1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  HID driver for Gembird Joypad, "PC Game Controller"
4 *
5 *  Copyright (c) 2015 Red Hat, Inc
6 *  Copyright (c) 2015 Benjamin Tissoires
7 */
8
9/*
10 */
11
12#include <linux/device.h>
13#include <linux/hid.h>
14#include <linux/module.h>
15
16#include "hid-ids.h"
17
18#define GEMBIRD_START_FAULTY_RDESC	8
19
20static const __u8 gembird_jpd_faulty_rdesc[] = {
21	0x75, 0x08,			/*   Report Size (8)		*/
22	0x95, 0x05,			/*   Report Count (5)		*/
23	0x15, 0x00,			/*   Logical Minimum (0)	*/
24	0x26, 0xff, 0x00,		/*   Logical Maximum (255)	*/
25	0x35, 0x00,			/*   Physical Minimum (0)	*/
26	0x46, 0xff, 0x00,		/*   Physical Maximum (255)	*/
27	0x09, 0x30,			/*   Usage (X)			*/
28	0x09, 0x31,			/*   Usage (Y)			*/
29	0x09, 0x32,			/*   Usage (Z)			*/
30	0x09, 0x32,			/*   Usage (Z)			*/
31	0x09, 0x35,			/*   Usage (Rz)			*/
32	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
33};
34
35/*
36 * we fix the report descriptor by:
37 * - marking the first Z axis as constant (so it is ignored by HID)
38 * - assign the original second Z to Rx
39 * - assign the original Rz to Ry
40 */
41static const __u8 gembird_jpd_fixed_rdesc[] = {
42	0x75, 0x08,			/*   Report Size (8)		*/
43	0x95, 0x02,			/*   Report Count (2)		*/
44	0x15, 0x00,			/*   Logical Minimum (0)	*/
45	0x26, 0xff, 0x00,		/*   Logical Maximum (255)	*/
46	0x35, 0x00,			/*   Physical Minimum (0)	*/
47	0x46, 0xff, 0x00,		/*   Physical Maximum (255)	*/
48	0x09, 0x30,			/*   Usage (X)			*/
49	0x09, 0x31,			/*   Usage (Y)			*/
50	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
51	0x95, 0x01,			/*   Report Count (1)		*/
52	0x09, 0x32,			/*   Usage (Z)			*/
53	0x81, 0x01,			/*   Input (Cnst,Arr,Abs)	*/
54	0x95, 0x02,			/*   Report Count (2)		*/
55	0x09, 0x33,			/*   Usage (Rx)			*/
56	0x09, 0x34,			/*   Usage (Ry)			*/
57	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
58};
59
60static __u8 *gembird_report_fixup(struct hid_device *hdev, __u8 *rdesc,
61		unsigned int *rsize)
62{
63	__u8 *new_rdesc;
64	/* delta_size is > 0 */
65	size_t delta_size = sizeof(gembird_jpd_fixed_rdesc) -
66			    sizeof(gembird_jpd_faulty_rdesc);
67	size_t new_size = *rsize + delta_size;
68
69	if (*rsize >= 31 && !memcmp(&rdesc[GEMBIRD_START_FAULTY_RDESC],
70				    gembird_jpd_faulty_rdesc,
71				    sizeof(gembird_jpd_faulty_rdesc))) {
72		new_rdesc = devm_kzalloc(&hdev->dev, new_size, GFP_KERNEL);
73		if (new_rdesc == NULL)
74			return rdesc;
75
76		dev_info(&hdev->dev,
77			 "fixing Gembird JPD-DualForce 2 report descriptor.\n");
78
79		/* start by copying the end of the rdesc */
80		memcpy(new_rdesc + delta_size, rdesc, *rsize);
81
82		/* add the correct beginning */
83		memcpy(new_rdesc, rdesc, GEMBIRD_START_FAULTY_RDESC);
84
85		/* replace the faulty part with the fixed one */
86		memcpy(new_rdesc + GEMBIRD_START_FAULTY_RDESC,
87		       gembird_jpd_fixed_rdesc,
88		       sizeof(gembird_jpd_fixed_rdesc));
89
90		*rsize = new_size;
91		rdesc = new_rdesc;
92	}
93
94	return rdesc;
95}
96
97static const struct hid_device_id gembird_devices[] = {
98	{ HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
99			 USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
100	{ }
101};
102MODULE_DEVICE_TABLE(hid, gembird_devices);
103
104static struct hid_driver gembird_driver = {
105	.name = "gembird",
106	.id_table = gembird_devices,
107	.report_fixup = gembird_report_fixup,
108};
109module_hid_driver(gembird_driver);
110
111MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
112MODULE_DESCRIPTION("HID Gembird joypad driver");
113MODULE_LICENSE("GPL");
114