It might be necessary to emulate CS through a GPIO pin depending on
these 2 conditions:
- the controller's CS pin is not wired, and thus a GPIO pin is the only
option
- The controller is unstable at a certain frequency and cannot set/unset
CS reliably. This is actually a possible issue on DesignWare's SPI
controller in Quark SE or Quarks D2000 where it has been found
unstable at 1Mhz and above.
Change-Id: Ib6a06577906c005ddd347070d476a367a9c3da8a
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
3ef1517c1a