feat: add MIDI 2.0 Device class driver (USB-MIDI 2.0)

Add native USB-MIDI 2.0 Device class driver to TinyUSB. Implements the
USB-MIDI 2.0 specification with both Alt Setting 0 (MIDI 1.0 fallback)
and Alt Setting 1 (UMP native) descriptor support.

Driver features:
- UMP (Universal MIDI Packet) read/write with atomic message framing
- Protocol negotiation: Endpoint Discovery, Config Request/Notify,
  Function Block Discovery (embedded in driver)
- Group Terminal Block descriptor via GET_DESCRIPTOR
- Alt Setting switch handler with endpoint re-arm
- Static allocation, no dynamic memory, ISR-safe

Build system:
- Register midi2d_* in usbd.c driver table
- Add TUD_MIDI2_DESCRIPTOR macros to usbd.h
- Add config defaults (CFG_TUD_MIDI2_*) to tusb_option.h
- Add midi2_ump_word_count() to midi.h (shared by Device and Host)
- Add midi2_device.c/h to family.cmake and CMakeLists.txt
- Add midi2_device.h include to tusb.h

All changes guarded by #if CFG_TUD_MIDI2 (default 0). Zero impact on
existing drivers and examples.

Tested: Raspberry Pi Pico (RP2040), Linux ALSA, Windows MIDI Services

1 files changed, 52 insertions, 0 deletions

diff --git a/src/tusb_option.h b/src/tusb_option.h
index 154f8e2a4..4483c2200 100644
--- a/src/tusb_option.h
+++ b/src/tusb_option.h
@@ -646,6 +646,42 @@
   #define CFG_TUD_MIDI            0
 #endif
 
+#ifndef CFG_TUD_MIDI2
+  #define CFG_TUD_MIDI2           0
+#endif
+
+#ifndef CFG_TUD_MIDI2_TX_BUFSIZE
+  #define CFG_TUD_MIDI2_TX_BUFSIZE  256
+#endif
+
+#ifndef CFG_TUD_MIDI2_RX_BUFSIZE
+  #define CFG_TUD_MIDI2_RX_BUFSIZE  256
+#endif
+
+#ifndef CFG_TUD_MIDI2_TX_EPSIZE
+  #define CFG_TUD_MIDI2_TX_EPSIZE   64
+#endif
+
+#ifndef CFG_TUD_MIDI2_RX_EPSIZE
+  #define CFG_TUD_MIDI2_RX_EPSIZE   64
+#endif
+
+#ifndef CFG_TUD_MIDI2_NUM_GROUPS
+  #define CFG_TUD_MIDI2_NUM_GROUPS  1
+#endif
+
+#ifndef CFG_TUD_MIDI2_NUM_FUNCTION_BLOCKS
+  #define CFG_TUD_MIDI2_NUM_FUNCTION_BLOCKS 1
+#endif
+
+#ifndef CFG_TUD_MIDI2_EP_NAME
+  #define CFG_TUD_MIDI2_EP_NAME     "TinyUSB MIDI 2.0"
+#endif
+
+#ifndef CFG_TUD_MIDI2_PRODUCT_ID
+  #define CFG_TUD_MIDI2_PRODUCT_ID  "TinyUSB-MIDI2"
+#endif
+
 #ifndef CFG_TUD_VENDOR
   #define CFG_TUD_VENDOR          0
 #endif
@@ -815,6 +851,22 @@
   #define CFG_TUH_MIDI   0
 #endif
 
+#ifndef CFG_TUH_MIDI2
+  #define CFG_TUH_MIDI2  0
+#endif
+
+#ifndef CFG_TUH_MIDI2_RX_BUFSIZE
+  #define CFG_TUH_MIDI2_RX_BUFSIZE (4 * TUH_EPSIZE_BULK_MAX)
+#endif
+
+#ifndef CFG_TUH_MIDI2_TX_BUFSIZE
+  #define CFG_TUH_MIDI2_TX_BUFSIZE (4 * TUH_EPSIZE_BULK_MAX)
+#endif
+
+#ifndef CFG_TUH_MIDI2_LOG_LEVEL
+  #define CFG_TUH_MIDI2_LOG_LEVEL CFG_TUH_LOG_LEVEL
+#endif
+
 #ifndef CFG_TUH_MSC
   #define CFG_TUH_MSC    0
 #endif