diff options
Diffstat (limited to 'Documentation/devicetree/bindings/spi/spi-bus.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-bus.txt | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index d2c33d0f533e..296015e3c632 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -12,6 +12,7 @@ The SPI master node requires the following properties: - #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 @@ -24,6 +25,22 @@ 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. @@ -36,6 +53,11 @@ contain the following properties. 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 { |