Re: LinuxPPS & spinlocks
Satyam Sharma infradead.org> writes:
> On Mon, 30 Jul 2007, Rodolfo Giometti wrote:
>
> > On Mon, Jul 30, 2007 at 10:33:35AM +0530, Satyam Sharma wrote:
> > Currently the RFC says to you that you should open the serial port:
> >
> > fd = open("/dev/ttyS0", ...);
>
> No, it does *NOT*. All it says is:
>
> The time_pps_create() is used to convert an already-open UNIX file
> descriptor, for an appropriate special file, into a PPS handle.
>
> See? What I said is precisely the implementation the RFC envisages
> (and the only sane way to implement it too).
If we were totally rigurous about representing each device as a device node,
your solution would be fine. But we don't.
The clocksource model (/sys/devices/system/clocksource) is a better way to
go. One sysfs file is used to enumerate the possible sources and another is
used to read or set the current source. No new system calls; no new ioctls.
-ch
ch (at) murgatroid (dot) com
ch (at) hpl (dot) hp (dot) com
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Re: LinuxPPS spinlocks
Satyam Sharma satyam at infradead.org writes: On Mon, 30 Jul 2007, Rodolfo Giometti wrote: On Mon, Jul 30, 2007 at 10:33:35AM +0530, Satyam Sharma wrote: Currently the RFC says to you that you should open the serial port: fd = open(/dev/ttyS0, ...); No, it does *NOT*. All it says is: The time_pps_create() is used to convert an already-open UNIX file descriptor, for an appropriate special file, into a PPS handle. See? What I said is precisely the implementation the RFC envisages (and the only sane way to implement it too). If we were totally rigurous about representing each device as a device node, your solution would be fine. But we don't. The clocksource model (/sys/devices/system/clocksource) is a better way to go. One sysfs file is used to enumerate the possible sources and another is used to read or set the current source. No new system calls; no new ioctls. -ch ch (at) murgatroid (dot) com ch (at) hpl (dot) hp (dot) com - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
