1 // SPDX-License-Identifier: GPL-2.0-only
19 /* Filled in by udev-hid-bpf */
28  * tablet mode. In firmware mode (out of the box) the tablet sends button events
34  * To switch the tablet use e.g.  https://github.com/whot/huion-switcher
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
49  * # 0xa1, 0x01,                    // Collection (Application)            5
59  * https://github.com/whot/huion-switcher
90  * # 0x55, 0x0d,                    //   Unit Exponent (-3)                46
106  * # 0x15, 0x81,                    //   Logical Minimum (-127)            81
121  * # 0x09, 0x0e,                    // Usage (System Multi-Axis Controller) 2
132  * # 0x05, 0x09,                    //    Usage Page (Button)              24
143  * # 0x16, 0x00, 0x80,              //     Logical Minimum (-32768)        46
215 		// -- Byte 0 in report
222 			// Byte 1 in report - just exists so we get to be a tablet pad
229 			// Bytes 2/3 in report - just exists so we get to be a tablet pad
238 			LogicalMinimum_i8(-1)
243 			// Byte 5 is the button state
264 		// -- Byte 0 in report
268 			// -- Byte 1 in report
287 				UnitExponent(-1)
299 				Input(Var|Abs) // Bytes 4+5
308 			LogicalMinimum_i8(-60)
345 				UnitExponent(-1)
359 				// Bytes 4/5 in report
371 			LogicalMinimum_i8(-60)
399 			// Bytes 2/3 - x/y just exist so we get to be a tablet pad
406 			// Byte 4 is the button state
415 			// Byte 5 is the top dial
418 			LogicalMinimum_i8(-1)
445 	__s32 rdesc_size = hctx->size;  in SEC()
457 				      sizeof(EXPECTED_FIRMWARE_ID) - 1) == 0;  in SEC()
477 	 * the udev property (e.g. huion-switcher run manually)  in SEC()
491 	static __u8 button;  in SEC()  local
498 		/* Nicely enough, this device only supports one button down at a time so  in SEC()
500 		 *   Button released: 03 00 00 00 00 00 00 00  in SEC()
501 		 *   Button 1: 03 00 05 00 00 00 00 00 -> b  in SEC()
502 		 *   Button 2: 03 00 08 00 00 00 00 00 -> e  in SEC()
503 		 *   Button 3: 03 00 0c 00 00 00 00 00 -> i  in SEC()
504 		 *   Button 4: 03 00 e0 16 00 00 00 00 -> Ctrl S  in SEC()
505 		 *   Button 5: 03 00 2c 00 00 00 00 00 -> space  in SEC()
506 		 *   Button 6: 03 00 e0 e2 1d 00 00 00 -> Ctrl Alt Z  in SEC()
508 		button &= 0xc0;  in SEC()
514 			button |= BIT(0);  in SEC()
517 			button |= BIT(1);  in SEC()
520 			button |= BIT(2);  in SEC()
523 			button |= BIT(3);  in SEC()
526 			button |= BIT(4);  in SEC()
529 			button |= BIT(5);  in SEC()
533 		__u8 report[8] = {PAD_REPORT_ID, 0x0, 0x0, 0x0, 0x00, button};  in SEC()
544 		 *   Dial down: 11 00 ff ff 00 00 00 00 00 -> Dial -1  in SEC()
545 		 *   Dial up:   11 00 01 00 00 00 00 00 00 -> Dial 1  in SEC()
549 		button &= 0x3f;  in SEC()
550 		button |= !!data[1] << 6;  in SEC()
552 		__u8 report[] = {PAD_REPORT_ID, 0x0, 0x0, 0x0, dial, button};  in SEC()
580 				if (data[5] == 2)  in SEC()
583 					d = data[5];  in SEC()
598 			pad_report->report_id = PAD_REPORT_ID;  in SEC()
599 			pad_report->btn_stylus = 0;  in SEC()
600 			pad_report->x = 0;  in SEC()
601 			pad_report->y = 0;  in SEC()
602 			pad_report->buttons = last_button_state;  in SEC()
603 			pad_report->dial_1 = dial_1;  in SEC()
604 			pad_report->dial_2 = dial_2;  in SEC()
623 	switch (ctx->rdesc_size) {  in probe()
627 		ctx->retval = 0;  in probe()
630 		ctx->retval = -EINVAL;  in probe()