Date: Mon, 12 Mar 2018 08:45:35 -0600 From: Ian Lepore <ian@freebsd.org> To: Shamim Shahriar <shamim.shahriar@gmail.com>, Oleksandr Tymoshenko <gonzo@bluezbox.com> Cc: freebsd-arm@freebsd.org Subject: Re: PPS or /dev/ppsN on Raspberry Pi 3 Message-ID: <1520865935.84937.169.camel@freebsd.org> In-Reply-To: <9d27f6ff-d317-aa24-4f22-b06624fd6d1d@gmail.com> References: <819975e8-56a8-677b-e5f5-003ff2091553@gmail.com> <20180312011202.GA60784@bluezbox.com> <9d27f6ff-d317-aa24-4f22-b06624fd6d1d@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 2018-03-12 at 07:38 +0000, Shamim Shahriar wrote:
> On 12/03/2018 01:12, Oleksandr Tymoshenko wrote:
> >
> > sysctl -b hw.fdt.dtb | dtc -I dtb -O dts | grep pps
> Hello Gonzo
>
> I made a little change (pps numbers) on your example and put that in
> place. After reboot, if I run the command above, I can see the two
> pps
> devices
> # sysctl -b hw.fdt.dtb | dtc -I dtb -O dts | grep pps
> pps@1 {
> compatible = "pps-gpio";
> pps@0 {
> compatible = "pps-gpio";
>
> However, there is no /dev/pps yet on the system. Is there something
> I
> need to do in addition to get the pps drivers in place?
>
> Regards
The pps-gpio driver creates devices named /dev/gpioppsN. You need to
create links to the /dev/ppsN numbers you want them assigned to (using
devfs.conf entries). The reason for this is that there may be many
different pps-generating devices on the system and the admin needs to
decide which ones link up to the pps devices specified in server
configuration lines in ntp.conf.
For example, on my beaglebone that I use for pps testing, my devfs.conf
has these entries:
link cuaU0 pps0
link cuau1 pps1
link dmtpps pps2
link gpiopps0 pps3
and my ntp.conf on that board has:
server 127.127.22.0 minpoll 4 maxpoll 4
fudge 127.127.22.0 stratum 0 refid ucom
server 127.127.22.1 minpoll 4 maxpoll 4
fudge 127.127.22.1 stratum 0 refid uart
server 127.127.22.2 minpoll 4 maxpoll 4
fudge 127.127.22.2 stratum 0 refid timr
server 127.127.22.3 minpoll 4 maxpoll 4
fudge 127.127.22.3 stratum 0 refid gpio
-- Ian
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1520865935.84937.169.camel>