delay the digital output enable, with a work launched from the snd_soc_dai_ops .startup callback.

Then, i cannot disable digital output before the stop of the ssi bitclock (fsl_ssi.c). In whatever point of fsl_ssi.c or snd_soc_dai_ops callbacks i try, i an always after the bitclock stop.

 

Every hint is appreciated.

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