AUDIO: add support for OPL2LPT

The OPL2LPT is an OPL2 chip plugged on a parallel port. It is
write-only but otherwise acts as a classic AdLib. This commit adds
support for this device.

User is expected to have the right permissions on the parallel
port. By default, the first suitable parallel port is used. It is
possible to override that with the hidden configuration setting
"opl2lpt_parport".

It depends on the presence of the libieee1284 library which abstracts
a bit parallel port handling. An alternative would be to access
directly /dev/parportX on Linux. This would amount of code but it
would be Linux-only.

Tested with Indy 3 and SOMI.

1 files changed, 20 insertions, 1 deletions

diff --git a/audio/fmopl.cpp b/audio/fmopl.cpp
index 3756d98123..3a003c80d9 100644
--- a/audio/fmopl.cpp
+++ b/audio/fmopl.cpp
@@ -43,6 +43,12 @@ namespace ALSA {
 } // End of namespace ALSA
 #endif // USE_ALSA
 
+#ifdef ENABLE_OPL2LPT
+namespace OPL2LPT {
+	OPL *create();
+} // End of namespace OPL2LPT
+#endif // ENABLE_OPL2LPT
+
 // Config implementation
 
 enum OplEmulator {
@@ -50,7 +56,8 @@ enum OplEmulator {
 	kMame = 1,
 	kDOSBox = 2,
 	kALSA = 3,
-	kNuked = 4
+	kNuked = 4,
+	kOPL2LPT = 5
 };
 
 OPL::OPL() {
@@ -71,6 +78,9 @@ const Config::EmulatorDescription Config::_drivers[] = {
 #ifdef USE_ALSA
 	{ "alsa", _s("ALSA Direct FM"), kALSA, kFlagOpl2 | kFlagDualOpl2 | kFlagOpl3 },
 #endif
+#ifdef ENABLE_OPL2LPT
+	{ "opl2lpt", _s("OPL2LPT"), kOPL2LPT, kFlagOpl2 },
+#endif
 	{ 0, 0, 0, 0 }
 };
 
@@ -193,6 +203,15 @@ OPL *Config::create(DriverId driver, OplType type) {
 		return ALSA::create(type);
 #endif
 
+#ifdef ENABLE_OPL2LPT
+	case kOPL2LPT:
+		if (type == kOpl2)
+			return OPL2LPT::create();
+		else
+			warning("OPL2LPT only supports OPL2");
+		return 0;
+#endif
+
 	default:
 		warning("Unsupported OPL emulator %d", driver);
 		// TODO: Maybe we should add some dummy emulator too, which just outputs