Support multiple USB MIDI inputs at once

* Maximum 2 inputs on Raspberry Pi 1-3
* Maximum 4 inputs on Raspberry Pi 4

src/config.h

@@ -32,6 +32,12 @@ class CConfig		// Configuration for MiniDexed
 public:
 	static const unsigned MaxNotes = 16;		// polyphony
 
+#if RASPPI <= 3
+	static const unsigned MaxUSBMIDIDevices = 2;
+#else
+	static const unsigned MaxUSBMIDIDevices = 4;
+#endif
+
 	static const unsigned LCDColumns = 16;		// HD44780 LCD
 	static const unsigned LCDRows = 2;
 

src/midikeyboard.cpp

@@ -24,18 +24,31 @@
 #include <circle/devicenameservice.h>
 #include <assert.h>
 
-CMIDIKeyboard *CMIDIKeyboard::s_pThis = 0;
+CMIDIKeyboard *CMIDIKeyboard::s_pThis[MaxInstances] = {0};
 
-CMIDIKeyboard::CMIDIKeyboard (CMiniDexed *pSynthesizer, CConfig *pConfig)
+TMIDIPacketHandler * const CMIDIKeyboard::s_pMIDIPacketHandler[MaxInstances] =
+{
+	MIDIPacketHandler0,
+	MIDIPacketHandler1,
+	MIDIPacketHandler2,
+	MIDIPacketHandler3
+};
+
+CMIDIKeyboard::CMIDIKeyboard (CMiniDexed *pSynthesizer, CConfig *pConfig, unsigned nInstance)
 :	CMIDIDevice (pSynthesizer, pConfig),
+	m_nInstance (nInstance),
 	m_pMIDIDevice (0)
 {
-	s_pThis = this;
+	assert (m_nInstance < MaxInstances);
+	s_pThis[m_nInstance] = this;
+
+	m_DeviceName.Format ("umidi%u", nInstance+1);
 }
 
 CMIDIKeyboard::~CMIDIKeyboard (void)
 {
-	s_pThis = 0;
+	assert (m_nInstance < MaxInstances);
+	s_pThis[m_nInstance] = 0;
 }
 
 void CMIDIKeyboard::Process (boolean bPlugAndPlayUpdated)
@@ -48,24 +61,45 @@ void CMIDIKeyboard::Process (boolean bPlugAndPlayUpdated)
 	if (m_pMIDIDevice == 0)
 	{
 		m_pMIDIDevice =
-			(CUSBMIDIDevice *) CDeviceNameService::Get ()->GetDevice ("umidi1", FALSE);
+			(CUSBMIDIDevice *) CDeviceNameService::Get ()->GetDevice (m_DeviceName, FALSE);
 		if (m_pMIDIDevice != 0)
 		{
-			m_pMIDIDevice->RegisterPacketHandler (MIDIPacketHandler);
+			assert (m_nInstance < MaxInstances);
+			m_pMIDIDevice->RegisterPacketHandler (s_pMIDIPacketHandler[m_nInstance]);
 
-			m_pMIDIDevice->RegisterRemovedHandler (DeviceRemovedHandler);
+			m_pMIDIDevice->RegisterRemovedHandler (DeviceRemovedHandler, this);
 		}
 	}
 }
 
-void CMIDIKeyboard::MIDIPacketHandler (unsigned nCable, u8 *pPacket, unsigned nLength)
+void CMIDIKeyboard::MIDIPacketHandler0 (unsigned nCable, u8 *pPacket, unsigned nLength)
 {
-	assert (s_pThis != 0);
-	s_pThis->MIDIMessageHandler (pPacket, nLength, nCable);
+	assert (s_pThis[0] != 0);
+	s_pThis[0]->MIDIMessageHandler (pPacket, nLength, nCable);
+}
+
+void CMIDIKeyboard::MIDIPacketHandler1 (unsigned nCable, u8 *pPacket, unsigned nLength)
+{
+	assert (s_pThis[1] != 0);
+	s_pThis[1]->MIDIMessageHandler (pPacket, nLength, nCable);
+}
+
+void CMIDIKeyboard::MIDIPacketHandler2 (unsigned nCable, u8 *pPacket, unsigned nLength)
+{
+	assert (s_pThis[2] != 0);
+	s_pThis[2]->MIDIMessageHandler (pPacket, nLength, nCable);
+}
+
+void CMIDIKeyboard::MIDIPacketHandler3 (unsigned nCable, u8 *pPacket, unsigned nLength)
+{
+	assert (s_pThis[3] != 0);
+	s_pThis[3]->MIDIMessageHandler (pPacket, nLength, nCable);
 }
 
 void CMIDIKeyboard::DeviceRemovedHandler (CDevice *pDevice, void *pContext)
 {
-	assert (s_pThis != 0);
-	s_pThis->m_pMIDIDevice = 0;
+	CMIDIKeyboard *pThis = static_cast<CMIDIKeyboard *> (pContext);
+	assert (pThis != 0);
+
+	pThis->m_pMIDIDevice = 0;
 }

src/midikeyboard.h

@@ -27,6 +27,7 @@
 #include "config.h"
 #include <circle/usb/usbmidi.h>
 #include <circle/device.h>
+#include <circle/string.h>
 #include <circle/types.h>
 
 class CMiniDexed;
@@ -34,20 +35,31 @@ class CMiniDexed;
 class CMIDIKeyboard : public CMIDIDevice
 {
 public:
-	CMIDIKeyboard (CMiniDexed *pSynthesizer, CConfig *pConfig);
+	static const unsigned MaxInstances = 4;
+
+public:
+	CMIDIKeyboard (CMiniDexed *pSynthesizer, CConfig *pConfig, unsigned nInstance = 0);
 	~CMIDIKeyboard (void);
 
 	void Process (boolean bPlugAndPlayUpdated);
 
 private:
-	static void MIDIPacketHandler (unsigned nCable, u8 *pPacket, unsigned nLength);
+	static void MIDIPacketHandler0 (unsigned nCable, u8 *pPacket, unsigned nLength);
+	static void MIDIPacketHandler1 (unsigned nCable, u8 *pPacket, unsigned nLength);
+	static void MIDIPacketHandler2 (unsigned nCable, u8 *pPacket, unsigned nLength);
+	static void MIDIPacketHandler3 (unsigned nCable, u8 *pPacket, unsigned nLength);
 
 	static void DeviceRemovedHandler (CDevice *pDevice, void *pContext);
 
 private:
+	unsigned m_nInstance;
+	CString m_DeviceName;
+
 	CUSBMIDIDevice * volatile m_pMIDIDevice;
 
-	static CMIDIKeyboard *s_pThis;
+	static CMIDIKeyboard *s_pThis[MaxInstances];
+
+	static TMIDIPacketHandler * const s_pMIDIPacketHandler[MaxInstances];
 };
 
 #endif

src/minidexed.cpp

@@ -28,7 +28,6 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt)
 :	CDexedAdapter (CConfig::MaxNotes, pConfig->GetSampleRate ()),
 	m_pConfig (pConfig),
 	m_UI (this, pConfig),
-	m_MIDIKeyboard (this, pConfig),
 	m_PCKeyboard (this),
 	m_SerialMIDI (this, pInterrupt, pConfig),
 	m_bUseSerial (false),
@@ -36,6 +35,11 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt)
 			 1000000U * pConfig->GetChunkSize ()/2 / pConfig->GetSampleRate ()),
 	m_bProfileEnabled (m_pConfig->GetProfileEnabled ())
 {
+	for (unsigned i = 0; i < CConfig::MaxUSBMIDIDevices; i++)
+	{
+		m_pMIDIKeyboard[i] = new CMIDIKeyboard (this, pConfig, i);
+		assert (m_pMIDIKeyboard[i]);
+	}
 };
 
 bool CMiniDexed::Initialize (void)
@@ -64,7 +68,11 @@ bool CMiniDexed::Initialize (void)
 
 void CMiniDexed::Process (bool bPlugAndPlayUpdated)
 {
-	m_MIDIKeyboard.Process (bPlugAndPlayUpdated);
+	for (unsigned i = 0; i < CConfig::MaxUSBMIDIDevices; i++)
+	{
+		assert (m_pMIDIKeyboard[i]);
+		m_pMIDIKeyboard[i]->Process (bPlugAndPlayUpdated);
+	}
 
 	m_PCKeyboard.Process (bPlugAndPlayUpdated);
 

src/minidexed.h

@@ -54,7 +54,7 @@ private:
 	CUserInterface m_UI;
 	CSysExFileLoader m_SysExFileLoader;
 
-	CMIDIKeyboard m_MIDIKeyboard;
+	CMIDIKeyboard *m_pMIDIKeyboard[CConfig::MaxUSBMIDIDevices];
 	CPCKeyboard m_PCKeyboard;
 	CSerialMIDIDevice m_SerialMIDI;
 	bool m_bUseSerial;