Hi This is the second revision of the UHID driver. It basically allows to register hid_ll_drivers in user-space. This is needed to implement Bluetooth HoG (HID over GATT) as discussed earlier. Changes: - Improved documentation - Added example which emulates a 3-button mouse with wheel in user-space - Fixed some remaining bugs I didn't change any major parts. I checked that writev/readv work correctly and I documented how to use it in ./Documentation/hid/uhid.txt. For a full example please see ./samples/uhid/uhid-example.c. While developing it I also considered moving HIDP to user-space. If we do BT-HoG in user-space, it should be easier to also move HIDP to user-space. The current in-kernel HIDP is buggy, anyway. Still open points: - How do I get a proper "parent" pointer for uhid->hid->dev.parent? I could use the uhid misc device as parent or is there some device-struct inside "struct file"? - Should user-space be able to provide "uniq" and "phys" names for HID-devices? - uhid_event is quite big (>4KB) which makes uhid_device really big (~70KB). Should I allocate the ring-buffer dynamically to avoid this? - Should I provide the quirks field to user-space? Probably as part of UHID_START? - Could someone review x32 COMPAT stuff? I tried to align all the public structures correctly so I could even remove the __packed attribute. Anyway, I thought keeping it is probably better for future extensions. I spent some time on the locks and they seem all fine. I couldn't find any races. Jiri, Marcel, could you review the design and tell me what you think? A short notice about the protocol: User-space is allowed to send only as much data as is needed for the event. That is, when sending the UHID_DESTROY event (which has no payload) it would be actually enough to only send a __u32 field (ev->type) with write(). This is not to speed up the write()s or read()s but rather to allow extending the uhid_event structure in the future. We can actually add arbitrary extra event-types and still keep ABI compatibility. Therefore, I thought of adding an "uhid_version" field to UHID_CREATE so user-space can define what UHID protocol it is using. Regards David David Herrmann (1): HID: User-space I/O driver support for HID subsystem Documentation/hid/uhid.txt | 152 ++++++++++++++ drivers/hid/Kconfig | 21 ++ drivers/hid/Makefile | 2 +- drivers/hid/uhid.c | 473 +++++++++++++++++++++++++++++++++++++++++++ include/linux/Kbuild | 1 + include/linux/uhid.h | 84 ++++++++ samples/uhid/Makefile | 10 + samples/uhid/uhid-example.c | 381 ++++++++++++++++++++++++++++++++++ 8 files changed, 1123 insertions(+), 1 deletion(-) create mode 100644 Documentation/hid/uhid.txt create mode 100644 drivers/hid/uhid.c create mode 100644 include/linux/uhid.h create mode 100644 samples/uhid/Makefile create mode 100644 samples/uhid/uhid-example.c -- 1.7.9.4 -- 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
