[Buildroot] Device creation

[Bill Borton]

You mean /sys/class/pps is empty?   I would check to make sure
you have everything you need in your kernel.

sysfs support?
pps support?
pps line discipline? (pps is connected to carrier detect. Correct?)

Again, you will not have pps on ttyS1.  It is physically connected to
DCD of your port but it will be it's own device.

-Bill

p.s.  This is a kernel/linux-pps issue.  There are better forums to
discuss this and a lot of info on-line...  Pretty much everything you
need is in the link you provided in your first post.  Read through it
again and play around a bit.



On Fri, 8 Apr 2011 16:33:55 -0400
"Marc Leclerc" <marc-leclerc at signaturealpha.com> wrote:
> Hi,
> 
> Thanks for this info, it will prove usefull. I seem to have a problem with 
> the kernel hooking up to my pps on ttyS1.
> 
> on startup i do see PPS line dicipline registered but the folder 
> /sys/stat/pps is empty. we have validated that the pps signal is pulsing at 
> 9V
> 
> Any clue why?
> 
> Thanks again
> 
> -----Original Message----- 
> From: Bill Borton
> Sent: Thursday, April 07, 2011 5:34 PM
> To: buildroot at busybox.net
> Subject: Re: [Buildroot] Device creation
> 
> On Thu, 7 Apr 2011 13:23:32 -0400
> "Marc Leclerc" <marc-leclerc at signaturealpha.com> wrote:
> > Hi, I am trying to get linuxpps working on my board using ntp. there are
> > steps described at
> > http://wiki.enneenne.com/index.php/LinuxPPS_installation which says to
> > use ldattach to assign the pps signal but so it seem I do not have
> > ldattach on my buildroot system and tryin to compile util-linux led to
> > compilation errors. Just wondering if anyone here has the know how to
> > get my /dev/pps0 created and assigned to my /dev/ttyS1. the steps also
> > mentions using udev to get the /dev/pps0 created, i have tried installing 
> > and
> > using it and it just messed up my other links
> >
> > Best regards
> 
> /dev/pps0 is it's own device.  Look in /sysfs/class/pps/pps0/dev (you did 
> build
> support into your kernel, correct?) for the details and use mknod to create 
> it:
> 
> mknod -m 0664 /dev/pps0 c 252 0
> 
> 
> If you are trying to bring up ntpd with the generic NMEA driver you will
> need to make a couple links to your ttyS1 and pps0:
> 
> ln -s /dev/ttyS1 /dev/gps0
> ln -s /dev/pps0 /dev/gpspps0
> 
> /dev/gps0 (ttyS1) has your nmea stream.
> /dev/gpspps0 (pps0) has your pps.
> 
> -Bill
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