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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c
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// SPDX-License-Identifier: GPL-2.0-only

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/* Copyright (c) 2024 Benjamin Tissoires

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 */

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#include "vmlinux.h"

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#include "hid_bpf.h"

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#include "hid_bpf_helpers.h"

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#include <bpf/bpf_tracing.h>

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#define VID_BETOP_2185PC        0x11C0

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#define PID_RAPTOR_MACH_2 0x5606

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HID_BPF_CONFIG(

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	HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_BETOP_2185PC, PID_RAPTOR_MACH_2),

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);

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/*

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 * For reference, this is the fixed report descriptor

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 *

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 * static const __u8 fixed_rdesc[] = {

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 *     0x05, 0x01,                    // Usage Page (Generic Desktop)        0

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 *     0x09, 0x04,                    // Usage (Joystick)                    2

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 *     0xa1, 0x01,                    // Collection (Application)            4

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       6

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 *     0x85, 0x01,                    //  Report ID (1)                      8

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       10

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 *     0x09, 0x30,                    //  Usage (X)                          12

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 *     0x75, 0x10,                    //  Report Size (16)                   14

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 *     0x95, 0x01,                    //  Report Count (1)                   16

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 *     0x15, 0x00,                    //  Logical Minimum (0)                18

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 *     0x26, 0xff, 0x07,              //  Logical Maximum (2047)             20

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 *     0x46, 0xff, 0x07,              //  Physical Maximum (2047)            23

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               26

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       28

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 *     0x09, 0x31,                    //  Usage (Y)                          30

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 *     0x75, 0x10,                    //  Report Size (16)                   32

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 *     0x95, 0x01,                    //  Report Count (1)                   34

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 *     0x15, 0x00,                    //  Logical Minimum (0)                36

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 *     0x26, 0xff, 0x07,              //  Logical Maximum (2047)             38

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 *     0x46, 0xff, 0x07,              //  Physical Maximum (2047)            41

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               44

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       46

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 *     0x09, 0x33,                    //  Usage (Rx)                         48

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 *     0x75, 0x10,                    //  Report Size (16)                   50

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 *     0x95, 0x01,                    //  Report Count (1)                   52

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 *     0x15, 0x00,                    //  Logical Minimum (0)                54

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 *     0x26, 0xff, 0x03,              //  Logical Maximum (1023)             56

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 *     0x46, 0xff, 0x03,              //  Physical Maximum (1023)            59

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               62

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 *     0x05, 0x00,                    //  Usage Page (Undefined)             64

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 *     0x09, 0x00,                    //  Usage (Undefined)                  66

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 *     0x75, 0x10,                    //  Report Size (16)                   68

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 *     0x95, 0x01,                    //  Report Count (1)                   70

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 *     0x15, 0x00,                    //  Logical Minimum (0)                72

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 *     0x26, 0xff, 0x03,              //  Logical Maximum (1023)             74

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 *     0x46, 0xff, 0x03,              //  Physical Maximum (1023)            77

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               80

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       82

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 *     0x09, 0x32,                    //  Usage (Z)                          84

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 *     0x75, 0x10,                    //  Report Size (16)                   86

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 *     0x95, 0x01,                    //  Report Count (1)                   88

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 *     0x15, 0x00,                    //  Logical Minimum (0)                90

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 *     0x26, 0xff, 0x03,              //  Logical Maximum (1023)             92

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 *     0x46, 0xff, 0x03,              //  Physical Maximum (1023)            95

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               98

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       100

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 *     0x09, 0x35,                    //  Usage (Rz)                         102

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 *     0x75, 0x10,                    //  Report Size (16)                   104

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 *     0x95, 0x01,                    //  Report Count (1)                   106

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 *     0x15, 0x00,                    //  Logical Minimum (0)                108

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 *     0x26, 0xff, 0x03,              //  Logical Maximum (1023)             110

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 *     0x46, 0xff, 0x03,              //  Physical Maximum (1023)            113

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               116

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       118

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 *     0x09, 0x34,                    //  Usage (Ry)                         120

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 *     0x75, 0x10,                    //  Report Size (16)                   122

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 *     0x95, 0x01,                    //  Report Count (1)                   124

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 *     0x15, 0x00,                    //  Logical Minimum (0)                126

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 *     0x26, 0xff, 0x07,              //  Logical Maximum (2047)             128

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 *     0x46, 0xff, 0x07,              //  Physical Maximum (2047)            131

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               134

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       136

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 *     0x09, 0x36,                    //  Usage (Slider)                     138

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 *     0x75, 0x10,                    //  Report Size (16)                   140

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 *     0x95, 0x01,                    //  Report Count (1)                   142

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 *     0x15, 0x00,                    //  Logical Minimum (0)                144

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 *     0x26, 0xff, 0x03,              //  Logical Maximum (1023)             146

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 *     0x46, 0xff, 0x03,              //  Physical Maximum (1023)            149

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               152

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 *     0x05, 0x09,                    //  Usage Page (Button)                154

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 *     0x19, 0x01,                    //  Usage Minimum (1)                  156

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 *     0x2a, 0x1d, 0x00,              //  Usage Maximum (29)                 158

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 *     0x15, 0x00,                    //  Logical Minimum (0)                161

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 *     0x25, 0x01,                    //  Logical Maximum (1)                163

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 *     0x75, 0x01,                    //  Report Size (1)                    165

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 *     0x96, 0x80, 0x00,              //  Report Count (128)                 167

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 *     0x81, 0x02,                    //  Input (Data,Var,Abs)               170

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       172

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 *     0x09, 0x39,                    //  Usage (Hat switch)                 174

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 *     0x26, 0x07, 0x00,              //  Logical Maximum (7)                176 // changed (was 239)

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 *     0x46, 0x68, 0x01,              //  Physical Maximum (360)             179

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 *     0x65, 0x14,                    //  Unit (EnglishRotation: deg)        182

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 *     0x75, 0x10,                    //  Report Size (16)                   184

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 *     0x95, 0x01,                    //  Report Count (1)                   186

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 *     0x81, 0x42,                    //  Input (Data,Var,Abs,Null)          188

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 *     0x05, 0x01,                    //  Usage Page (Generic Desktop)       190

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 *     0x09, 0x00,                    //  Usage (Undefined)                  192

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 *     0x75, 0x08,                    //  Report Size (8)                    194

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 *     0x95, 0x1d,                    //  Report Count (29)                  196

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 *     0x81, 0x01,                    //  Input (Cnst,Arr,Abs)               198

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 *     0x15, 0x00,                    //  Logical Minimum (0)                200

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 *     0x26, 0xef, 0x00,              //  Logical Maximum (239)              202

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 *     0x85, 0x58,                    //  Report ID (88)                     205

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 *     0x26, 0xff, 0x00,              //  Logical Maximum (255)              207

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 *     0x46, 0xff, 0x00,              //  Physical Maximum (255)             210

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 *     0x75, 0x08,                    //  Report Size (8)                    213

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 *     0x95, 0x3f,                    //  Report Count (63)                  215

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 *     0x09, 0x00,                    //  Usage (Undefined)                  217

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 *     0x91, 0x02,                    //  Output (Data,Var,Abs)              219

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 *     0x85, 0x59,                    //  Report ID (89)                     221

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 *     0x75, 0x08,                    //  Report Size (8)                    223

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 *     0x95, 0x80,                    //  Report Count (128)                 225

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 *     0x09, 0x00,                    //  Usage (Undefined)                  227

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 *     0xb1, 0x02,                    //  Feature (Data,Var,Abs)             229

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 *     0xc0,                          // End Collection                      231

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 * };

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 */

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/*

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 * We need to amend the report descriptor for the following:

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 * - the joystick sends its hat_switch data between 0 and 239 but

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 *   the kernel expects the logical max to stick into a signed 8 bits

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 *   integer. We thus divide it by 30 to match what other joysticks are

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 *   doing

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 */

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SEC(HID_BPF_RDESC_FIXUP)

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int BPF_PROG(hid_fix_rdesc_raptor_mach_2, struct hid_bpf_ctx *hctx)

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{

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	__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */);

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	if (!data)

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		return 0; /* EPERM check */

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	data[177] = 0x07;

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	return 0;

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}

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/*

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 * The hat_switch value at offsets 33 and 34 (16 bits) needs

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 * to be reduced to a single 8 bit signed integer. So we

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 * divide it by 30.

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 * Byte 34 is always null, so it is ignored.

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 */

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SEC(HID_BPF_DEVICE_EVENT)

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int BPF_PROG(raptor_mach_2_fix_hat_switch, struct hid_bpf_ctx *hctx)

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{

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	__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 64 /* size */);

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	if (!data)

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		return 0; /* EPERM check */

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	if (data[0] != 0x01) /* not the joystick report ID */

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		return 0;

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	data[33] /= 30;

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	return 0;

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}

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HID_BPF_OPS(raptor_mach_2) = {

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	.hid_rdesc_fixup = (void *)hid_fix_rdesc_raptor_mach_2,

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	.hid_device_event = (void *)raptor_mach_2_fix_hat_switch,

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};

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SEC("syscall")

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int probe(struct hid_bpf_probe_args *ctx)

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{

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	ctx->retval = ctx->rdesc_size != 232;

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	if (ctx->retval)

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		ctx->retval = -EINVAL;

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	/* ensure the kernel isn't fixed already */

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	if (ctx->rdesc[177] != 0xef) /* Logical Max of 239 */

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		ctx->retval = -EINVAL;

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	return 0;

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}

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char _license[] SEC("license") = "GPL";

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