imx6q SSI help

[angelo_d]

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.

[angelo_d]

Hi Victor,

well, system is configured correctly, imx6q is the master, AM/FM radio chip is the slave. Audio works perfect once SSI transfer is established.

Issue i have is that i should have the SSI clock to start "after" the radio fm chip enables his "digital output" feature. And the SSI clock should stop "before" the radio FM chip disable his "digital output" feature. I cannot actually obtain this from linux, since using an asoc codec driver scheme, SSI clock is started before the chip enables his digital output, and SSI clock is stopped before digital output is disabled.

[b36401]

Please note that SSI in i.MX6 can be either a clock master or a clock slave.

So first please make sure that you configured the sides (i.MX and FM ones) right.

Also please "reverse" clock direction.

And also please try to play with polarity.

Have a great day,

Victor

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