0001 Lantiq SoC External Bus memory mapped GPIO controller
0002
0003 By attaching hardware latches to the EBU it is possible to create output
0004 only gpios. This driver configures a special memory address, which when
0005 written to outputs 16 bit to the latches.
0006
0007 The node describing the memory mapped GPIOs needs to be a child of the node
0008 describing the "lantiq,localbus".
0009
0010 Required properties:
0011 - compatible : Should be "lantiq,gpio-mm-lantiq"
0012 - reg : Address and length of the register set for the device
0013 - #gpio-cells : Should be two. The first cell is the pin number and
0014 the second cell is used to specify optional parameters (currently
0015 unused).
0016 - gpio-controller : Marks the device node as a gpio controller.
0017
0018 Optional properties:
0019 - lantiq,shadow : The default value that we shall assume as already set on the
0020 shift register cascade.
0021
0022 Example:
0023
0024 localbus@0 {
0025 #address-cells = <2>;
0026 #size-cells = <1>;
0027 ranges = <0 0 0x0 0x3ffffff /* addrsel0 */
0028 1 0 0x4000000 0x4000010>; /* addsel1 */
0029 compatible = "lantiq,localbus", "simple-bus";
0030
0031 gpio_mm0: gpio@4000000 {
0032 compatible = "lantiq,gpio-mm";
0033 reg = <1 0x0 0x10>;
0034 gpio-controller;
0035 #gpio-cells = <2>;
0036 lantiq,shadow = <0x77f>
0037 };
0038 }
