AD9528: Device tree setting for Reg 0x404 -Sysref_in Receiver control

Hi Analog.

I'm trying to alter the device tree blob so we can boot the Adrv9009W-PCBZ board with our own settings.  We use this evaluation board on top of the ZCU102.

We clearly see from altering the virtual file system we need to set bit 0 of the AD9528 register 0x404  ( Sysref differential receiver control )  in order to get our board working with an external RF LO.

I can't find any device tree property  to do so, but the list found on the AD9528 reference page here seems incomplete.

As an example:  adi,sysref-request-enable can not be found on this page but it occurs in adrv9009.dtsi So I wonder if this could be the case with this register setting?

However when I open the source file, it seems register 0x404 seems not been included in any way to get addressed. Source file 

My question: How do I enable the Sysref differential receiver control bit from within the device tree?

Thanks Analog,