From a2e4b957ca314f4b206421ef792df0a55a947394 Mon Sep 17 00:00:00 2001
From: Pieter Pas <pieter.pas@outlook.com>
Date: Thu, 4 Jan 2024 22:52:46 +0100
Subject: [PATCH] ESP32S3 USB MIDI support

---
 src/MIDI_Interfaces/USBMIDI/USBMIDI.hpp       | 22 ++++++++++++
 src/MIDI_Interfaces/USBMIDI/USBMIDI_ESP32.hpp | 36 +++++++++++++++++++
 src/MIDI_Interfaces/USBMIDI_Interface.hpp     |  4 +--
 3 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 src/MIDI_Interfaces/USBMIDI/USBMIDI_ESP32.hpp

diff --git a/src/MIDI_Interfaces/USBMIDI/USBMIDI.hpp b/src/MIDI_Interfaces/USBMIDI/USBMIDI.hpp
index c2f34444b3..b560f4f5a4 100644
--- a/src/MIDI_Interfaces/USBMIDI/USBMIDI.hpp
+++ b/src/MIDI_Interfaces/USBMIDI/USBMIDI.hpp
@@ -4,6 +4,11 @@
 #include <AH/STL/cstdint>
 #include <Settings/NamespaceSettings.hpp>
 
+#ifdef ARDUINO_ARCH_ESP32
+#include <esp_arduino_version.h>
+#include <sdkconfig.h>
+#endif
+
 BEGIN_CS_NAMESPACE
 
 inline AH::Array<uint8_t, 4> u32_to_bytes(uint32_t u) {
@@ -72,6 +77,23 @@ using USBDeviceMIDIBackend = MIDIUSB_USBDeviceMIDIBackend;
 END_CS_NAMESPACE
 #endif
 
+#elif defined(ARDUINO_ARCH_ESP32) && (ESP_ARDUINO_VERSION_MAJOR >= 3) &&       \
+    CONFIG_IDF_TARGET_ESP32S3
+
+#ifndef ARDUINO_USB_MODE
+#error "ESP32S3 expects ARDUINO_USB_MODE to be set"
+#endif
+#if ARDUINO_USB_MODE != 1
+#include "USBMIDI_ESP32.hpp"
+BEGIN_CS_NAMESPACE
+using USBDeviceMIDIBackend = ESP32_USBDeviceMIDIBackend;
+END_CS_NAMESPACE
+#else
+#define CS_USB_MIDI_NOT_SUPPORTED
+#pragma message(                                                               \
+    "ESP32S3: USB MIDI not enabled. Set the Tools > USB Type setting to \"USB-OTG\" to enable it.")
+#endif
+
 #elif defined(ARDUINO_ARCH_MBED_RP2040)
 
 #include "USBMIDI_RP2040.hpp"
diff --git a/src/MIDI_Interfaces/USBMIDI/USBMIDI_ESP32.hpp b/src/MIDI_Interfaces/USBMIDI/USBMIDI_ESP32.hpp
new file mode 100644
index 0000000000..453bf6ff66
--- /dev/null
+++ b/src/MIDI_Interfaces/USBMIDI/USBMIDI_ESP32.hpp
@@ -0,0 +1,36 @@
+#include <AH/Containers/Array.hpp>
+#include <Settings/NamespaceSettings.hpp>
+
+#include <USB.h>
+#include <USBMIDI.h>
+
+BEGIN_CS_NAMESPACE
+
+struct ESP32_USBDeviceMIDIBackend {
+    /// USB MIDI packages are 4 bytes.
+    using MIDIUSBPacket_t = AH::Array<uint8_t, 4>;
+    /// Called once upon initialization.
+    void begin() {
+        backend.begin();
+        USB.begin();
+    }
+    /// Read a single packet. Return a packet of all zeros if there is no packet.
+    MIDIUSBPacket_t read() {
+        midiEventPacket_t packet {0, 0, 0, 0};
+        backend.readPacket(&packet);
+        return {packet.header, packet.byte1, packet.byte2, packet.byte3};
+    }
+    /// Write a single packet to the output buffer.
+    void write(MIDIUSBPacket_t p) {
+        midiEventPacket_t packet {p[0], p[1], p[2], p[3]};
+        backend.writePacket(&packet);
+    }
+    /// Transmit the output buffer immediately (not implemented).
+    void sendNow() {}
+    /// No explicit call to sendNow is required.
+    bool preferImmediateSend() { return false; }
+    /// The actual low-level USB MIDI backend provided by the core libraries.
+    USBMIDI backend;
+};
+
+END_CS_NAMESPACE
\ No newline at end of file
diff --git a/src/MIDI_Interfaces/USBMIDI_Interface.hpp b/src/MIDI_Interfaces/USBMIDI_Interface.hpp
index 732d5c0367..06bfc31268 100644
--- a/src/MIDI_Interfaces/USBMIDI_Interface.hpp
+++ b/src/MIDI_Interfaces/USBMIDI_Interface.hpp
@@ -118,8 +118,8 @@ END_CS_NAMESPACE
 #include "USBMIDI_Interface.ipp"
 
 #if defined(TEENSYDUINO) && !defined(TEENSY_MIDIUSB_ENABLED)
-#warning                                                                       \
-    "Teensy: USB MIDI not enabled. Enable it from the Tools > USB Type menu."
+#pragma message(                                                               \
+    "Teensy: USB MIDI not enabled. Enable it from the Tools > USB Type menu.")
 #define CS_USB_MIDI_DISABLED
 #endif