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 */
15
16 /*
17 */
18
19 #include <linux/device.h>
20 #include <linux/hid.h>
21 #include <linux/module.h>
22
23 #include "hid-ids.h"
24
25 /*
26 * Certain ELECOM mice misreport their button count meaning that they only work
27 * correctly with the ELECOM mouse assistant software which is unavailable for
28 * Linux. A four extra INPUT reports and a FEATURE report are described by the
29 * report descriptor but it does not appear that these enable software to
30 * control what the extra buttons map to. The only simple and straightforward
31 * solution seems to involve fixing up the report descriptor.
32 *
33 * Report descriptor format:
34 * Positions 13, 15, 21 and 31 store the button bit count, button usage minimum,
35 * button usage maximum and padding bit count respectively.
36 */
37 #define MOUSE_BUTTONS_MAX 8
mouse_button_fixup(struct hid_device * hdev,__u8 * rdesc,unsigned int rsize,int nbuttons)38 static void mouse_button_fixup(struct hid_device *hdev,
39 __u8 *rdesc, unsigned int rsize,
40 int nbuttons)
41 {
42 if (rsize < 32 || rdesc[12] != 0x95 ||
43 rdesc[14] != 0x75 || rdesc[15] != 0x01 ||
44 rdesc[20] != 0x29 || rdesc[30] != 0x75)
45 return;
46 hid_info(hdev, "Fixing up Elecom mouse button count\n");
47 nbuttons = clamp(nbuttons, 0, MOUSE_BUTTONS_MAX);
48 rdesc[13] = nbuttons;
49 rdesc[21] = nbuttons;
50 rdesc[31] = MOUSE_BUTTONS_MAX - nbuttons;
51 }
52
elecom_report_fixup(struct hid_device * hdev,__u8 * rdesc,unsigned int * rsize)53 static __u8 *elecom_report_fixup(struct hid_device *hdev, __u8 *rdesc,
54 unsigned int *rsize)
55 {
56 switch (hdev->product) {
57 case USB_DEVICE_ID_ELECOM_BM084:
58 /* The BM084 Bluetooth mouse includes a non-existing horizontal
59 * wheel in the HID descriptor. */
60 if (*rsize >= 48 && rdesc[46] == 0x05 && rdesc[47] == 0x0c) {
61 hid_info(hdev, "Fixing up Elecom BM084 report descriptor\n");
62 rdesc[47] = 0x00;
63 }
64 break;
65 case USB_DEVICE_ID_ELECOM_M_XT3URBK:
66 case USB_DEVICE_ID_ELECOM_M_XT3DRBK:
67 case USB_DEVICE_ID_ELECOM_M_XT4DRBK:
68 mouse_button_fixup(hdev, rdesc, *rsize, 6);
69 break;
70 case USB_DEVICE_ID_ELECOM_M_DT1URBK:
71 case USB_DEVICE_ID_ELECOM_M_DT1DRBK:
72 case USB_DEVICE_ID_ELECOM_M_HT1URBK:
73 case USB_DEVICE_ID_ELECOM_M_HT1DRBK:
74 mouse_button_fixup(hdev, rdesc, *rsize, 8);
75 break;
76 }
77 return rdesc;
78 }
79
80 static const struct hid_device_id elecom_devices[] = {
81 { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
82 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT3URBK) },
83 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT3DRBK) },
84 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_XT4DRBK) },
85 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_DT1URBK) },
86 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_DT1DRBK) },
87 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_HT1URBK) },
88 { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_M_HT1DRBK) },
89 { }
90 };
91 MODULE_DEVICE_TABLE(hid, elecom_devices);
92
93 static struct hid_driver elecom_driver = {
94 .name = "elecom",
95 .id_table = elecom_devices,
96 .report_fixup = elecom_report_fixup
97 };
98 module_hid_driver(elecom_driver);
99
100 MODULE_LICENSE("GPL");
101