deskhop/src/usb.c

/* 
 * This file is part of DeskHop (https://github.com/hrvach/deskhop).
 * Copyright (c) 2024 Hrvoje Cavrak
 * 
 * This program is free software: you can redistribute it and/or modify  
 * it under the terms of the GNU General Public License as published by  
 * the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "main.h"

/**================================================== *
 * ===========  TinyUSB Device Callbacks  =========== *
 * ================================================== */

/* Invoked when we get GET_REPORT control request. 
 * We are expected to fill buffer with the report content, update reqlen 
 * and return its length. We return 0 to STALL the request. */
uint16_t tud_hid_get_report_cb(uint8_t instance,
                               uint8_t report_id,
                               hid_report_type_t report_type,
                               uint8_t* buffer,
                               uint16_t reqlen) {
    return 0;
}

/**
 * Computer controls our LEDs by sending USB SetReport messages with a payload
 * of just 1 byte and report type output. It's type 0x21 (USB_REQ_DIR_OUT |
 * USB_REQ_TYP_CLASS | USB_REQ_REC_IFACE) Request code for SetReport is 0x09,
 * report type is 0x02 (HID_REPORT_TYPE_OUTPUT). We get a set_report callback
 * from TinyUSB device HID and then figure out what to do with the LEDs.
 */
void tud_hid_set_report_cb(uint8_t instance,
                           uint8_t report_id,
                           hid_report_type_t report_type,
                           uint8_t const* buffer,
                           uint16_t bufsize) {
    if (report_id == REPORT_ID_KEYBOARD && bufsize == 1 && report_type == HID_REPORT_TYPE_OUTPUT) {
        /**
         * If we are using caps lock LED to indicate the chosen output, we will
         * override whatever is sent through the SetReport message.
         */
        uint8_t leds = buffer[0];

        if (KBD_LED_AS_INDICATOR) {
            leds = leds & 0xFD;  /* 1111 1101 (Clear Caps Lock bit) */

            if (global_state.active_output)
                leds |= KEYBOARD_LED_CAPSLOCK;
        }

        global_state.keyboard_leds[global_state.active_output] = leds;

        /* If we are board without the keyboard hooked up directly, we need to send this information 
           to the other one since that one has the keyboard connected to it (and LEDs you can turn on :)) */           
        if (global_state.keyboard_connected)
            restore_leds(&global_state);
        else
            send_value(leds, KBD_SET_REPORT_MSG);
    }
}

/* Invoked when device is mounted */
void tud_mount_cb(void) {
    global_state.tud_connected = true;
}

/* Invoked when device is unmounted */
void tud_umount_cb(void) {
    global_state.tud_connected = false;
}

/**================================================== *
 * ===============  USB HOST Section  =============== *
 * ================================================== */

void tuh_hid_umount_cb(uint8_t dev_addr, uint8_t instance) {
    uint8_t const itf_protocol = tuh_hid_interface_protocol(dev_addr, instance);
    switch (itf_protocol) {
        case HID_ITF_PROTOCOL_KEYBOARD:
            global_state.keyboard_connected = false;
            break;

        case HID_ITF_PROTOCOL_MOUSE:
            global_state.mouse_connected = false;

            /* Clear this so reconnecting a mouse doesn't try to continue in HID REPORT protocol */
            memset(&global_state.mouse_dev, 0, sizeof(global_state.mouse_dev));            
            break;
    }
}
    
void tuh_hid_mount_cb(uint8_t dev_addr,
                      uint8_t instance,
                      uint8_t const* desc_report,
                      uint16_t desc_len) {
    uint8_t const itf_protocol = tuh_hid_interface_protocol(dev_addr, instance);      

    switch (itf_protocol) {
        case HID_ITF_PROTOCOL_KEYBOARD:
            /* Keeping this is needed for setting leds from device set_report callback */
            global_state.kbd_dev_addr = dev_addr;
            global_state.kbd_instance = instance;
            global_state.keyboard_connected = true;        
            break;

        case HID_ITF_PROTOCOL_MOUSE:
            /* Switch to using protocol report instead of boot report, it's more complicated but
               at least we get all the information we need (looking at you, mouse wheel) */
            if (tuh_hid_get_protocol(dev_addr, instance) == HID_PROTOCOL_BOOT) {
                tuh_hid_set_protocol(dev_addr, instance, HID_PROTOCOL_REPORT);
            }
            parse_report_descriptor(&global_state.mouse_dev, MAX_REPORTS, desc_report, desc_len);

            global_state.mouse_connected = true;           
            break;
    }
    /* Flash local led to indicate a device was connected */
    blink_led(&global_state);           

    /* Also signal the other board to flash LED, to enable easy verification if serial works */
    send_value(ENABLE, FLASH_LED_MSG);


    /* Kick off the report querying */
    tuh_hid_receive_report(dev_addr, instance);
}

/* Invoked when received report from device via interrupt endpoint */
void tuh_hid_report_received_cb(uint8_t dev_addr,
                                uint8_t instance,
                                uint8_t const* report,
                                uint16_t len) {
    (void)len;
    uint8_t const itf_protocol = tuh_hid_interface_protocol(dev_addr, instance);

    switch (itf_protocol) {
        case HID_ITF_PROTOCOL_KEYBOARD:
            process_keyboard_report((uint8_t*)report, len, &global_state);
            break;

        case HID_ITF_PROTOCOL_MOUSE:
            process_mouse_report((uint8_t*)report, len, &global_state);
            break;
    }

    /* Continue requesting reports */
    tuh_hid_receive_report(dev_addr, instance);
}

/* Set protocol in a callback. If we were called, command succeeded. We're only
   doing this for the mouse anyway, so we can only be called about the mouse */
void tuh_hid_set_protocol_complete_cb(uint8_t dev_addr, uint8_t idx, uint8_t protocol) {
    (void) dev_addr;
    (void) idx;
    global_state.mouse_dev.protocol = protocol;
}