1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * HID driver for ELECOM devices:
4 * - BM084 Bluetooth Mouse
5 * - EX-G Trackballs (M-XT3DRBK, M-XT3URBK, M-XT4DRBK)
6 * - DEFT Trackballs (M-DT1DRBK, M-DT1URBK, M-DT2DRBK, M-DT2URBK)
7 * - HUGE Trackballs (M-HT1DRBK, M-HT1URBK)
8 *
9 * Copyright (c) 2010 Richard Nauber <Richard.Nauber@gmail.com>
10 * Copyright (c) 2016 Yuxuan Shui <yshuiv7@gmail.com>
11 * Copyright (c) 2017 Diego Elio Pettenò <flameeyes@flameeyes.eu>
12 * Copyright (c) 2017 Alex Manoussakis <amanou@gnu.org>
13 * Copyright (c) 2017 Tomasz Kramkowski <tk@the-tk.com>
14 * Copyright (c) 2020 YOSHIOKA Takuma <lo48576@hard-wi.red>
15 * Copyright (c) 2022 Takahiro Fujii <fujii@xaxxi.net>
16 */
17
18/*
19 */
20
21#include <linux/device.h>
22#include <linux/hid.h>
23#include <linux/module.h>
24
25#include "hid-ids.h"
26
27/*
28 * Certain ELECOM mice misreport their button count meaning that they only work
29 * correctly with the ELECOM mouse assistant software which is unavailable for
30 * Linux. A four extra INPUT reports and a FEATURE report are described by the
31 * report descriptor but it does not appear that these enable software to
32 * control what the extra buttons map to. The only simple and straightforward
33 * solution seems to involve fixing up the report descriptor.
34 */
35#define MOUSE_BUTTONS_MAX 8
36static void mouse_button_fixup(struct hid_device *hdev,
37 __u8 *rdesc, unsigned int rsize,
38 unsigned int button_bit_count,
39 unsigned int padding_bit,
40 unsigned int button_report_size,
41 unsigned int button_usage_maximum,
42 int nbuttons)
43{
44 if (rsize < 32 || rdesc[button_bit_count] != 0x95 ||
45 rdesc[button_report_size] != 0x75 ||
46 rdesc[button_report_size + 1] != 0x01 ||
47 rdesc[button_usage_maximum] != 0x29 || rdesc[padding_bit] != 0x75)
48 return;
49 hid_info(hdev, "Fixing up Elecom mouse button count\n");
50 nbuttons = clamp(nbuttons, 0, MOUSE_BUTTONS_MAX);
51 rdesc[button_bit_count + 1] = nbuttons;
52 rdesc[button_usage_maximum + 1] = nbuttons;
53 rdesc[padding_bit + 1] = MOUSE_BUTTONS_MAX - nbuttons;
54}
55
56static __u8 *elecom_report_fixup(struct hid_device *hdev, __u8 *rdesc,
57 unsigned int *rsize)
58{
59 switch (hdev->product) {
60 case USB_DEVICE_ID_ELECOM_BM084:
61 /* The BM084 Bluetooth mouse includes a non-existing horizontal
62 * wheel in the HID descriptor. */
63 if (*rsize >= 48 && rdesc[46] == 0x05 && rdesc[47] == 0x0c) {
64 hid_info(hdev, "Fixing up Elecom BM084 report descriptor\n");
65 rdesc[47] = 0x00;
66 }
67 break;
68 case USB_DEVICE_ID_ELECOM_M_XGL20DLBK:
69 /*
70 * Report descriptor format:
71 * 20: button bit count
72 * 28: padding bit count
73 * 22: button report size
74 * 14: button usage maximum
75 */
76 mouse_button_fixup(hdev, rdesc, rsize: *rsize, button_bit_count: 20, padding_bit: 28, button_report_size: 22, button_usage_maximum: 14, nbuttons: 8);
77 break;
78 case USB_DEVICE_ID_ELECOM_M_XT3URBK:
79 case USB_DEVICE_ID_ELECOM_M_XT3DRBK:
80 case USB_DEVICE_ID_ELECOM_M_XT4DRBK:
81 /*
82 * Report descriptor format:
83 * 12: button bit count
84 * 30: padding bit count
85 * 14: button report size
86 * 20: button usage maximum
87 */
88 mouse_button_fixup(hdev, rdesc, rsize: *rsize, button_bit_count: 12, padding_bit: 30, button_report_size: 14, button_usage_maximum: 20, nbuttons: 6);
89 break;
90 case USB_DEVICE_ID_ELECOM_M_DT1URBK:
91 case USB_DEVICE_ID_ELECOM_M_DT1DRBK:
92 case USB_DEVICE_ID_ELECOM_M_HT1URBK:
93 case USB_DEVICE_ID_ELECOM_M_HT1DRBK_010D:
94 /*
95 * Report descriptor format:
96 * 12: button bit count
97 * 30: padding bit count
98 * 14: button report size
99 * 20: button usage maximum
100 */
101 mouse_button_fixup(hdev, rdesc, rsize: *rsize, button_bit_count: 12, padding_bit: 30, button_report_size: 14, button_usage_maximum: 20, nbuttons: 8);
102 break;
103 case USB_DEVICE_ID_ELECOM_M_HT1DRBK_011C:
104 /*
105 * Report descriptor format:
106 * 22: button bit count
107 * 30: padding bit count
108 * 24: button report size
109 * 16: button usage maximum
110 */
111 mouse_button_fixup(hdev, rdesc, rsize: *rsize, button_bit_count: 22, padding_bit: 30, button_report_size: 24, button_usage_maximum: 16, nbuttons: 8);
112 break;
113 }
114 return rdesc;
115}
116
117static const struct hid_device_id elecom_devices[] = {
118 { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
119 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XGL20DLBK) },
120 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT3URBK) },
121 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT3DRBK) },
122 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT4DRBK) },
123 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_DT1URBK) },
124 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_DT1DRBK) },
125 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_HT1URBK) },
126 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_HT1DRBK_010D) },
127 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_HT1DRBK_011C) },
128 { }
129};
130MODULE_DEVICE_TABLE(hid, elecom_devices);
131
132static struct hid_driver elecom_driver = {
133 .name = "elecom",
134 .id_table = elecom_devices,
135 .report_fixup = elecom_report_fixup
136};
137module_hid_driver(elecom_driver);
138
139MODULE_LICENSE("GPL");
140

source code of linux/drivers/hid/hid-elecom.c