Hi Nikolaus,

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I am actually not convinced that GPS should be represented as
/dev/ttyS0 or similar TTY. It think they deserve their own driver
exposing them as simple character devices. That way we can have a
proper DEVTYPE and userspace can find them correctly. We can also
annotate them if needed for special settings.

I would _love_ to see that happen, but what about the GPS line
discipline that we have today?  How would that match up with a char
device driver?

./drivers/usb/serial/garmin_gps.c ?

Hmm, some cleanups would be welcome there... plus it would be good to
know what is its interface to userland... it is not easily apparent
from the code.

Actually, having some kind of common support for GPSes in the kernel
would be nice. (Chardev that spits NMEA data?

Yes and no. How do you apply tcsetattr to such a device? More or less
by implementing another tty stack?

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) For example N900 GPS is
connected over network (phonet) interface, with userland driver
translating custom protocol into NMEA. Not very nice from "kernel
should provide hardware abstraction" point of view.

Indeed. In such a case the translation should be done in the kernel.
But it is not necessary for devices that already provide NEMA over UART.
Still user-space should be able to tcsetattr how it wants to see the records
(mainly CR/LF translations).

I disagree here. NMEA is a standard and the kernel should just enforce framing of NMEA sentences. It makes no difference what the CR/LF is. Userspace gets full sentences.

Regards

Marcel