made some progress atleast, now i got all the pieces working, just cant figure how to glue it together.
installed newer bluetooth stack bluez 5.50
volumio@passatmediacenter:~$ dmesg | grep -i -E "bluetooth|input"
[ 14.914448] Bluetooth: Core ver 2.22
[ 14.914544] Bluetooth: HCI device and connection manager initialized
[ 14.914575] Bluetooth: HCI socket layer initialized
[ 14.914593] Bluetooth: L2CAP socket layer initialized
[ 14.914636] Bluetooth: SCO socket layer initialized
[ 15.094668] Bluetooth: HCI UART driver ver 2.3
[ 15.094684] Bluetooth: HCI UART protocol H4 registered
[ 15.094769] Bluetooth: HCI UART protocol Three-wire (H5) registered
[ 15.094990] Bluetooth: HCI UART protocol Broadcom registered
[ 15.672346] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 15.672353] Bluetooth: BNEP filters: protocol multicast
[ 15.672365] Bluetooth: BNEP socket layer initialized
[ 18.482647] input: Passat SWC kit as /devices/virtual/misc/uhid/0005:5B3A:6B2A.0001/input/input0
[ 18.489269] hid-generic 0005:5B3A:6B2A.0001: input,hidraw0: BLUETOOTH HID v90.8c Device [Passat SWC kit] on B8:27:EB:55:7E:86
So my device is registered as hid device by the system, auto connect and registering gatt charasterics is working fine.
btmon receives raw data.
Bluetooth monitor ver 5.50
= Note: Linux version 4.19.118-v7l+ (armv7l) 0.712574
= Note: Bluetooth subsystem version 2.22 0.712578
= New Index: B8:27:EB:55:7E:86 (Primary,UART,hci0) [hci0] 0.712580
= Open Index: B8:27:EB:55:7E:86 [hci0] 0.712582
= Index Info: B8:27:EB:55:7E:86 (Broadcom Corporation) [hci0] 0.712583
@ MGMT Open: bluetoothd (privileged) version 1.14 {0x0001} 0.712585
@ MGMT Open: btmon (privileged) version 1.14 {0x0002} 0.712608
> ACL Data RX: Handle 64 flags 0x02 dlen 10 #21 [hci0] 103.280748
ATT: Handle Value Notification (0x1b) len 5
Handle: 0x0010
Data: 020800
and evdev does create input device in /dev/input
volumio@passatmediacenter:~$ ls /dev/input
event0 mice
the proplem is i cannot receive any data from within the event0 with cat command or python script, anyone have idea?