1 ARM PL022 SPI controller
4 - compatible : "arm,pl022", "arm,primecell"
5 - reg : Offset and length of the register set for the device
6 - interrupts : Should contain SPI controller interrupt
9 - cs-gpios : should specify GPIOs used for chipselects.
10 The gpios will be referred to as reg = <index> in the SPI child nodes.
11 If unspecified, a single SPI device without a chip select can be used.