Re: [gpsd-dev] PPS over USB

[Eric S. Raymond]

Hal Murray <address@hidden>:
> 
> address@hidden said:
> > You can generate one by grepping for TIOCMIWAIT in the driver tree.  Gary
> > did this as one point.  The PL2303 is defintely good, the CP210x bad. 
> 
> Thanks.  For the archives, here is what I see in a handy kernel source tree.
> 
> address@hidden linux-3.2.12]$ grep -r TIOCMIWAIT ./drivers/usb/serial -l
> ./drivers/usb/serial/ark3116.c
> ./drivers/usb/serial/ti_usb_3410_5052.c
> ./drivers/usb/serial/oti6858.c
> ./drivers/usb/serial/cypress_m8.c
> ./drivers/usb/serial/io_edgeport.c
> ./drivers/usb/serial/spcp8x5.c
> ./drivers/usb/serial/ssu100.c
> ./drivers/usb/serial/ch341.c
> ./drivers/usb/serial/mos7840.c
> ./drivers/usb/serial/ftdi_sio.c
> ./drivers/usb/serial/pl2303.c
> ./drivers/usb/serial/io_ti.c
> ./drivers/usb/serial/mct_u232.c
> ./drivers/usb/serial/mos7720.c
> address@hidden linux-3.2.12]$ 

Our hotplug rules, which have been stable for some time and thus probably
enumerate the subset of serial-to-USB adapters found in GPSes pretty well, 
give us these:

# Prolific Technology, Inc. PL2303 Serial Port [linux module: pl2303]
# FTDI 8U232AM / FT232 [linux module: ftdi_sio]
# Cypress M8/CY7C64013 (Delorme uses these) [linux module: cypress_m8]
# Garmin International GPSmap, various models (tested with Garmin GPS 18 USB)  
[linux module: garmin_gps]
# Cygnal Integrated Products, Inc. [linux module: cp210x]
# u-blox AG, u-blox 5 (tested with Navilock NL-402U) [linux module: cdc_acm]

I think we can deduce from this the following:

PL2303, Cypress M8, FTDI SIO - good

CP2120x - bad (we already knew this). 
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>