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| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt new file mode 100644 index 000000000..f93d51478 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt @@ -0,0 +1,38 @@ +Lantiq SoC External Bus memory mapped GPIO controller + +By attaching hardware latches to the EBU it is possible to create output +only gpios. This driver configures a special memory address, which when +written to outputs 16 bit to the latches. + +The node describing the memory mapped GPIOs needs to be a child of the node +describing the "lantiq,localbus". + +Required properties: +- compatible : Should be "lantiq,gpio-mm-lantiq" +- reg : Address and length of the register set for the device +- #gpio-cells : Should be two. The first cell is the pin number and + the second cell is used to specify optional parameters (currently + unused). +- gpio-controller : Marks the device node as a gpio controller. + +Optional properties: +- lantiq,shadow : The default value that we shall assume as already set on the + shift register cascade. + +Example: + +localbus@0 { + #address-cells = <2>; + #size-cells = <1>; + ranges = <0 0 0x0 0x3ffffff /* addrsel0 */ + 1 0 0x4000000 0x4000010>; /* addsel1 */ + compatible = "lantiq,localbus", "simple-bus"; + + gpio_mm0: gpio@4000000 { + compatible = "lantiq,gpio-mm"; + reg = <1 0x0 0x10>; + gpio-controller; + #gpio-cells = <2>; + lantiq,shadow = <0x77f> + }; +} |