[Buildroot] Device creation

[Bill Borton]

Read your ENTIRE directions.  After showing you how to use ldattach and
udev to create the devices it says:

"Alternatively, you can create the proper device nodes with the mknod
utility. Please refer to the appropriate manual pages in either case."


Now, re-hashing my first two replies:

If you have your kernel configured correctly and your PPS hooked to DCD you
should have a /sys/class/pps/pps0 entry.  If you do not, you need to figure
out why before continuing.

If you have a /sys/class/pps/pps0 entry you can use mknod to create
/dev/pps0: "mknod -m 0664 /dev/pps0 c 252 0"  The arguments for mknod
can be found in /sys/class/pps/pps0/dev.

You do not need ldattach or udev.

-Bill


On Wed, 13 Apr 2011 17:14:45 -0400
Marc Leclerc <marc-leclerc at signaturealpha.com> wrote:
> Seems I am kind of stuck on the setup instructions where i should try 
> ldattach.
> buildroot only supports util-linux 2.13pre7 where as ldattach is only 
> supplied starting
> at 2.14. any chance to have support for the latest in buildroot?
> 
> Thanks
> 
> On 2011-04-08 17:56, Bill Borton wrote:
> > 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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