1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * HID driver for PhoenixRC 8-axis flight controller
4 *
5 * Copyright (C) 2022 Marcus Folkesson <marcus.folkesson@gmail.com>
6 */
7
8#include <linux/device.h>
9#include <linux/hid.h>
10#include <linux/module.h>
11
12#include "hid-ids.h"
13
14struct pxrc_priv {
15	u8 slider;
16	u8 dial;
17	bool alternate;
18};
19
20static __u8 pxrc_rdesc_fixed[] = {
21	0x05, 0x01,        // Usage Page (Generic Desktop Ctrls)
22	0x09, 0x04,        // Usage (Joystick)
23	0xA1, 0x01,        // Collection (Application)
24	0x09, 0x01,        //   Usage (Pointer)
25	0xA1, 0x00,        //   Collection (Physical)
26	0x09, 0x30,        //     Usage (X)
27	0x09, 0x36,        //     Usage (Slider)
28	0x09, 0x31,        //     Usage (Y)
29	0x09, 0x32,        //     Usage (Z)
30	0x09, 0x33,        //     Usage (Rx)
31	0x09, 0x34,        //     Usage (Ry)
32	0x09, 0x35,        //     Usage (Rz)
33	0x09, 0x37,        //     Usage (Dial)
34	0x15, 0x00,        //     Logical Minimum (0)
35	0x26, 0xFF, 0x00,  //     Logical Maximum (255)
36	0x35, 0x00,        //     Physical Minimum (0)
37	0x46, 0xFF, 0x00,  //     Physical Maximum (255)
38	0x75, 0x08,        //     Report Size (8)
39	0x95, 0x08,        //     Report Count (8)
40	0x81, 0x02,        //     Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
41	0xC0,              //   End Collection
42	0xC0,              // End Collection
43};
44
45static __u8 *pxrc_report_fixup(struct hid_device *hdev, __u8 *rdesc,
46				unsigned int *rsize)
47{
48	hid_info(hdev, "fixing up PXRC report descriptor\n");
49	*rsize = sizeof(pxrc_rdesc_fixed);
50	return pxrc_rdesc_fixed;
51}
52
53static int pxrc_raw_event(struct hid_device *hdev, struct hid_report *report,
54	 u8 *data, int size)
55{
56	struct pxrc_priv *priv = hid_get_drvdata(hdev);
57
58	if (priv->alternate)
59		priv->slider = data[7];
60	else
61		priv->dial = data[7];
62
63	data[1] = priv->slider;
64	data[7] = priv->dial;
65
66	priv->alternate = !priv->alternate;
67	return 0;
68}
69
70static int pxrc_probe(struct hid_device *hdev, const struct hid_device_id *id)
71{
72	int ret;
73	struct pxrc_priv *priv;
74
75	priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
76	if (!priv)
77		return -ENOMEM;
78	hid_set_drvdata(hdev, priv);
79
80	ret = hid_parse(hdev);
81	if (ret) {
82		hid_err(hdev, "parse failed\n");
83		return ret;
84	}
85
86	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
87	if (ret) {
88		hid_err(hdev, "hw start failed\n");
89		return ret;
90	}
91
92	return 0;
93}
94
95static const struct hid_device_id pxrc_devices[] = {
96	{ HID_USB_DEVICE(USB_VENDOR_ID_MULTIPLE_1781, USB_DEVICE_ID_PHOENIXRC) },
97	{ /* sentinel */ }
98};
99MODULE_DEVICE_TABLE(hid, pxrc_devices);
100
101static struct hid_driver pxrc_driver = {
102	.name = "hid-pxrc",
103	.id_table = pxrc_devices,
104	.report_fixup = pxrc_report_fixup,
105	.probe = pxrc_probe,
106	.raw_event = pxrc_raw_event,
107};
108module_hid_driver(pxrc_driver);
109
110MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
111MODULE_DESCRIPTION("HID driver for PXRC 8-axis flight controller");
112MODULE_LICENSE("GPL");
113