This file defines some DT properties for specific SPI NOR flash features.
The SPI NOR controller drivers may refer to this file, such as fsl-quadspi.txt

Optional properties:
  - spi-nor,ddr-quad-read-dummy: The dummy cycles used by the DDR Quad read.
                                 Please refer to the chip's datasheet. This
                                 property can be 4 or 6 which is less then 8.