Hey @frank-w,
Maybe add this into your wiki?
Getting pps working to a gpio pin.
I have one of these https://learn.adafruit.com/adafruit-ultimate-gps
It has a dedicated pps pin that I previously had working on a Raspberry Pi.
I got it working on the BPI by adding the following to mt7623n-bananapi-bpi-r2.dts
Under the main section:
pps {
pinctrl-names = “default”;
compatible = “pps-gpio”;
gpios = <&pio 72 0>;
status = “okay”;
};
You will need to set CONFIG_PPS=m, CONFIG_PPS_CLIENT_LDISC=m & CONFIG_PPS_CLIENT_GPIO=m in the kernel for GPIO PPS support.
I didn’t need to add anything else to see the pulse on gpio 72 using Debian with kernel 4.9.
Also perhaps a pinmux is needed for other kernels. I’m not sure.
If is is perhaps the following would work (untested):
pps {
pinctrl-names = “default”;
pinctrl-0 = <&pinctrl_pps>;
compatible = “pps-gpio”;
gpios = <&pio 72 0>;
status = “okay”;
};
&pio {
pinctrl_pps: pps@0 {
pins_pps {
pinmux = <MT7623_PIN_72_I2S0_DATA_IN_FUNC_GPIO72>;
};
};
}
mt7623n-bananapi-bpi-r2.dts (19.3 KB)
Can you please test with newer kernel (4.14/4.19)?
what is pps exactly?
Maybe 4.14 as I and using the BPI as a router now and I need it working. 
Here you go: http://mtnstormdaq.com/blog/2012/10/gps-pps-use-as-a-time-reference/
Tested and working under kernel 4.14.
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