[LinuxPPS] [PATCHv2 6/6] pps: add parallel port PPS client

[Miroslav Lichvar]

On Wed, Feb 24, 2010 at 03:28:17PM +0300, Alexander Gordeev wrote:
> Add parallel port PPS client. It uses a standard method for capturing
> timestamps for assert edge transitions: getting a timestamp soon after
> an interrupt has happened. This is not a very precise source of time
> information due to interrupt handling delays. However, timestamps for
> clear edge transitions are much more precise because the interrupt
> handler continuously polls hardware port until the transition is done.
> Hardware port operations require only about 1us so the maximum error
> should not exceed this value. This was my primary goal when developing
> this client.

Is there a GPS receiver that can be used with this client directly? It
seems that the pulse width needs to be set to something like 99.9995%,
but mine can be configured only to 98%.

I think it would be useful to add a module parameter (or detect it
automatically) to disable the clear edge detection and report
only assert events.

-- 
Miroslav Lichvar