LXR linux/drivers/hid/hid-elecom.c

   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
  38static 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
  53static __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
  80static 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};
  91MODULE_DEVICE_TABLE(hid, elecom_devices);
  92
  93static struct hid_driver elecom_driver = {
  94        .name = "elecom",
  95        .id_table = elecom_devices,
  96        .report_fixup = elecom_report_fixup
  97};
  98module_hid_driver(elecom_driver);
  99
 100MODULE_LICENSE("GPL");
 101