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> }; }