oOn Fri, Jan 20, 2017 at 3:22 PM, Pavel Machek <pavel@xxxxxx> wrote: > Switched subject: Rob's work is great for GPS and bluetooth, but this > goes beyond it. Sure why not talk around a bit. >> In my simple opinion GPSes shound live in drivers/iio/gps simply by >> usecase association: streaming out a series of accelerometer readings >> periodically through IIOs chardevs and other data about the physical >> world is not any different from the GPS usecase that give you a stream >> of coordinates on where on this planet you are. > > That is... not quite how GPSes work. What interface would you propose? > It would be good to support error estimates in position/velocities and > AGPS data upload. Sorry for my ignorance. I have not had the opportunity to work directly with a GPS hardware. > Now, NMEA knows about some of the complexity (not AGPS), but gets the > details wrong. In particular, it would be good to have error estimates > and velocities from the same moment you get position estimates. NMEA if it is this: https://en.wikipedia.org/wiki/NMEA_0183 Seems to be a high-level format such as XML or CSV or any other $FAVOURITE_ASCII_TRANSPORT format. What we want to push into the ring buffer is of course the raw data that is produced by the GPS hardware, whatever that may be. If what we have is this text format we should not reverse-translate it back any more than modem AT commands, it doesn't make sense I guess. So NMEA processing would be in userspace. And if the GPS is just streaming this text data over to the client, like Marcel says, it is more reasonable to just feed that up to userspace (no policy in the kernel). I am however aware of certain hardware such as the ST Microelectronis STA2062 produced for Garmin, which is *not* connected to any external chip, and is not talking over serial to any RSx port, and does not have an embedded firmware running on another SoC in any special GPS chip. And it is unassisted. Maybe that is an oddity. In the mobile phone business I guess it could be more common to have a separate SoC that by way of standards just stream NMEA data. Fusing that with other sensor data (accelerometer, compass, etc) is again indeed a userspace task. I hope NMEA includes very good timestamps. Thanks, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
