How to force enable SYNC signal on ESAI0 bus at boot time (in probe)

[samRocknrolla]

I have an A2B transmitter (AD2428) , that connected to ESAI0 on imx8qm.

I need an enabled SYNC signal in ESAI0 for setup A2B via I2C at boot time (probe function of AD24XX driver). 

I looking SYNC signal on oscilloscope when imx8 sending audio data. But at boot time I have no correct configuration of TDM and can't start audio transferring.

Question.

Is it possible to force enable SYNC on ESAI0 at boot time ?

I can set correct frequency of ESAI0 bus in fsl_esai_dai_probe(...)

static int fsl_esai_dai_probe(struct snd_soc_dai *dai)
{
 * * *
    fsl_esai_set_dai_sysclk(dai, ESAI_HCKT_EXTAL, 49152000, 1);
 * * *
}

But misunderstand how to enable output SYNCK pin before TDM configuration.

[JorgeCas]

Hello,

There are no examples on our BSP to keep SYNC signal on ESAI at boot time but, it seems that you should modify the next registers to enable it:

Transmit Control Register (TCR)
Transmit Clock Control Register (TCCR)
Receive Control Register (RCR)
Receive Clock Control Register (RCCR)

Best regards.