usb_descriptors.c

/**
 * Copyright (c) 2022 Nicolai Electronics
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * SPDX-License-Identifier: MIT
 */

#include "usb_descriptors.h"

#include "bsp/board.h"
#include "pico/unique_id.h"
#include "tusb.h"

// String descriptors

char const* string_desc_arr[] = {
    (const char[]){0x09, 0x04},  // 0: is supported language is English (0x0409)
    "Nicolai Electronics",       // 1: Manufacturer
    "I2C adapter",               // 2: Product
    "I2C interface",             // 3: I2C (vendor) interface
    //"Debug"                      // 4: Debug (cdc) interface
};

enum {
    STRING_DESC = 0,
    STRING_DESC_MANUFACTURER,
    STRING_DESC_PRODUCT,
    STRING_DESC_VENDOR_0,
    // STRING_DESC_CDC_0,
    STRING_DESC_SERIAL  // (Not in the string description array)
};

static uint16_t _desc_str[32];

uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
    (void) langid;
    uint8_t chr_count;
    if (index == STRING_DESC) {
        memcpy(&_desc_str[1], string_desc_arr[0], 2);
        chr_count = 1;
    } else if (index == STRING_DESC_SERIAL) {
        pico_unique_board_id_t id;
        pico_get_unique_board_id(&id);
        const uint8_t* str = id.id;
        chr_count          = 16;
        for (uint8_t len = 0; len < chr_count; ++len) {
            uint8_t c = str[len >> 1];
            c         = ((c >> (((len & 1) ^ 1) << 2)) & 0x0F) + '0';
            if (c > '9') {
                c += 7;
            }
            _desc_str[1 + len] = c;
        }
    } else {
        // Convert ASCII string into UTF-16
        if (!(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0]))) {
            return NULL;
        }
        const char* str = string_desc_arr[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;
}

// Device descriptors

tusb_desc_device_t const desc_device = {
    .bLength            = sizeof(tusb_desc_device_t),
    .bDescriptorType    = TUSB_DESC_DEVICE,
    .bcdUSB             = 0x0210,  // Supported USB standard (2.1)
    .bDeviceClass       = TUSB_CLASS_MISC,
    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,    // Endpoint 0 packet size
    .idVendor           = 0x1c40,                    // Vendor identifier
    .idProduct          = 0x0534,                    // Product identifier
    .bcdDevice          = 0x0100,                    // Protocol version
    .iManufacturer      = STRING_DESC_MANUFACTURER,  // Index of manufacturer name string
    .iProduct           = STRING_DESC_PRODUCT,       // Index of product name string
    .iSerialNumber      = STRING_DESC_SERIAL,        // Index of serial number string
    .bNumConfigurations = 0x01                       // Number of configurations supported
};

uint8_t const* tud_descriptor_device_cb(void) { return (uint8_t const*) &desc_device; }

// Configuration Descriptor

#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + CFG_TUD_CDC * TUD_CDC_DESC_LEN + CFG_TUD_VENDOR * TUD_VENDOR_DESC_LEN)

#define EPNUM_VENDOR_0_OUT 0x01  // Endpoint 1
#define EPNUM_VENDOR_0_IN  0x81

/*#define EPNUM_CDC_0_NOTIF 0x82  // Endpoint 2: CDC serial port for ESP32 console, control
#define EPNUM_CDC_0_OUT   0x03  // Endpoint 3: CDC serial port for ESP32 console, data
#define EPNUM_CDC_0_IN    0x83*/

uint8_t const desc_fs_configuration[] = {
    // Config number, interface count, string index, total length, attribute, power in mA
    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),

    // WebUSB: Interface number, string index, EP Out & IN address, EP size
    TUD_VENDOR_DESCRIPTOR(ITF_NUM_VENDOR_0, STRING_DESC_VENDOR_0, EPNUM_VENDOR_0_OUT, EPNUM_VENDOR_0_IN, 32),

    // CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
    // TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_0, STRING_DESC_CDC_0, EPNUM_CDC_0_NOTIF, 8, EPNUM_CDC_0_OUT, EPNUM_CDC_0_IN, 64),
};

uint8_t const* tud_descriptor_configuration_cb(uint8_t index) {
    (void) index;
    return desc_fs_configuration;
}