usb_descriptors.c

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include "descriptor_xinput.h"
#include "tusb.h"


/* A combination of interfaces must have a unique product id, since PC will save
 * device driver after the first plug. Same VID/PID with different interface e.g
 * MSC (first), then CDC (later) will possibly cause system error on PC.
 *
 * Auto ProductID layout's Bitmap:
 *   [MSB]         HID | MSC | CDC          [LSB]
 */
#define _PID_MAP(itf, n) ((CFG_TUD_##itf) << (n))

// Invoked when received GET DEVICE DESCRIPTOR
// Application return pointer to descriptor
uint8_t const *tud_descriptor_device_cb(void) {
    return (uint8_t const *)&xinputDeviceDescriptor;
}

//--------------------------------------------------------------------+
// HID Report Descriptor
//--------------------------------------------------------------------+

// Invoked when received GET HID REPORT DESCRIPTOR
// Application return pointer to descriptor
// Descriptor contents must exist long enough for transfer to complete
uint8_t const *tud_hid_descriptor_report_cb(void) { 
  return 0;
}

//--------------------------------------------------------------------+
// Configuration Descriptor
//--------------------------------------------------------------------+



// Invoked when received GET CONFIGURATION DESCRIPTOR
// Application return pointer to descriptor
// Descriptor contents must exist long enough for transfer to complete
uint8_t const *tud_descriptor_configuration_cb(uint8_t index) {
  (void)index; // for multiple configurations
    return xinputConfigurationDescriptor;
  return 0;
}
//--------------------------------------------------------------------+
// String Descriptors
//--------------------------------------------------------------------+

static uint16_t _desc_str[32];

// Invoked when received GET STRING DESCRIPTOR request
// Application return pointer to descriptor, whose contents must exist long
// enough for transfer to complete
uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
  
      (void)langid;

        uint8_t chr_count;

        if (index == 0) {
          memcpy(&_desc_str[1], string_desc_arr_xinput[0], 2);
          chr_count = 1;
        } else {
          // Convert ASCII string into UTF-16

          if (!(index < sizeof(string_desc_arr_xinput) / sizeof(string_desc_arr_xinput[0])))
            return NULL;

          const char *str = string_desc_arr_xinput[index];

          // Cap at max char
          chr_count = strlen(str);
          if (chr_count > 31)
            chr_count = 31;

          for (uint8_t i = 0; i < chr_count; i++) {
            _desc_str[1 + i] = str[i];
          }
        }

        // first byte is length (including header), second byte is string type
        _desc_str[0] = (TUSB_DESC_STRING << 8) | (2 * chr_count + 2);

        return _desc_str;
  
 
}