root/drivers/hid/hid-elecom.c

DEFINITIONS

1. mouse_button_fixup
2. elecom_report_fixup

   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
  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 
  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");