xref: /linux/drivers/hid/hid-redragon.c (revision 9e56ff53b4115875667760445b028357848b4748)
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");
63