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Diffstat (limited to 'Documentation/powerpc/dts-bindings/spi-bus.txt')
| -rw-r--r-- | Documentation/powerpc/dts-bindings/spi-bus.txt | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/Documentation/powerpc/dts-bindings/spi-bus.txt b/Documentation/powerpc/dts-bindings/spi-bus.txt new file mode 100644 index 00000000000..e782add2e45 --- /dev/null +++ b/Documentation/powerpc/dts-bindings/spi-bus.txt @@ -0,0 +1,57 @@ +SPI (Serial Peripheral Interface) busses + +SPI busses can be described with a node for the SPI master device +and a set of child nodes for each SPI slave on the bus. For this +discussion, it is assumed that the system's SPI controller is in +SPI master mode. This binding does not describe SPI controllers +in slave mode. + +The SPI master node requires the following properties: +- #address-cells - number of cells required to define a chip select + address on the SPI bus. +- #size-cells - should be zero. +- compatible - name of SPI bus controller following generic names + recommended practice. +No other properties are required in the SPI bus node. It is assumed +that a driver for an SPI bus device will understand that it is an SPI bus. +However, the binding does not attempt to define the specific method for +assigning chip select numbers. Since SPI chip select configuration is +flexible and non-standardized, it is left out of this binding with the +assumption that board specific platform code will be used to manage +chip selects. Individual drivers can define additional properties to +support describing the chip select layout. + +SPI slave nodes must be children of the SPI master node and can +contain the following properties. +- reg - (required) chip select address of device. +- compatible - (required) name of SPI device following generic names + recommended practice +- spi-max-frequency - (required) Maximum SPI clocking speed of device in Hz +- spi-cpol - (optional) Empty property indicating device requires + inverse clock polarity (CPOL) mode +- spi-cpha - (optional) Empty property indicating device requires + shifted clock phase (CPHA) mode +- spi-cs-high - (optional) Empty property indicating device requires + chip select active high + +SPI example for an MPC5200 SPI bus: + spi@f00 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "fsl,mpc5200b-spi","fsl,mpc5200-spi"; + reg = <0xf00 0x20>; + interrupts = <2 13 0 2 14 0>; + interrupt-parent = <&mpc5200_pic>; + + ethernet-switch@0 { + compatible = "micrel,ks8995m"; + spi-max-frequency = <1000000>; + reg = <0>; + }; + + codec@1 { + compatible = "ti,tlv320aic26"; + spi-max-frequency = <100000>; + reg = <1>; + }; + }; |