Date: Mon, 12 Mar 2018 00:44:57 +0000 From: Shamim Shahriar <shamim.shahriar@gmail.com> To: freebsd-arm@freebsd.org Subject: PPS or /dev/ppsN on Raspberry Pi 3 Message-ID: <819975e8-56a8-677b-e5f5-003ff2091553@gmail.com>
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Good evening everyone.
Objective: get a GPS module work with Raspberry Pi 3 and FreeBSD
v12-CURRENT (it has been indicated on several sites that the earlier
versions of FreeBSD do not play well with Pi3), and get a /dev/pps0 so I
can get the PPS from gpio 18 and time from a usb serial converter.
I have the hardware and they are all plugged in exactly as they should.
if I replace the pi with a Pi-B then it all works exactly as they
should, but with Pi3 it is proving to be more challenging. I had been
trying various things in the Kernel to get the /dev/pps0 (and also
/dev/pps1, which I am enabling in case I get to use another module)
which has not created even once so far.
IAll the documentation I have come across refers to rPi up to model 2,
and nothing on 3. As far as I can gather, I need to put
options PPS_SYNC
in the kernel configuration, which I did. There are also instructions on
adding pps lines to the various dtb files that goes into the /boot/msdos
folder -- but Rasperry Pi3 /does not/ have the /boot/msdos, it has efi,
and my understanding is that the content of the efi is actually pulled
from the github (no source available, only the final binaries to put in
there). I tried to put those on rpi2.dts, didn't work.
here are the relevant lines from the file. Please note, I want to PPS,
one on gpio18 the other on gpio 23/
rpi_ft5406 {
compatible = "rpi,rpi-ft5406";
status = "okay";
};
pps@0 {
compatible = "pps-gpio";
gpios = <&gpio 18 0>;
status = "okay";
};
pps@1 {
compatible = "pps-gpio";
gpios = <&gpio 23 0>;
status = "okay";
};
leds {
compatible = "gpio-leds";
my understanding is, whatever dtb file is being used on RPi3, these are
downloaded from github
(https://github.com/raspberrypi/firmware/tree/master/boot) and there is
no way of modifying them as they are all binary files. Would appreciate
if someone could please confirm that for me.
Would appreciate if someone could please point me to the correct
direction as I seem to be going around very blindly and not seeing the
possible solution to the problem.
Best regards
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