Adau1761 Kernel Update not working

Hello, I'm having some problems with the ADAU1761
I've been successfully using this codec on kernel 4.1.15, and a specific machine driver (attached you can find the relevant part of the device tree and the machine driver itself).
Then I tried to update the operating system to kernel 4.14.78: with the same exact device drivers, the codec was not working correctly (seems that something is changed in the kernel, regarding the SAI port, or SOC-CORE...).

After a bit of tinkering, I got it working correctly (i had to specify tdm-slot properties in the device tree, and put the codec as the master device).
Then i went to use the same configuration ("simple-audio-card" bindings, codec as master) on the 4.1.15 kernel and its' not working correctly. As you can see from the images, a simple "speaker-test" shows that something is wrong in the way the SOM is outputting his data on the SAI port.
Can you help me? Am i missing something in the device tree? What's changed from kernel 4.1.15 to 4.14.78 regarding the Audio/SAI part?

In the attachments you can find the device tree, the codec device drivers used, the machine driver (zed-adau) and a small video showing waveforms captured with a scope:
ImageA is a "speaker-test" on Kernel 4.1.15, with specific machine driver, codec as slave.
ImageB is a "speaker-test" on Kernel 4.1.15, with simple-audio-card binding, codec as master.
ImageC is a "speaker-test" on Kernel 4.14.78, with simple-audio-card binding, codec as