First I had the same problem as one of the earlier posters, I could not get any writes to take effect. Then I realized writes have to be done with SPI mode 1, reads with SPI mode 0.
But now, I can only seem to write to registers 0x8, 0x9 and 0xa. If I write to reg 8 to a mode other than 2, then do a reset by writing to 0x9, the mode is restored back to 2, the default. This proved that SW reset took place.
I cannot write to regs 0-3 the channel config registers. for example. These are always read back as 0. Same with the other remaining registers like 4, 5, 6.
I have made sure I am in IDLE mode 0 via register 8 as described in the datasheet.