spi-fsl-spi.c with kernel 4.14.70 questions

[Kimmo Saarela <kimmo.saarela@xxxxxxxxx>]

I have two questions related to this driver that is used with the
mpc83xx family of processors. It is bit dated HW platform and hard to
find anyone who would have worked on this matter, that is why I'm asking
these questions here.
1) In the generic SPI driver documentation, it has been stated that
   a drivers setup method should not touch the HW because there might
   be ongoing transfer with the same master, but with another CS line.
   This driver _seems_ to touch the HW by eventually calling
   fsl_spi_change_mode function. Should this be fixed and if so, is here
   anyone who has been working on this driver?

2) This same spi driver uses only the CPU mode or cpu-qe mode of
   operation. On some hardware (mpc8321) it could be possible to use the
   QE engine for the transfers to improve performance. In other quicc
   SoC's there is better support for this. Has someone tested that mode
   of operation with Linux and noticed that it can't be done (some
   limitation on QE with other peripherals?) or is it like it is only
   because there hasn't been any demand for better driver.