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authorGreg Kroah-Hartman <gregkh@suse.de>2011-02-24 11:36:31 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-02-24 11:36:31 -0800
commitf227e08b71b9c273eaa29a57370a3a5b833aa382 (patch)
tree9f1483776a2bde3bb1a6bd744e69acf19f6f3428 /Documentation/devicetree/bindings/spi/spi-bus.txt
parentfec38d1752c01ad72789bac9f1a128f7e933735d (diff)
parentf5412be599602124d2bdd49947b231dd77c0bf99 (diff)
Merge 2.6.38-rc6 into tty-next
This was to resolve a merge issue with drivers/char/Makefile and drivers/tty/serial/68328serial.c Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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+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>;
+ };
+ };