Hi Dmitry,

Can this be done via udev keymaps/hwdb instead of kernel driver?

I couldn't remap hotkeys.
evtest command output is below.

Fn+F1(sleep)
Event: time 1463068038.605052, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068038.605052, -------------- EV_SYN ------------
Event: time 1463068038.669030, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068038.669030, -------------- EV_SYN ------------

Fn+F2(Airplane mode)
Event: time 1463068094.753052, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068094.753052, -------------- EV_SYN ------------
Event: time 1463068094.805040, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068094.805040, -------------- EV_SYN ------------

Fn+F5(Display Brightness Down)
Event: time 1463068127.261051, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068127.261051, type 3 (EV_ABS), code 56
(ABS_MT_BLOB_ID), value 1
Event: time 1463068127.261051, -------------- EV_SYN ------------
Event: time 1463068127.313042, type 3 (EV_ABS), code 56
(ABS_MT_BLOB_ID), value 0
Event: time 1463068127.313042, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068127.313042, -------------- EV_SYN ------------

Fn+F6(Display Brightness Up)
Event: time 1463068227.209051, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068227.209051, -------------- EV_SYN ------------
Event: time 1463068227.277042, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068227.277042, -------------- EV_SYN ------------

Fn+F7(Display Power Off)
Event: time 1463068227.209051, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068227.209051, -------------- EV_SYN ------------
Event: time 1463068227.277042, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068227.277042, -------------- EV_SYN ------------

Fn+F9 (Touchpad toggle)
Event: time 1463068441.937052, type 3 (EV_ABS), code 40 (ABS_MISC), value 0
Event: time 1463068441.937052, -------------- EV_SYN ------------
Event: time 1463068441.989049, type 3 (EV_ABS), code 40 (ABS_MISC), value 1
Event: time 1463068441.989049, -------------- EV_SYN ------------

Below volume control hotkeys work out of the box.

Fn+F10 (Mute)
Event: time 1463068508.229058, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e2
Event: time 1463068508.229058, type 1 (EV_KEY), code 113 (KEY_MUTE), value 1
Event: time 1463068508.229058, -------------- EV_SYN ------------
Event: time 1463068508.281048, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e2
Event: time 1463068508.281048, type 1 (EV_KEY), code 113 (KEY_MUTE), value 0
Event: time 1463068508.281048, -------------- EV_SYN ------------

Fn+F11(Volume Down)
Event: time 1463068543.501053, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00ea
Event: time 1463068543.501053, type 1 (EV_KEY), code 114
(KEY_VOLUMEDOWN), value 1
Event: time 1463068543.501053, -------------- EV_SYN ------------
Event: time 1463068543.565055, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00ea
Event: time 1463068543.565055, type 1 (EV_KEY), code 114
(KEY_VOLUMEDOWN), value 0
Event: time 1463068543.565055, -------------- EV_SYN ------------

Fn+F12(Volume Up)
Event: time 1463068575.305053, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e9
Event: time 1463068575.305053, type 1 (EV_KEY), code 115 (KEY_VOLUMEUP), value 1
Event: time 1463068575.305053, -------------- EV_SYN ------------
Event: time 1463068575.345093, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e9
Event: time 1463068575.345093, type 1 (EV_KEY), code 115 (KEY_VOLUMEUP), value 0
Event: time 1463068575.345093, -------------- EV_SYN ------------

If there is any method to remap above hotkeys via udev,please tell me.

Best regards.
-- 
Yusuke FUJIMAKI