RFC HID: Transport Driver Cleanup

Hi

This series provides some cleanups for HID transport drivers:
Patch #1: Cleanup which can be picked up
Patch #2-#6: Provide generic hidinput_input_event() helpers Patch #7-#8: Transport-driver Cleanup

Patch #7-#8 is an attempt to clean up the transport driver callbacks. Lets look at how the following hooks are currently implemented:
1) GET_REPORT: Issue a synchronous GET_REPORT via the ctrl-channel
2) SET_REPORT: Issue a synchronous SET_REPORT via the ctrl-channel
3) OUTPUT: Issue an asynchronous OUTPUT report on the intr-channel

USB-HID:
1) GET_REPORT can be issued via ->hid_get_raw_report() for all three report types correctly.
2) SET_REPORT can only be issued for FEATURE reports via ->hid_output_raw_report(). INPUT and OUTPUT reports on the same callback cause an asynchronous report on the intr channel.
3) OUTPUT reports can be issued via ->hid_output_raw_report() as described above in SET_REPORT.

HIDP:
1) GET_REPORT: same as for USB-HID
2) SET_REPORT can only be issued for FEATURE reports via ->hid_output_raw_report(). SET_REPORT for INPUT reports is forbidden (why?) and SET_REPORT for OUTPUT reports is actually implemented as 3)
3) OUTPUT reports can be issued via ->hid_output_raw_report().

I2C:
1) GET_REPORT implemented for INPUT and FEATURE via ->hid_get_raw_report(). Forbidden for OUTPUT reports (why?).
2) SET_REPORT can be issued for OUTPUT and FEATURE reports via

    ->hid_output_raw_report() but is forbidden for INPUT reports (why?).

3) OUTPUT reports cannot be issued at all.

UHID:
1) GET_REPORT only supported for FEATURE via ->hid_get_raw_report()
2) SET_REPORT not supported at all
3) OUTPUT supported via ->hid_output_raw_report()

As this is all very inconsistent, I added two new callbacks:
->raw_request() is the same as ->request() but with a raw buffer. It should be implemented by the transport drivers as SET/GET_REPORT calls in the ctrl-channel.

->output_report() is supposed to send an OUTPUT report on the intr-channel (same channel asynchronous input reports are received from).

Please see the hid-transport.txt for a description. The last patch tries to implement them. I have no idea how to implement it for i2c, it seems that i2c multiplexes ctrl and intr channels on a single i2c channel. I don't know how to send raw output reports at all.. Help welcome!

If there is more interest in this work, I will clean it up, try to convert the other hid_ll_driver drivers and resend as a proper patchset.

Cheers
David

David Herrmann (8):
HID: usbhid: make usbhid_set_leds() static
HID: usbhid: update LED fields unlocked
HID: input: generic hidinput_input_event handler
HID: usbhid: use generic hidinput_input_event()
HID: i2c: use generic hidinput_input_event()
HID: uhid: use generic hidinput_input_event()
HID: add transport driver documentation
HID: implement new transport-driver callbacks

 Documentation/hid/hid-transport.txt | 299 ++++++++++++++++++++++++++++++++++++
 Documentation/hid/uhid.txt          |   4 +-
 drivers/hid/hid-input.c             |  80 +++++++++-
 drivers/hid/i2c-hid/i2c-hid.c       |  24 ---
 drivers/hid/uhid.c                  |  52 ++++---
 drivers/hid/usbhid/hid-core.c       | 144 +++++++++--------
 drivers/hid/usbhid/usbhid.h         |   3 -
 include/linux/hid.h                 |  10 +-
 include/uapi/linux/uhid.h           |   4 +-
 net/bluetooth/hidp/core.c           |  90 +++++++++++
 10 files changed, 590 insertions(+), 120 deletions(-)
 create mode 100644 Documentation/hid/hid-transport.txt

1.8.3.2