1Lantiq SoC External Bus memory mapped GPIO controller
2
3By attaching hardware latches to the EBU it is possible to create output
4only gpios. This driver configures a special memory address, which when
5written to outputs 16 bit to the latches.
6
7The node describing the memory mapped GPIOs needs to be a child of the node
8describing the "lantiq,localbus".
9
10Required properties:
11- compatible : Should be "lantiq,gpio-mm-lantiq"
12- reg : Address and length of the register set for the device
13- #gpio-cells : Should be two.  The first cell is the pin number and
14  the second cell is used to specify optional parameters (currently
15  unused).
16- gpio-controller : Marks the device node as a gpio controller.
17
18Optional properties:
19- lantiq,shadow : The default value that we shall assume as already set on the
20  shift register cascade.
21
22Example:
23
24localbus@0 {
25	#address-cells = <2>;
26	#size-cells = <1>;
27	ranges = <0 0 0x0 0x3ffffff /* addrsel0 */
28		1 0 0x4000000 0x4000010>; /* addsel1 */
29	compatible = "lantiq,localbus", "simple-bus";
30
31	gpio_mm0: gpio@4000000 {
32		compatible = "lantiq,gpio-mm";
33		reg = <1 0x0 0x10>;
34		gpio-controller;
35		#gpio-cells = <2>;
36		lantiq,shadow = <0x77f>
37	};
38}
39