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Diffstat (limited to 'Documentation/devicetree/bindings/spi/spi-bus.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-bus.txt | 83 |
1 files changed, 1 insertions, 82 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 296015e3c632..e07783505498 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -1,82 +1 @@ -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. -- cs-gpios - (optional) gpios chip select. -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. - -Optional property: -- num-cs : total number of chipselects - -If cs-gpios is used the number of chip select will automatically increased -with max(cs-gpios > hw cs) - -So if for example the controller has 2 CS lines, and the cs-gpios -property looks like this: - -cs-gpios = <&gpio1 0 0> <0> <&gpio1 1 0> <&gpio1 2 0>; - -Then it should be configured so that num_chipselect = 4 with the -following mapping: - -cs0 : &gpio1 0 0 -cs1 : native -cs2 : &gpio1 1 0 -cs3 : &gpio1 2 0 - -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-3wire - (optional) Empty property indicating device requires - 3-wire mode. - -If a gpio chipselect is used for the SPI slave the gpio number will be passed -via the cs_gpio - -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>; - }; - }; +This file has moved to spi-controller.yaml. |
