/Documentation/powerpc/dts-bindings/gpio/gpio.txt

 1Specifying GPIO information for devices
 2============================================
 3
 41) gpios property
 5-----------------
 6
 7Nodes that makes use of GPIOs should define them using `gpios' property,
 8format of which is: <&gpio-controller1-phandle gpio1-specifier
 9		     &gpio-controller2-phandle gpio2-specifier
10		     0 /* holes are permitted, means no GPIO 3 */
11		     &gpio-controller4-phandle gpio4-specifier
12		     ...>;
13
14Note that gpio-specifier length is controller dependent.
15
16gpio-specifier may encode: bank, pin position inside the bank,
17whether pin is open-drain and whether pin is logically inverted.
18
19Example of the node using GPIOs:
20
21	node {
22		gpios = <&qe_pio_e 18 0>;
23	};
24
25In this example gpio-specifier is "18 0" and encodes GPIO pin number,
26and empty GPIO flags as accepted by the "qe_pio_e" gpio-controller.
27
282) gpio-controller nodes
29------------------------
30
31Every GPIO controller node must have #gpio-cells property defined,
32this information will be used to translate gpio-specifiers.
33
34Example of two SOC GPIO banks defined as gpio-controller nodes:
35
36	qe_pio_a: gpio-controller@1400 {
37		#gpio-cells = <2>;
38		compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank";
39		reg = <0x1400 0x18>;
40		gpio-controller;
41	};
42
43	qe_pio_e: gpio-controller@1460 {
44		#gpio-cells = <2>;
45		compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
46		reg = <0x1460 0x18>;
47		gpio-controller;
48	};
49
50