linux/Documentation/devicetree/bindings/spi/spi_oc_tiny.txt
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   1OpenCores tiny SPI
   2
   3Required properties:
   4- compatible : should be "opencores,tiny-spi-rtlsvn2".
   5- gpios : should specify GPIOs used for chipselect.
   6Optional properties:
   7- clock-frequency : input clock frequency to the core.
   8- baud-width: width, in bits, of the programmable divider used to scale
   9        the input clock to SCLK.
  10
  11The clock-frequency and baud-width properties are needed only if the divider
  12is programmable. They are not needed if the divider is fixed.
  13