/* This function will add a function to a configuration. */
rt_err_t rt_usbd_config_add_function(uconfig_t cfg, ufunction_t func)
/* This function will add a function to a configuration. */
rt_err_t rt_usbd_config_add_function(uconfig_t cfg, ufunction_t func)
{
    LOG_D("rt_usbd_config_add_function");
    RT_ASSERT(cfg != RT_NULL);
    RT_ASSERT(func != RT_NULL);
    rt_list_insert_before(&cfg->func_list, &func->list);
    return RT_EOK;
}