drivers/hid/hid-gembird.c

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