drivers/hid/hid-gembird.c

   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
  20 static 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  */
  41 static 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
  60 static __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
  97 static const struct hid_device_id gembird_devices[] = {
  98         { HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
  99                          USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
 100         { }
 101 };
 102 MODULE_DEVICE_TABLE(hid, gembird_devices);
 103
 104 static struct hid_driver gembird_driver = {
 105         .name = "gembird",
 106         .id_table = gembird_devices,
 107         .report_fixup = gembird_report_fixup,
 108 };
 109 module_hid_driver(gembird_driver);
 110
 111 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
 112 MODULE_DESCRIPTION("HID Gembird joypad driver");
 113 MODULE_LICENSE("GPL");