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

   1 Specifying GPIO information for devices
   2 ============================================
   3
   4 1) gpios property
   5 -----------------
   6
   7 Nodes that makes use of GPIOs should define them using `gpios' property,
   8 format 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
  14 Note that gpio-specifier length is controller dependent.
  15
  16 gpio-specifier may encode: bank, pin position inside the bank,
  17 whether pin is open-drain and whether pin is logically inverted.
  18
  19 Example of the node using GPIOs:
  20
  21         node {
  22                 gpios = <&qe_pio_e 18 0>;
  23         };
  24
  25 In this example gpio-specifier is "18 0" and encodes GPIO pin number,
  26 and empty GPIO flags as accepted by the "qe_pio_e" gpio-controller.
  27
  28 2) gpio-controller nodes
  29 ------------------------
  30
  31 Every GPIO controller node must have #gpio-cells property defined,
  32 this information will be used to translate gpio-specifiers.
  33
  34 Example 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