Pps-gpio overlay?

#1

Has anyone created a pps-gpio overlay to allow the pps-gpio.ko kernel module to use a rock pi gpio pin?

Similar to https://github.com/raspberrypi/linux/blob/rpi-4.4.y/arch/arm/boot/dts/overlays/pps-gpio-overlay.dts for RPI perhaps?

#2

Hey Dave,

I just came across this and I was wondering if you ever found a solution? Iā€™m looking to use PPS for accurate GPS time.

Best

#3

Yes, something like this should work (for GPIO block 2 pin 14).

Or you can just get one of mine prebuilt at https://centerclick.com/ntp/

/dts-v1/;
/plugin/;

/ {
 compatible = "rockchip,rk3308";

 // Enable GPS PPS input pin
 fragment@0 {
  target-path = "/";
  __overlay__ {
   pps: pps {
    compatible = "pps-gpio";
    pinctrl-names = "default";
    pinctrl-0 = <&pps_pins>;
    gpios = <&gpio2 14 0>;
    status = "okay";
   };
  };
 };
 fragment@1 {
  target = <&gpio2>;
  __overlay__ {
   pps_pins: pps_pins {
    rockchip,pins =     <14>;
    rockchip,function = <0>;    // in
    rockchip,pull =     <0>;    // off
   };
  };
 };
};
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