Hi Benjamin, Ah that makes sense, it was Peter who directed me towards a driver-based solution. Thank you for your detailed response, this is everything I need to get started. David On 25 January 2017 at 05:19, Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx> wrote: > On Tue, Jan 24, 2017 at 5:12 AM, David Farrell <davidnmfarrell@xxxxxxxxx> wrote: >> Hi folks, >> >> I have an adonit jot pixel bluetooth stylus. Adapting someone else's >> code (source http://gerev.github.io/laptop-cintiq/) I have it working >> with uinput, posting ABS_PRESSURE and BTN_1/2 event codes and so on. >> I'm running upstream. >> >> What I'm wondering is; as the stylus relies on a bluetooth connection, >> is it a suitable device to develop a kernel input driver for? And if >> yes, are there any reference drivers you'd recommend I look at? > > Hi, > > Coincidentally, I talked to Peter yesterday about this very same > stylus. I can only talk for the Wacom Creative Stylus 2, which I have, > but which I believe is similar to yours in many aspects. > So if your stylus is similar to mine, it uses BLE (or Bluetooth 4). > And in that case, you don't really need to write a kernel driver, but > more a bluez plugin in the same way HID over GATT (HID over BLE) is > working. This requires connecting over BLE to the stylus, then create > a uhid device (and you will have to write the report descriptors > matching your device by reverse engineering it), and inject that uhid > device in the same way bluez does for HID over GATT. Then you just > need to forward the raw events from the device to the uhid node and > the kernel will simply translate the events for you. > > As a starter, you can have a look at profiles/input/hog.c and > profiles/input/hog-lib.c in the bluez repository. > > Of course, if the stylus is not using BLE, then it perfectly makes > sense to write a full kernel driver for it (but I strongly suspect it > uses BLE). > > Cheers, > Benjamin > >> >> Many thanks in advance >> >> David >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-input" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
