1/*
2 *  HID driver for Gembird Joypad, "PC Game Controller"
3 *
4 *  Copyright (c) 2015 Red Hat, Inc
5 *  Copyright (c) 2015 Benjamin Tissoires
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#define GEMBIRD_START_FAULTY_RDESC	8
22
23static const __u8 gembird_jpd_faulty_rdesc[] = {
24	0x75, 0x08,			/*   Report Size (8)		*/
25	0x95, 0x05,			/*   Report Count (5)		*/
26	0x15, 0x00,			/*   Logical Minimum (0)	*/
27	0x26, 0xff, 0x00,		/*   Logical Maximum (255)	*/
28	0x35, 0x00,			/*   Physical Minimum (0)	*/
29	0x46, 0xff, 0x00,		/*   Physical Maximum (255)	*/
30	0x09, 0x30,			/*   Usage (X)			*/
31	0x09, 0x31,			/*   Usage (Y)			*/
32	0x09, 0x32,			/*   Usage (Z)			*/
33	0x09, 0x32,			/*   Usage (Z)			*/
34	0x09, 0x35,			/*   Usage (Rz)			*/
35	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
36};
37
38/*
39 * we fix the report descriptor by:
40 * - marking the first Z axis as constant (so it is ignored by HID)
41 * - assign the original second Z to Rx
42 * - assign the original Rz to Ry
43 */
44static const __u8 gembird_jpd_fixed_rdesc[] = {
45	0x75, 0x08,			/*   Report Size (8)		*/
46	0x95, 0x02,			/*   Report Count (2)		*/
47	0x15, 0x00,			/*   Logical Minimum (0)	*/
48	0x26, 0xff, 0x00,		/*   Logical Maximum (255)	*/
49	0x35, 0x00,			/*   Physical Minimum (0)	*/
50	0x46, 0xff, 0x00,		/*   Physical Maximum (255)	*/
51	0x09, 0x30,			/*   Usage (X)			*/
52	0x09, 0x31,			/*   Usage (Y)			*/
53	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
54	0x95, 0x01,			/*   Report Count (1)		*/
55	0x09, 0x32,			/*   Usage (Z)			*/
56	0x81, 0x01,			/*   Input (Cnst,Arr,Abs)	*/
57	0x95, 0x02,			/*   Report Count (2)		*/
58	0x09, 0x33,			/*   Usage (Rx)			*/
59	0x09, 0x34,			/*   Usage (Ry)			*/
60	0x81, 0x02,			/*   Input (Data,Var,Abs)	*/
61};
62
63static __u8 *gembird_report_fixup(struct hid_device *hdev, __u8 *rdesc,
64		unsigned int *rsize)
65{
66	__u8 *new_rdesc;
67	/* delta_size is > 0 */
68	size_t delta_size = sizeof(gembird_jpd_fixed_rdesc) -
69			    sizeof(gembird_jpd_faulty_rdesc);
70	size_t new_size = *rsize + delta_size;
71
72	if (*rsize >= 31 && !memcmp(&rdesc[GEMBIRD_START_FAULTY_RDESC],
73				    gembird_jpd_faulty_rdesc,
74				    sizeof(gembird_jpd_faulty_rdesc))) {
75		new_rdesc = devm_kzalloc(&hdev->dev, new_size, GFP_KERNEL);
76		if (new_rdesc == NULL)
77			return rdesc;
78
79		dev_info(&hdev->dev,
80			 "fixing Gembird JPD-DualForce 2 report descriptor.\n");
81
82		/* start by copying the end of the rdesc */
83		memcpy(new_rdesc + delta_size, rdesc, *rsize);
84
85		/* add the correct beginning */
86		memcpy(new_rdesc, rdesc, GEMBIRD_START_FAULTY_RDESC);
87
88		/* replace the faulty part with the fixed one */
89		memcpy(new_rdesc + GEMBIRD_START_FAULTY_RDESC,
90		       gembird_jpd_fixed_rdesc,
91		       sizeof(gembird_jpd_fixed_rdesc));
92
93		*rsize = new_size;
94		rdesc = new_rdesc;
95	}
96
97	return rdesc;
98}
99
100static const struct hid_device_id gembird_devices[] = {
101	{ HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
102			 USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
103	{ }
104};
105MODULE_DEVICE_TABLE(hid, gembird_devices);
106
107static struct hid_driver gembird_driver = {
108	.name = "gembird",
109	.id_table = gembird_devices,
110	.report_fixup = gembird_report_fixup,
111};
112module_hid_driver(gembird_driver);
113
114MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
115MODULE_DESCRIPTION("HID Gembird joypad driver");
116MODULE_LICENSE("GPL");
117