SPI read access to IAM 20680 registers is always returning zero value

Hi all,
I'm working on IAM sensor with SPI mode host interface.
I'm trying to read the PWR_MGMT_ and WHO_AM_I registers.
The SPI read is returning for these registers always i.e) returning the readbuffer data as zero.
As per datasheet, we need to get x for PWR_MGMT_ and xA for WHO_AM_I register.

I'm not getting where could be the problem.

I have attached the files for SPI hardware configuration as well as how the IAM is returning zero by reading through SPI.
The SPI bus is working fine with SPI flash memory with different chipselect. So we feel, there is no issues with SPI bus in the board.

Is this the way of reading the registers correct in the C code?

Regards,
Prabhakar