drivers/hid/hid-elecom.c

   1 /*
   2  *  HID driver for ELECOM devices:
   3  *  - BM084 Bluetooth Mouse
   4  *  - EX-G Trackball (Wired and wireless)
   5  *  - DEFT Trackball (Wired and wireless)
   6  *  - HUGE Trackball (Wired and wireless)
   7  *
   8  *  Copyright (c) 2010 Richard Nauber <Richard.Nauber@gmail.com>
   9  *  Copyright (c) 2016 Yuxuan Shui <yshuiv7@gmail.com>
  10  *  Copyright (c) 2017 Diego Elio Pettenò <flameeyes@flameeyes.eu>
  11  *  Copyright (c) 2017 Alex Manoussakis <amanou@gnu.org>
  12  *  Copyright (c) 2017 Tomasz Kramkowski <tk@the-tk.com>
  13  */
  14
  15 /*
  16  * This program is free software; you can redistribute it and/or modify it
  17  * under the terms of the GNU General Public License as published by the Free
  18  * Software Foundation; either version 2 of the License, or (at your option)
  19  * any later version.
  20  */
  21
  22 #include <linux/device.h>
  23 #include <linux/hid.h>
  24 #include <linux/module.h>
  25
  26 #include "hid-ids.h"
  27
  28 /*
  29  * Certain ELECOM mice misreport their button count meaning that they only work
  30  * correctly with the ELECOM mouse assistant software which is unavailable for
  31  * Linux. A four extra INPUT reports and a FEATURE report are described by the
  32  * report descriptor but it does not appear that these enable software to
  33  * control what the extra buttons map to. The only simple and straightforward
  34  * solution seems to involve fixing up the report descriptor.
  35  *
  36  * Report descriptor format:
  37  * Positions 13, 15, 21 and 31 store the button bit count, button usage minimum,
  38  * button usage maximum and padding bit count respectively.
  39  */
  40 #define MOUSE_BUTTONS_MAX 8
  41 static void mouse_button_fixup(struct hid_device *hdev,
  42                                __u8 *rdesc, unsigned int rsize,
  43                                int nbuttons)
  44 {
  45         if (rsize < 32 || rdesc[12] != 0x95 ||
  46             rdesc[14] != 0x75 || rdesc[15] != 0x01 ||
  47             rdesc[20] != 0x29 || rdesc[30] != 0x75)
  48                 return;
  49         hid_info(hdev, "Fixing up Elecom mouse button count\n");
  50         nbuttons = clamp(nbuttons, 0, MOUSE_BUTTONS_MAX);
  51         rdesc[13] = nbuttons;
  52         rdesc[21] = nbuttons;
  53         rdesc[31] = MOUSE_BUTTONS_MAX - nbuttons;
  54 }
  55
  56 static __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_EX_G_WIRED:
  69         case USB_DEVICE_ID_ELECOM_EX_G_WIRELESS:
  70                 mouse_button_fixup(hdev, rdesc, *rsize, 6);
  71                 break;
  72         case USB_DEVICE_ID_ELECOM_DEFT_WIRED:
  73         case USB_DEVICE_ID_ELECOM_DEFT_WIRELESS:
  74         case USB_DEVICE_ID_ELECOM_HUGE_WIRED:
  75         case USB_DEVICE_ID_ELECOM_HUGE_WIRELESS:
  76                 mouse_button_fixup(hdev, rdesc, *rsize, 8);
  77                 break;
  78         }
  79         return rdesc;
  80 }
  81
  82 static const struct hid_device_id elecom_devices[] = {
  83         { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
  84         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_EX_G_WIRED) },
  85         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_EX_G_WIRELESS) },
  86         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_DEFT_WIRED) },
  87         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_DEFT_WIRELESS) },
  88         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_HUGE_WIRED) },
  89         { HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_HUGE_WIRELESS) },
  90         { }
  91 };
  92 MODULE_DEVICE_TABLE(hid, elecom_devices);
  93
  94 static struct hid_driver elecom_driver = {
  95         .name = "elecom",
  96         .id_table = elecom_devices,
  97         .report_fixup = elecom_report_fixup
  98 };
  99 module_hid_driver(elecom_driver);
 100
 101 MODULE_LICENSE("GPL");