On Mon, 29 Jan 2024 08:53:27 +0100 Paul Menzel <pmenzel@xxxxxxxxxxxxx> wrote: > Dear Andreas, > > > Thank you for your patch. > > > Am 28.01.24 um 18:33 schrieb Andreas Kemnade: > > Add a driver for the Air Independent Interface protocol used by some TI > > Wilink combo chips. Per default, send out just NMEA to userspace and turn > > on/off things at open()/close() but keep the door open for any > > sophisticated development regarding the AI2 protocol by having a kernel > > parameter to turn it into raw mode resembling /dev/tigps provided by some > > TI vendor kernels. > > It’d be great, if you could add the name the kernel parameter *ai2raw*, > and also document at least one of these vendor kernels. > > Could you give a high level overview of the driver design? > basically I rely on the hci_ll stuff for doing wakeup and initializing the firmware. So I queue up there another sort of TLV construction besides the Bluetooth packets using the hci_dev infrastructure and offload all the GNSS specific handling to a platform subdevice. So in raw AI2 mode, the input is just en/decapsulated into GPS_CH9_OP_READ/WRITE packets and sent/recv via the hci queuing system (gnss_recv_frame() / ai2_send_frame()). On top of that in NMEA mode, proper intialization is done at open()/close(). The commands are in ai2_compose_frame() prepared by adding checksums, escaping any occurance of 0x10 and adding start/end markes() In the rx path, the mechanism works the other way round and if the packet is an NMEA report it is sent to userspace. > What device did you test with? > As said in 0/3 I am testing with an Epson Moverio BT-200 containing a WL1283. Regards, Andreas
