drivers/hid/hid-pxrc.c

   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
  14 struct pxrc_priv {
  15         u8 slider;
  16         u8 dial;
  17         bool alternate;
  18 };
  19
  20 static const __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
  45 static const __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
  53 static 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
  70 static 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
  95 static const struct hid_device_id pxrc_devices[] = {
  96         { HID_USB_DEVICE(USB_VENDOR_ID_MULTIPLE_1781, USB_DEVICE_ID_PHOENIXRC) },
  97         { /* sentinel */ }
  98 };
  99 MODULE_DEVICE_TABLE(hid, pxrc_devices);
 100
 101 static 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 };
 108 module_hid_driver(pxrc_driver);
 109
 110 MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
 111 MODULE_DESCRIPTION("HID driver for PXRC 8-axis flight controller");
 112 MODULE_LICENSE("GPL");