1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2024 Red Hat, Inc 3 */ 4 5 #include "vmlinux.h" 6 #include "hid_bpf.h" 7 #include "hid_bpf_helpers.h" 8 #include "hid_report_helpers.h" 9 #include <bpf/bpf_tracing.h> 10 11 #define VID_HUION 0x256C 12 #define PID_DIAL_2 0x0060 13 14 15 HID_BPF_CONFIG( 16 HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_HUION, PID_DIAL_2), 17 ); 18 19 /* Filled in by udev-hid-bpf */ 20 char UDEV_PROP_HUION_FIRMWARE_ID[64]; 21 22 /* The prefix of the firmware ID we expect for this device. The full firmware 23 * string has a date suffix, e.g. HUION_T21j_221221 24 */ 25 char EXPECTED_FIRMWARE_ID[] = "HUION_T216_"; 26 27 /* How this BPF program works: the tablet has two modes, firmware mode and 28 * tablet mode. In firmware mode (out of the box) the tablet sends button events 29 * and the dial as keyboard combinations. In tablet mode it uses a vendor specific 30 * hid report to report everything instead. 31 * Depending on the mode some hid reports are never sent and the corresponding 32 * devices are mute. 33 * 34 * To switch the tablet use e.g. https://github.com/whot/huion-switcher 35 * or one of the tools from the digimend project 36 * 37 * This BPF works for both modes. The huion-switcher tool sets the 38 * HUION_FIRMWARE_ID udev property - if that is set then we disable the firmware 39 * pad and pen reports (by making them vendor collections that are ignored). 40 * If that property is not set we fix all hidraw nodes so the tablet works in 41 * either mode though the drawback is that the device will show up twice if 42 * you bind it to all event nodes 43 * 44 * Default report descriptor for the first exposed hidraw node: 45 * 46 * # HUION Huion Tablet_Q630M 47 * # 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 0 48 * # 0x09, 0x01, // Usage (Vendor Usage 1) 3 49 * # 0xa1, 0x01, // Collection (Application) 5 50 * # 0x85, 0x08, // Report ID (8) 7 51 * # 0x75, 0x58, // Report Size (88) 9 52 * # 0x95, 0x01, // Report Count (1) 11 53 * # 0x09, 0x01, // Usage (Vendor Usage 1) 13 54 * # 0x81, 0x02, // Input (Data,Var,Abs) 15 55 * # 0xc0, // End Collection 17 56 * R: 18 06 00 ff 09 01 a1 01 85 08 75 58 95 01 09 01 81 02 c0 57 * 58 * This rdesc does nothing until the tablet is switched to raw mode, see 59 * https://github.com/whot/huion-switcher 60 * 61 * 62 * Second hidraw node is the Pen. This one sends events until the tablet is 63 * switched to raw mode, then it's mute. 64 * 65 * # Report descriptor length: 93 bytes 66 * # HUION Huion Tablet_Q630M 67 * # 0x05, 0x0d, // Usage Page (Digitizers) 0 68 * # 0x09, 0x02, // Usage (Pen) 2 69 * # 0xa1, 0x01, // Collection (Application) 4 70 * # 0x85, 0x0a, // Report ID (10) 6 71 * # 0x09, 0x20, // Usage (Stylus) 8 72 * # 0xa1, 0x01, // Collection (Application) 10 73 * # 0x09, 0x42, // Usage (Tip Switch) 12 74 * # 0x09, 0x44, // Usage (Barrel Switch) 14 75 * # 0x09, 0x45, // Usage (Eraser) 16 76 * # 0x09, 0x3c, // Usage (Invert) 18 77 * # 0x15, 0x00, // Logical Minimum (0) 20 78 * # 0x25, 0x01, // Logical Maximum (1) 22 79 * # 0x75, 0x01, // Report Size (1) 24 80 * # 0x95, 0x06, // Report Count (6) 26 81 * # 0x81, 0x02, // Input (Data,Var,Abs) 28 82 * # 0x09, 0x32, // Usage (In Range) 30 83 * # 0x75, 0x01, // Report Size (1) 32 84 * # 0x95, 0x01, // Report Count (1) 34 85 * # 0x81, 0x02, // Input (Data,Var,Abs) 36 86 * # 0x81, 0x03, // Input (Cnst,Var,Abs) 38 87 * # 0x05, 0x01, // Usage Page (Generic Desktop) 40 88 * # 0x09, 0x30, // Usage (X) 42 89 * # 0x09, 0x31, // Usage (Y) 44 90 * # 0x55, 0x0d, // Unit Exponent (-3) 46 91 * # 0x65, 0x33, // Unit (EnglishLinear: in³) 48 92 * # 0x26, 0xff, 0x7f, // Logical Maximum (32767) 50 93 * # 0x35, 0x00, // Physical Minimum (0) 53 94 * # 0x46, 0x00, 0x08, // Physical Maximum (2048) 55 95 * # 0x75, 0x10, // Report Size (16) 58 96 * # 0x95, 0x02, // Report Count (2) 60 97 * # 0x81, 0x02, // Input (Data,Var,Abs) 62 98 * # 0x05, 0x0d, // Usage Page (Digitizers) 64 99 * # 0x09, 0x30, // Usage (Tip Pressure) 66 100 * # 0x26, 0xff, 0x1f, // Logical Maximum (8191) 68 101 * # 0x75, 0x10, // Report Size (16) 71 102 * # 0x95, 0x01, // Report Count (1) 73 103 * # 0x81, 0x02, // Input (Data,Var,Abs) 75 104 * # 0x09, 0x3d, // Usage (X Tilt) 77 105 * # 0x09, 0x3e, // Usage (Y Tilt) 79 106 * # 0x15, 0x81, // Logical Minimum (-127) 81 107 * # 0x25, 0x7f, // Logical Maximum (127) 83 108 * # 0x75, 0x08, // Report Size (8) 85 109 * # 0x95, 0x02, // Report Count (2) 87 110 * # 0x81, 0x02, // Input (Data,Var,Abs) 89 111 * # 0xc0, // End Collection 91 112 * # 0xc0, // End Collection 92 113 * R: 93 05 0d 09 02 a1 01 85 0a 09 20 a1 01 09 42 09 44 09 45 09 3c 15 00 25 01 75 01 95 06 81 02 09 32 75 01 95 01 81 02 81 03 05 01 09 30 09 31 55 0d 65 33 26 ff 7f 35 00 46 00 08 75 10 95 02 81 02 05 0d 09 30 26 ff 1f 75 10 95 01 81 02 09 3d 09 3e 15 81 25 7f 75 08 95 02 81 02 c0 c0 114 * 115 * Third hidraw node is the pad which sends a combination of keyboard shortcuts until 116 * the tablet is switched to raw mode, then it's mute: 117 * 118 * # Report descriptor length: 148 bytes 119 * # HUION Huion Tablet_Q630M 120 * # 0x05, 0x01, // Usage Page (Generic Desktop) 0 121 * # 0x09, 0x0e, // Usage (System Multi-Axis Controller) 2 122 * # 0xa1, 0x01, // Collection (Application) 4 123 * # 0x85, 0x11, // Report ID (17) 6 124 * # 0x05, 0x0d, // Usage Page (Digitizers) 8 125 * # 0x09, 0x21, // Usage (Puck) 10 126 * # 0xa1, 0x02, // Collection (Logical) 12 127 * # 0x15, 0x00, // Logical Minimum (0) 14 128 * # 0x25, 0x01, // Logical Maximum (1) 16 129 * # 0x75, 0x01, // Report Size (1) 18 130 * # 0x95, 0x01, // Report Count (1) 20 131 * # 0xa1, 0x00, // Collection (Physical) 22 132 * # 0x05, 0x09, // Usage Page (Button) 24 133 * # 0x09, 0x01, // Usage (Vendor Usage 0x01) 26 134 * # 0x81, 0x02, // Input (Data,Var,Abs) 28 135 * # 0x05, 0x0d, // Usage Page (Digitizers) 30 136 * # 0x09, 0x33, // Usage (Touch) 32 137 * # 0x81, 0x02, // Input (Data,Var,Abs) 34 138 * # 0x95, 0x06, // Report Count (6) 36 139 * # 0x81, 0x03, // Input (Cnst,Var,Abs) 38 140 * # 0xa1, 0x02, // Collection (Logical) 40 141 * # 0x05, 0x01, // Usage Page (Generic Desktop) 42 142 * # 0x09, 0x37, // Usage (Dial) 44 143 * # 0x16, 0x00, 0x80, // Logical Minimum (-32768) 46 144 * # 0x26, 0xff, 0x7f, // Logical Maximum (32767) 49 145 * # 0x75, 0x10, // Report Size (16) 52 146 * # 0x95, 0x01, // Report Count (1) 54 147 * # 0x81, 0x06, // Input (Data,Var,Rel) 56 148 * # 0x35, 0x00, // Physical Minimum (0) 58 149 * # 0x46, 0x10, 0x0e, // Physical Maximum (3600) 60 150 * # 0x15, 0x00, // Logical Minimum (0) 63 151 * # 0x26, 0x10, 0x0e, // Logical Maximum (3600) 65 152 * # 0x09, 0x48, // Usage (Resolution Multiplier) 68 153 * # 0xb1, 0x02, // Feature (Data,Var,Abs) 70 154 * # 0x45, 0x00, // Physical Maximum (0) 72 155 * # 0xc0, // End Collection 74 156 * # 0x75, 0x08, // Report Size (8) 75 157 * # 0x95, 0x01, // Report Count (1) 77 158 * # 0x81, 0x01, // Input (Cnst,Arr,Abs) 79 159 * # 0x75, 0x08, // Report Size (8) 81 160 * # 0x95, 0x01, // Report Count (1) 83 161 * # 0x81, 0x01, // Input (Cnst,Arr,Abs) 85 162 * # 0x75, 0x08, // Report Size (8) 87 163 * # 0x95, 0x01, // Report Count (1) 89 164 * # 0x81, 0x01, // Input (Cnst,Arr,Abs) 91 165 * # 0x75, 0x08, // Report Size (8) 93 166 * # 0x95, 0x01, // Report Count (1) 95 167 * # 0x81, 0x01, // Input (Cnst,Arr,Abs) 97 168 * # 0x75, 0x08, // Report Size (8) 99 169 * # 0x95, 0x01, // Report Count (1) 101 170 * # 0x81, 0x01, // Input (Cnst,Arr,Abs) 103 171 * # 0xc0, // End Collection 105 172 * # 0xc0, // End Collection 106 173 * # 0xc0, // End Collection 107 174 * # 0x05, 0x01, // Usage Page (Generic Desktop) 108 175 * # 0x09, 0x06, // Usage (Keyboard) 110 176 * # 0xa1, 0x01, // Collection (Application) 112 177 * # 0x85, 0x03, // Report ID (3) 114 178 * # 0x05, 0x07, // Usage Page (Keyboard) 116 179 * # 0x19, 0xe0, // Usage Minimum (224) 118 180 * # 0x29, 0xe7, // Usage Maximum (231) 120 181 * # 0x15, 0x00, // Logical Minimum (0) 122 182 * # 0x25, 0x01, // Logical Maximum (1) 124 183 * # 0x75, 0x01, // Report Size (1) 126 184 * # 0x95, 0x08, // Report Count (8) 128 185 * # 0x81, 0x02, // Input (Data,Var,Abs) 130 186 * # 0x05, 0x07, // Usage Page (Keyboard) 132 187 * # 0x19, 0x00, // Usage Minimum (0) 134 188 * # 0x29, 0xff, // Usage Maximum (255) 136 189 * # 0x26, 0xff, 0x00, // Logical Maximum (255) 138 190 * # 0x75, 0x08, // Report Size (8) 141 191 * # 0x95, 0x06, // Report Count (6) 143 192 * # 0x81, 0x00, // Input (Data,Arr,Abs) 145 193 * # 0xc0, // End Collection 147 194 * R: 148 05 01 09 0e a1 01 85 11 05 0d 09 21 a1 02 15 00 25 01 75 01 95 01 a1 00 05 09 09 01 81 02 05 0d 09 33 81 02 95 06 81 03 a1 02 05 01 09 37 16 00 80 26 ff 7f 75 10 95 01 81 06 35 00 46 10 0e 15 00 26 10 0e 09 48 b1 02 45 00 c0 75 08 95 01 81 01 75 08 95 01 81 01 75 08 95 01 81 01 75 08 95 01 81 01 75 08 95 01 81 01 c0 c0 c0 05 01 09 06 a1 01 85 03 05 07 19 e0 29 e7 15 00 25 01 75 01 95 08 81 02 05 07 19 00 29 ff 26 ff 00 75 08 95 06 81 00 c0 195 */ 196 197 #define PAD_REPORT_DESCRIPTOR_LENGTH 148 198 #define PEN_REPORT_DESCRIPTOR_LENGTH 93 199 #define VENDOR_REPORT_DESCRIPTOR_LENGTH 18 200 #define PAD_REPORT_ID 3 201 #define DIAL_REPORT_ID 17 202 #define PEN_REPORT_ID 10 203 #define VENDOR_REPORT_ID 8 204 #define PAD_REPORT_LENGTH 9 205 #define PEN_REPORT_LENGTH 10 206 #define VENDOR_REPORT_LENGTH 12 207 208 209 __u8 last_button_state; 210 211 static const __u8 fixed_rdesc_pad[] = { 212 UsagePage_GenericDesktop 213 Usage_GD_Keypad 214 CollectionApplication( 215 // -- Byte 0 in report 216 ReportId(PAD_REPORT_ID) 217 LogicalRange_i8(0, 1) 218 UsagePage_Digitizers 219 Usage_Dig_TabletFunctionKeys 220 CollectionPhysical( 221 // Byte 1 in report - just exists so we get to be a tablet pad 222 Usage_Dig_BarrelSwitch // BTN_STYLUS 223 ReportCount(1) 224 ReportSize(1) 225 Input(Var|Abs) 226 ReportCount(7) // padding 227 Input(Const) 228 // Bytes 2/3 in report - just exists so we get to be a tablet pad 229 UsagePage_GenericDesktop 230 Usage_GD_X 231 Usage_GD_Y 232 ReportCount(2) 233 ReportSize(8) 234 Input(Var|Abs) 235 // Byte 4 in report is the dial 236 Usage_GD_Wheel 237 LogicalRange_i8(-1, 1) 238 ReportCount(1) 239 ReportSize(8) 240 Input(Var|Rel) 241 // Byte 5 is the button state 242 UsagePage_Button 243 UsageRange_i8(0x01, 0x8) 244 LogicalRange_i8(0x0, 0x1) 245 ReportCount(7) 246 ReportSize(1) 247 Input(Var|Abs) 248 ReportCount(1) // padding 249 Input(Const) 250 ) 251 // Make sure we match our original report length 252 FixedSizeVendorReport(PAD_REPORT_LENGTH) 253 ) 254 }; 255 256 static const __u8 fixed_rdesc_pen[] = { 257 UsagePage_Digitizers 258 Usage_Dig_Pen 259 CollectionApplication( 260 // -- Byte 0 in report 261 ReportId(PEN_REPORT_ID) 262 Usage_Dig_Pen 263 CollectionPhysical( 264 // -- Byte 1 in report 265 Usage_Dig_TipSwitch 266 Usage_Dig_BarrelSwitch 267 Usage_Dig_SecondaryBarrelSwitch // maps eraser to BTN_STYLUS2 268 LogicalRange_i8(0, 1) 269 ReportSize(1) 270 ReportCount(3) 271 Input(Var|Abs) 272 ReportCount(4) // Padding 273 Input(Const) 274 Usage_Dig_InRange 275 ReportCount(1) 276 Input(Var|Abs) 277 ReportSize(16) 278 ReportCount(1) 279 PushPop( 280 UsagePage_GenericDesktop 281 Unit(cm) 282 UnitExponent(-1) 283 PhysicalRange_i16(0, 266) 284 LogicalRange_i16(0, 32767) 285 Usage_GD_X 286 Input(Var|Abs) // Bytes 2+3 287 PhysicalRange_i16(0, 166) 288 LogicalRange_i16(0, 32767) 289 Usage_GD_Y 290 Input(Var|Abs) // Bytes 4+5 291 ) 292 UsagePage_Digitizers 293 Usage_Dig_TipPressure 294 LogicalRange_i16(0, 8191) 295 Input(Var|Abs) // Byte 6+7 296 ReportSize(8) 297 ReportCount(2) 298 LogicalRange_i8(-60, 60) 299 Usage_Dig_XTilt 300 Usage_Dig_YTilt 301 Input(Var|Abs) // Byte 8+9 302 ) 303 ) 304 }; 305 306 static const __u8 fixed_rdesc_vendor[] = { 307 UsagePage_Digitizers 308 Usage_Dig_Pen 309 CollectionApplication( 310 // Byte 0 311 // We leave the pen on the vendor report ID 312 ReportId(VENDOR_REPORT_ID) 313 Usage_Dig_Pen 314 CollectionPhysical( 315 // Byte 1 are the buttons 316 LogicalRange_i8(0, 1) 317 ReportSize(1) 318 Usage_Dig_TipSwitch 319 Usage_Dig_BarrelSwitch 320 Usage_Dig_SecondaryBarrelSwitch 321 ReportCount(3) 322 Input(Var|Abs) 323 ReportCount(4) // Padding 324 Input(Const) 325 Usage_Dig_InRange 326 ReportCount(1) 327 Input(Var|Abs) 328 ReportSize(16) 329 ReportCount(1) 330 PushPop( 331 UsagePage_GenericDesktop 332 Unit(cm) 333 UnitExponent(-1) 334 // Note: reported logical range differs 335 // from the pen report ID for x and y 336 LogicalRange_i16(0, 53340) 337 PhysicalRange_i16(0, 266) 338 // Bytes 2/3 in report 339 Usage_GD_X 340 Input(Var|Abs) 341 LogicalRange_i16(0, 33340) 342 PhysicalRange_i16(0, 166) 343 // Bytes 4/5 in report 344 Usage_GD_Y 345 Input(Var|Abs) 346 ) 347 // Bytes 6/7 in report 348 LogicalRange_i16(0, 8191) 349 Usage_Dig_TipPressure 350 Input(Var|Abs) 351 // Bytes 8/9 in report 352 ReportCount(1) // Padding 353 Input(Const) 354 LogicalRange_i8(-60, 60) 355 // Byte 10 in report 356 Usage_Dig_XTilt 357 // Byte 11 in report 358 Usage_Dig_YTilt 359 ReportSize(8) 360 ReportCount(2) 361 Input(Var|Abs) 362 ) 363 ) 364 UsagePage_GenericDesktop 365 Usage_GD_Keypad 366 CollectionApplication( 367 // Byte 0 368 ReportId(PAD_REPORT_ID) 369 LogicalRange_i8(0, 1) 370 UsagePage_Digitizers 371 Usage_Dig_TabletFunctionKeys 372 CollectionPhysical( 373 // Byte 1 are the buttons 374 Usage_Dig_BarrelSwitch // BTN_STYLUS, needed so we get to be a tablet pad 375 ReportCount(1) 376 ReportSize(1) 377 Input(Var|Abs) 378 ReportCount(7) // Padding 379 Input(Const) 380 // Bytes 2/3 - x/y just exist so we get to be a tablet pad 381 UsagePage_GenericDesktop 382 Usage_GD_X 383 Usage_GD_Y 384 ReportCount(2) 385 ReportSize(8) 386 Input(Var|Abs) 387 // Byte 4 is the button state 388 UsagePage_Button 389 UsageRange_i8(0x01, 0x8) 390 LogicalRange_i8(0x0, 0x1) 391 ReportCount(8) 392 ReportSize(1) 393 Input(Var|Abs) 394 // Byte 5 is the top dial 395 UsagePage_GenericDesktop 396 Usage_GD_Wheel 397 LogicalRange_i8(-1, 1) 398 ReportCount(1) 399 ReportSize(8) 400 Input(Var|Rel) 401 // Byte 6 is the bottom dial 402 UsagePage_Consumer 403 Usage_Con_ACPan 404 Input(Var|Rel) 405 ) 406 // Make sure we match our original report length 407 FixedSizeVendorReport(VENDOR_REPORT_LENGTH) 408 ) 409 }; 410 411 static const __u8 disabled_rdesc_pen[] = { 412 FixedSizeVendorReport(PEN_REPORT_LENGTH) 413 }; 414 415 static const __u8 disabled_rdesc_pad[] = { 416 FixedSizeVendorReport(PAD_REPORT_LENGTH) 417 }; 418 419 SEC(HID_BPF_RDESC_FIXUP) 420 int BPF_PROG(dial_2_fix_rdesc, struct hid_bpf_ctx *hctx) 421 { 422 __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */); 423 __s32 rdesc_size = hctx->size; 424 __u8 have_fw_id; 425 426 if (!data) 427 return 0; /* EPERM check */ 428 429 /* If we have a firmware ID and it matches our expected prefix, we 430 * disable the default pad/pen nodes. They won't send events 431 * but cause duplicate devices. 432 */ 433 have_fw_id = __builtin_memcmp(UDEV_PROP_HUION_FIRMWARE_ID, 434 EXPECTED_FIRMWARE_ID, 435 sizeof(EXPECTED_FIRMWARE_ID) - 1) == 0; 436 if (rdesc_size == PAD_REPORT_DESCRIPTOR_LENGTH) { 437 if (have_fw_id) { 438 __builtin_memcpy(data, disabled_rdesc_pad, sizeof(disabled_rdesc_pad)); 439 return sizeof(disabled_rdesc_pad); 440 } 441 442 __builtin_memcpy(data, fixed_rdesc_pad, sizeof(fixed_rdesc_pad)); 443 return sizeof(fixed_rdesc_pad); 444 } 445 if (rdesc_size == PEN_REPORT_DESCRIPTOR_LENGTH) { 446 if (have_fw_id) { 447 __builtin_memcpy(data, disabled_rdesc_pen, sizeof(disabled_rdesc_pen)); 448 return sizeof(disabled_rdesc_pen); 449 } 450 451 __builtin_memcpy(data, fixed_rdesc_pen, sizeof(fixed_rdesc_pen)); 452 return sizeof(fixed_rdesc_pen); 453 } 454 /* Always fix the vendor mode so the tablet will work even if nothing sets 455 * the udev property (e.g. huion-switcher run manually) 456 */ 457 if (rdesc_size == VENDOR_REPORT_DESCRIPTOR_LENGTH) { 458 __builtin_memcpy(data, fixed_rdesc_vendor, sizeof(fixed_rdesc_vendor)); 459 return sizeof(fixed_rdesc_vendor); 460 461 } 462 return 0; 463 } 464 465 SEC(HID_BPF_DEVICE_EVENT) 466 int BPF_PROG(dial_2_fix_events, struct hid_bpf_ctx *hctx) 467 { 468 __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 16 /* size */); 469 static __u8 button; 470 471 if (!data) 472 return 0; /* EPERM check */ 473 474 /* Only sent if tablet is in default mode */ 475 if (data[0] == PAD_REPORT_ID) { 476 /* Nicely enough, this device only supports one button down at a time so 477 * the reports are easy to match. Buttons numbered from the top 478 * Button released: 03 00 00 00 00 00 00 00 479 * Button 1: 03 00 05 00 00 00 00 00 -> b 480 * Button 2: 03 00 08 00 00 00 00 00 -> e 481 * Button 3: 03 00 0c 00 00 00 00 00 -> i 482 * Button 4: 03 00 e0 16 00 00 00 00 -> Ctrl S 483 * Button 5: 03 00 2c 00 00 00 00 00 -> space 484 * Button 6: 03 00 e0 e2 1d 00 00 00 -> Ctrl Alt Z 485 */ 486 button &= 0xc0; 487 488 switch ((data[2] << 16) | (data[3] << 8) | data[4]) { 489 case 0x000000: 490 break; 491 case 0x050000: 492 button |= BIT(0); 493 break; 494 case 0x080000: 495 button |= BIT(1); 496 break; 497 case 0x0c0000: 498 button |= BIT(2); 499 break; 500 case 0xe01600: 501 button |= BIT(3); 502 break; 503 case 0x2c0000: 504 button |= BIT(4); 505 break; 506 case 0xe0e21d: 507 button |= BIT(5); 508 break; 509 } 510 511 __u8 report[8] = {PAD_REPORT_ID, 0x0, 0x0, 0x0, 0x00, button}; 512 513 __builtin_memcpy(data, report, sizeof(report)); 514 return sizeof(report); 515 } 516 517 /* Only sent if tablet is in default mode */ 518 if (data[0] == DIAL_REPORT_ID) { 519 /* 520 * In default mode, both dials are merged together: 521 * 522 * Dial down: 11 00 ff ff 00 00 00 00 00 -> Dial -1 523 * Dial up: 11 00 01 00 00 00 00 00 00 -> Dial 1 524 */ 525 __u16 dial = data[3] << 8 | data[2]; 526 527 button &= 0x3f; 528 button |= !!data[1] << 6; 529 530 __u8 report[] = {PAD_REPORT_ID, 0x0, 0x0, 0x0, dial, button}; 531 532 __builtin_memcpy(data, report, sizeof(report)); 533 return sizeof(report); 534 } 535 536 /* Nothing to do for the PEN_REPORT_ID, it's already mapped */ 537 538 /* Only sent if tablet is in raw mode */ 539 if (data[0] == VENDOR_REPORT_ID) { 540 /* Pad reports */ 541 if (data[1] & 0x20) { 542 /* See fixed_rdesc_pad */ 543 struct pad_report { 544 __u8 report_id; 545 __u8 btn_stylus; 546 __u8 x; 547 __u8 y; 548 __u8 buttons; 549 __u8 dial_1; 550 __u8 dial_2; 551 } __attribute__((packed)) *pad_report; 552 __u8 dial_1 = 0, dial_2 = 0; 553 554 /* Dial report */ 555 if (data[1] == 0xf1) { 556 __u8 d = 0; 557 558 if (data[5] == 2) 559 d = 0xff; 560 else 561 d = data[5]; 562 563 if (data[3] == 1) 564 dial_1 = d; 565 else 566 dial_2 = d; 567 } else { 568 /* data[4] are the buttons, mapped correctly */ 569 last_button_state = data[4]; 570 dial_1 = 0; // dial 571 dial_2 = 0; 572 } 573 574 pad_report = (struct pad_report *)data; 575 576 pad_report->report_id = PAD_REPORT_ID; 577 pad_report->btn_stylus = 0; 578 pad_report->x = 0; 579 pad_report->y = 0; 580 pad_report->buttons = last_button_state; 581 pad_report->dial_1 = dial_1; 582 pad_report->dial_2 = dial_2; 583 584 return sizeof(struct pad_report); 585 } 586 587 /* Pen reports need nothing done */ 588 } 589 590 return 0; 591 } 592 593 HID_BPF_OPS(inspiroy_dial2) = { 594 .hid_device_event = (void *)dial_2_fix_events, 595 .hid_rdesc_fixup = (void *)dial_2_fix_rdesc, 596 }; 597 598 SEC("syscall") 599 int probe(struct hid_bpf_probe_args *ctx) 600 { 601 switch (ctx->rdesc_size) { 602 case PAD_REPORT_DESCRIPTOR_LENGTH: 603 case PEN_REPORT_DESCRIPTOR_LENGTH: 604 case VENDOR_REPORT_DESCRIPTOR_LENGTH: 605 ctx->retval = 0; 606 break; 607 default: 608 ctx->retval = -EINVAL; 609 } 610 611 return 0; 612 } 613 614 char _license[] SEC("license") = "GPL"; 615