drivers/hid/hid-redragon.c

   1 /*
   2  *  HID driver for Redragon keyboards
   3  *
   4  *  Copyright (c) 2017 Robert Munteanu
   5  *  SPDX-License-Identifier: GPL-2.0+
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  */
  14
  15 #include <linux/device.h>
  16 #include <linux/hid.h>
  17 #include <linux/module.h>
  18
  19 #include "hid-ids.h"
  20
  21
  22 /*
  23  * The Redragon Asura keyboard sends an incorrect HID descriptor.
  24  * At byte 100 it contains
  25  *
  26  *   0x81, 0x00
  27  *
  28  * which is Input (Data, Arr, Abs), but it should be
  29  *
  30  *   0x81, 0x02
  31  *
  32  * which is Input (Data, Var, Abs), which is consistent with the way
  33  * key codes are generated.
  34  */
  35
  36 static __u8 *redragon_report_fixup(struct hid_device *hdev, __u8 *rdesc,
  37         unsigned int *rsize)
  38 {
  39         if (*rsize >= 102 && rdesc[100] == 0x81 && rdesc[101] == 0x00) {
  40                 dev_info(&hdev->dev, "Fixing Redragon ASURA report descriptor.\n");
  41                 rdesc[101] = 0x02;
  42         }
  43
  44         return rdesc;
  45 }
  46
  47 static const struct hid_device_id redragon_devices[] = {
  48         {HID_USB_DEVICE(USB_VENDOR_ID_JESS, USB_DEVICE_ID_REDRAGON_ASURA)},
  49         {}
  50 };
  51
  52 MODULE_DEVICE_TABLE(hid, redragon_devices);
  53
  54 static struct hid_driver redragon_driver = {
  55         .name = "redragon",
  56         .id_table = redragon_devices,
  57         .report_fixup = redragon_report_fixup
  58 };
  59
  60 module_hid_driver(redragon_driver);
  61
  62 MODULE_LICENSE("GPL");