// vim:syntax=c:
// docs at https://drive.google.com/?tab=mo&pli=1&authuser=0#folders/0BxbRzx7vEV7eWmgwazJ3NUFfQ28 (found at http://code.google.com/p/chromium/issues/detail?id=175572)
struct dj_report {
	u8 report_id;
	u8 device_index;
	u8 report_type;
	u8 report_params[DJREPORT_SHORT_LENGTH - 3];
};

// char magic_sequence[] = {0x10, 0xFF, 0x80, 0xB2, 0x01, 0x00, 0x00};

#define REPORT_TYPE_KEYBOARD			0x01
#define REPORT_TYPE_MOUSE			0x02
#define REPORT_TYPE_CONSUMER_CONTROL		0x03
#define REPORT_TYPE_SYSTEM_CONTROL		0x04

#define REPORT_TYPE_MEDIA_CENTER		0x08

#define REPORT_TYPE_LEDS			0x0E

#define REPORT_TYPE_NOTIF_DEVICE_UNPAIRED	0x40
#define REPORT_TYPE_NOTIF_DEVICE_PAIRED		0x41
#define REPORT_TYPE_NOTIF_CONNECTION_STATUS	0x42

#define REPORT_TYPE_NOTIF_ERROR			0x7F

#define REPORT_TYPE_CMD_SWITCH			0x80
#define REPORT_TYPE_CMD_GET_PAIRED_DEVICES	0x81

	dj_report->report_id = REPORT_ID_DJ_SHORT;
	dj_report->device_index = 0xFF;
	dj_report->report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);

report_id	= 0x10;
device_index	= 0xFF;
report_type	= 0x80; // REPORT_TYPE_CMD_SWITCH
report_params	= {0xB2, 0x01, 0x00, 0x00};
// { 0xB2 , Connect Devices, Device Number, Open Lock Timeout }
// 		= {0xb2, 0x01, 0x50, 0x3c}
// observation: S b203 0100 perform unpair
//              S b201 533c when discovery is enabled (with no paired devices)
//              R b200 0000 when discovery is enabled (no paired devices, waiting; also recvd when unpaired while in Advanced mode)
//              S b202 5394 when discovery is disabled (both with 1 paired kbd and no paired kbd; explicitly issued when closing pair program)
// 0:1 1 address
// 1:3 3 value (0 is returned on succesfully setting register)
// Related to type 0x4A

// observations + guesses
// issued after 10 ff CMD_SWITCH b2 .. .. ..
report_id       = 0x10
device_index    = 0xFF
report_type     = 0x4A // receiver status - open for new devices?
//              R 0100 0000 discovery enabled
//              R 0001 0000 discovery disabled (issued after timeout)
//              R 0000 0000 discovery disabled (after CMD_SWITCH b200 0000; succesful pair)

// 00000000 00000000 is sent when device is turned off, "null report"?

// No paired devices, just started program:
// output   report_id=10   dev_idx=ff RECV   type=83                           parms=b5030000
//    ep3   report_id=11   dev_idx=ff RECV   type=83                           parms=b503af4f95 ea150609 00000000 00000000
// No paired devices (same for unpaired kbd off/on), just started program:
// output   report_id=10   dev_idx=ff RECV   type=83 ?CMD_DEVICE_INFO          parms=b5030000
//    ep3   report_id=11   dev_idx=ff RECV   type=83 ?CMD_DEVICE_INFO          parms=b503af4f95 ea15060a 00000000 00000000
// Press "Advanced", unpaired (same for unpaired kbd on/off):
// output   report_id=10   dev_idx=ff RECV   type=83 ?CMD_DEVICE_INFO          parms=b3000000
//    ep3   report_id=11   dev_idx=ff RECV   type=83 ?CMD_DEVICE_INFO          parms=b308000000 00000000 00000000 00000000

/*
report_id=10; dev_id=01 for Sent0+Recv0 and Sent1+Recv1, but ff for Sent1+Recv2
  Sent0     Recv0
         00120100*
0d000000 810d0200*
07000000 07050000

  Sent1    Recv1   Recv2
f1010000 f1012201 f1011201
f1020000 f1020019 f1020019
f1030000 f1030007 81f10300*
f1040000 f1040201 f1040214

*) type=8f instead of 81 CMD_GET_PAIRED_DEVICES
Order = Sent0+Recv0, Sent1+Recv1, Sent1+Recv2 (+ = interleaved)
*/


// Discover? (click Advanced and get a lot of this spam)
// send: report_id=10   dev_idx=ff   type=83                           parms=b3000000                                   # report yourself guys?
//
// recv: report_id=11   dev_idx=ff   type=83                           parms=b3a1000000 00000000 00000000 00000000
// ep3   report_id=11   dev_idx=ff   type=83                           parms=b32a000000 00000000 00000000 00000000      # byte 2 is channel/encrypt key???
// ep3   report_id=11   dev_idx=ff   type=83                           parms=b331000000 00000000 00000000 00000000      # No devices turned on
// ep3   report_id=11   dev_idx=ff   type=83                           parms=b334000000 00000000 00000000 00000000      # Device pair step 1 (after Sent0+Recv0)
// ep3   report_id=11   dev_idx=ff   type=83                           parms=b336000000 00000000 00000000 00000000      # Device pair step 2 (after Sent1+Recv1)
// ep3   report_id=11   dev_idx=ff   type=83                           parms=b338000000 00000000 00000000 00000000      # Device just paired (after Sent1+Recv2)


// Unpair:
// send: report_id=10   dev_idx=ff   type=80 CMD_SWITCH                parms=b2030100                                   # R: Unpair device request
//
// recv: report_id=03   dev_idx=00   type=00                           parms=0000
// recv: report_id=10   dev_idx=01   type=40 NOTIF_DEVICE_UNPAIRED     parms=02000000
// recv: report_id=00   dev_idx=00   type=00                           parms=0000000000
//
// recv: report_id=20   dev_idx=01   type=40 NOTIF_DEVICE_UNPAIRED     parms=0000000000 00000000 000000
//
// recv: report_id=10   dev_idx=ff   type=80 CMD_SWITCH                parms=b2000000                                   # K: Ready to accept other receiver?

// Prepare switch?
// send: report_id=10   dev_idx=ff   type=80 CMD_SWITCH                parms=b201533c                                   # R: Looking for devices?
// recv: 
// recv: report_id=10   dev_idx=ff   type=4a                           parms=01000000                                   # K: Hi I am a device
// recv: 
// recv: report_id=10   dev_idx=ff   type=80 CMD_SWITCH                parms=b2000000                                   # K: I want to pair with you
// Switch timeout? (+/- 60 seconds)
// recv: report_id=10   dev_idx=ff   type=4a                           parms=00010000                                   # K: Nevermind, nobody responded

// Turn on kbd while pair program is waiting for recv
// recv: report_id=10   dev_idx=01   type=41 NOTIF_DEVICE_PAIRED       parms=04611020                                   # L: I just turned myself on
//
// send: report_id=10   dev_idx=ff   type=83                           parms=b5400000                                   # R: Hey, wanna join me?
// recv: report_id=20   dev_idx=01   type=41 NOTIF_DEVICE_PAIRED       parms=0010201a40 00000000 000000
//
// recv: report_id=10   dev_idx=ff   type=4a                           parms=00000000
//
// recv: report_id=11   dev_idx=ff   type=83                           parms=b540044b38 30300000 00000000 00000000
//
// send: report_id=10   dev_idx=ff   type=83                           parms=b5300000
//
// recv: report_id=11   dev_idx=ff   type=83                           parms=b530fb841b 861a4000 00070000 00000000
// b530
// fb841b 86                    Serial No
// 1a4000 00070000 00000000     ???
//
// recv: report_id=10   dev_idx=01   type=41 NOTIF_DEVICE_PAIRED       parms=04a11020                                   # I am already paired? (0x6_ -> 0xa_, 0110 -> 1010); Also sent when turning on paired kbd
// type=41 Device Connection
// 04 0000 0100 - Unifying protocol
// a1 1010 0001 - DeviceType=Keyboard; Link is encrypted; Link is established; Packet with payload
// 10 0001 0000 - Wireless PID LSB
// 20 0010 0000 - Wireless PID MSB

// continued switch.
// send: report_id=10   dev_idx=01   type=00                           parms=12283f94
//     : report_id=10   dev_idx=01   type=4b                           parms=01000000
//
//     : report_id=10   dev_idx=01   type=8f                           parms=00120100
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=0d000000
//
//     : report_id=10   dev_idx=01   type=8f                           parms=810d0200
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=07000000
//
//     : report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=07050000
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1010000
//
//     : report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1012201
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1020000
//
//     : report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1020019
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1030000
//
//     : report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1030007
//
// send: report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1040000
//
//     : report_id=10   dev_idx=01   type=81 CMD_GET_PAIRED_DEVICES    parms=f1040201
//
// send: report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1010000
//     : report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1011201
//
// send: report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1020000
//     : report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1020019
//
// send: report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1030000
//     : 
//     : report_id=10   dev_idx=ff   type=8f                           parms=81f10300
//     : 
// send: report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1040000
//     : report_id=10   dev_idx=ff   type=81 CMD_GET_PAIRED_DEVICES    parms=f1040214


// http://tequals0.wordpress.com/2011/11/01/reverse-engineering-logitech-unifying-usb-protocol/
/*
T:  Bus=05 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#=  3 Spd=12   MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=046d ProdID=c52b Rev=12.01
S:  Manufacturer=Logitech
S:  Product=USB Receiver
C:* #Ifs= 3 Cfg#= 1 Atr=a0 MxPwr= 98mA
I:* If#= 0 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=01 Driver=usbhid
E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=8ms
I:* If#= 1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=02 Driver=usbhid
E:  Ad=82(I) Atr=03(Int.) MxPS=   8 Ivl=2ms
I:* If#= 2 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
E:  Ad=83(I) Atr=03(Int.) MxPS=  32 Ivl=2ms

b=$'\e[1;32m';e=$'\e[m';sudo cat /sys/kernel/debug/usb/usbmon/5u | sed -ur "s/= (..)(..)(..)(..) (..)(....)(..)/=   report_id=$b\1$e   dev_idx=$b\2$e   type=$b\3$e   parms=$b\4\5 \6 \7$e/"

see lt/usbmon.awk
awk -vOFS='   ' 'function l(s){return "\033[1;32m" s "\033[m"}{if(match($0,/(.*? = )(..)(..)(..)(..) (.*)/,a)){printf("%-85s",$0);print "report_id=" l(a[2]), "dev_idx=" l(a[3]), "type=" l(a[4]), "parms=" l(a[5] a[6])}else print "\033[1;30m" $0 "\033[m"}'

*/