arch/arm/boot/dts/overlays/rotary-encoder-overlay.dts

   1 // Device tree overlay for GPIO connected rotary encoder.
   2 /dts-v1/;
   3 /plugin/;
   4
   5 / {
   6         compatible = "brcm,bcm2835";
   7
   8         fragment@0 {
   9                 target = <&gpio>;
  10                 __overlay__ {
  11                         rotary_pins: rotary_pins@4 {
  12                                 brcm,pins = <4 17>; /* gpio 4 17 */
  13                                 brcm,function = <0 0>; /* input */
  14                                 brcm,pull = <2 2>; /* pull-up */
  15                         };
  16
  17                 };
  18         };
  19
  20         fragment@1 {
  21                 target-path = "/";
  22                 __overlay__ {
  23                         rotary: rotary@4 {
  24                                 compatible = "rotary-encoder";
  25                                 status = "okay";
  26                                 pinctrl-names = "default";
  27                                 pinctrl-0 = <&rotary_pins>;
  28                                 gpios = <&gpio 4 0>, <&gpio 17 0>;
  29                                 linux,axis = <0>; /* REL_X */
  30                                 rotary-encoder,encoding = "gray";
  31                                 rotary-encoder,steps = <24>; /* 24 default */
  32                                 rotary-encoder,steps-per-period = <1>; /* corresponds to full period mode. See README */
  33                         };
  34                 };
  35
  36         };
  37
  38         __overrides__ {
  39                 pin_a =             <&rotary>,"gpios:4",
  40                                     <&rotary_pins>,"brcm,pins:0",
  41                                     /* modify reg values to allow multiple instantiation */
  42                                     <&rotary>,"reg:0",
  43                                     <&rotary_pins>,"reg:0";
  44                 pin_b =             <&rotary>,"gpios:16",
  45                                     <&rotary_pins>,"brcm,pins:4";
  46                 relative_axis =     <&rotary>,"rotary-encoder,relative-axis?";
  47                 linux_axis =        <&rotary>,"linux,axis:0";
  48                 rollover =          <&rotary>,"rotary-encoder,rollover?";
  49                 steps-per-period =  <&rotary>,"rotary-encoder,steps-per-period:0";
  50                 steps =             <&rotary>,"rotary-encoder,steps:0";
  51                 wakeup =            <&rotary>,"wakeup-source?";
  52                 encoding =          <&rotary>,"rotary-encoder,encoding";
  53                 /* legacy parameters*/
  54                 rotary0_pin_a =     <&rotary>,"gpios:4",
  55                                     <&rotary_pins>,"brcm,pins:0";
  56                 rotary0_pin_b =     <&rotary>,"gpios:16",
  57                                     <&rotary_pins>,"brcm,pins:4";
  58         };
  59 };