ALSA: seq: Allow the tristate build of OSS emulation

Currently OSS sequencer emulation is tied with ALSA sequencer core,
both are built in the same level; i.e. when CONFIG_SND_SEQUENCER=y,
the OSS sequencer emulation is also always built-in, even though the
functionality can be built as an individual module.

This patch changes the rule and allows users to build snd-seq-oss
module while others are built-in.  Essentially, it's just a few simple
changes in Kconfig and Makefile.  Some driver codes like opl3 need to
convert from the simple ifdef to IS_ENABLED().  But that's all.

You might wonder how about the dependency: right, it can be messy, but
it still works.  Since we rewrote the sequencer binding with the
standard bus, the driver can be bound at any time on demand.  So, the
synthesizer driver module can be loaded individually from the OSS
emulation core before/after it.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

9 files changed, 18 insertions, 20 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index 3a9afc520d4e..d64dbee36986 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -110,7 +110,7 @@ config SND_PCM_TIMER
 	  footprint, about 20KB on x86_64 platform.
 
 config SND_SEQUENCER_OSS
-	bool "OSS Sequencer API"
+	tristate "OSS Sequencer API"
 	depends on SND_SEQUENCER
 	depends on SND_OSSEMUL
 	help
diff --git a/sound/core/seq/Makefile b/sound/core/seq/Makefile
index b65fa5a1943b..3283b055e5ff 100644
--- a/sound/core/seq/Makefile
+++ b/sound/core/seq/Makefile
@@ -15,10 +15,9 @@ snd-seq-dummy-objs := seq_dummy.o
 snd-seq-virmidi-objs := seq_virmidi.o
 
 obj-$(CONFIG_SND_SEQUENCER) += snd-seq.o snd-seq-device.o
-ifeq ($(CONFIG_SND_SEQUENCER_OSS),y)
-  obj-$(CONFIG_SND_SEQUENCER) += snd-seq-midi-event.o
-  obj-$(CONFIG_SND_SEQUENCER) += oss/
-endif
+obj-$(CONFIG_SND_SEQUENCER_OSS) += snd-seq-midi-event.o
+obj-$(CONFIG_SND_SEQUENCER_OSS) += oss/
+
 obj-$(CONFIG_SND_SEQ_DUMMY) += snd-seq-dummy.o
 
 # Toplevel Module Dependency
diff --git a/sound/core/seq/oss/Makefile b/sound/core/seq/oss/Makefile
index b38406b8463c..4ea4e3eea6b7 100644
--- a/sound/core/seq/oss/Makefile
+++ b/sound/core/seq/oss/Makefile
@@ -7,4 +7,4 @@ snd-seq-oss-objs  := seq_oss.o seq_oss_init.o seq_oss_timer.o seq_oss_ioctl.o \
 		     seq_oss_event.o seq_oss_rw.o seq_oss_synth.o \
 		     seq_oss_midi.o seq_oss_readq.o seq_oss_writeq.o
 
-obj-$(CONFIG_SND_SEQUENCER) += snd-seq-oss.o
+obj-$(CONFIG_SND_SEQUENCER_OSS) += snd-seq-oss.o
diff --git a/sound/drivers/opl3/opl3_seq.c b/sound/drivers/opl3/opl3_seq.c
index fdae5d7f421f..d3e91be8b23a 100644
--- a/sound/drivers/opl3/opl3_seq.c
+++ b/sound/drivers/opl3/opl3_seq.c
@@ -252,7 +252,7 @@ static int snd_opl3_seq_probe(struct device *_dev)
 	spin_lock_init(&opl3->sys_timer_lock);
 	opl3->sys_timer_status = 0;
 
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	snd_opl3_init_seq_oss(opl3, name);
 #endif
 	return 0;
@@ -267,7 +267,7 @@ static int snd_opl3_seq_remove(struct device *_dev)
 	if (opl3 == NULL)
 		return -EINVAL;
 
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	snd_opl3_free_seq_oss(opl3);
 #endif
 	if (opl3->seq_client >= 0) {
diff --git a/sound/drivers/opl3/opl3_voice.h b/sound/drivers/opl3/opl3_voice.h
index a371c075ac87..eaef435e0528 100644
--- a/sound/drivers/opl3/opl3_voice.h
+++ b/sound/drivers/opl3/opl3_voice.h
@@ -44,9 +44,12 @@ void snd_opl3_load_drums(struct snd_opl3 *opl3);
 void snd_opl3_drum_switch(struct snd_opl3 *opl3, int note, int on_off, int vel, struct snd_midi_channel *chan);
 
 /* Prototypes for opl3_oss.c */
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 void snd_opl3_init_seq_oss(struct snd_opl3 *opl3, char *name);
 void snd_opl3_free_seq_oss(struct snd_opl3 *opl3);
+#else
+#define snd_opl3_init_seq_oss(opl3, name) /* NOP */
+#define snd_opl3_free_seq_oss(opl3) /* NOP */
 #endif
 
 #endif
diff --git a/sound/isa/sb/emu8000_callback.c b/sound/isa/sb/emu8000_callback.c
index 72a9ac5efb40..d28d712f99f4 100644
--- a/sound/isa/sb/emu8000_callback.c
+++ b/sound/isa/sb/emu8000_callback.c
@@ -36,7 +36,7 @@ static void reset_voice(struct snd_emux *emu, int ch);
 static void terminate_voice(struct snd_emux_voice *vp);
 static void sysex(struct snd_emux *emu, char *buf, int len, int parsed,
 		  struct snd_midi_channel_set *chset);
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 static int oss_ioctl(struct snd_emux *emu, int cmd, int p1, int p2);
 #endif
 static int load_fx(struct snd_emux *emu, int type, int mode,
@@ -76,7 +76,7 @@ static struct snd_emux_operators emu8000_ops = {
 	.sample_reset = snd_emu8000_sample_reset,
 	.load_fx =	load_fx,
 	.sysex =	sysex,
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	.oss_ioctl =	oss_ioctl,
 #endif
 };
@@ -477,7 +477,7 @@ sysex(struct snd_emux *emu, char *buf, int len, int parsed, struct snd_midi_chan
 }
 
 
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 /*
  * OSS ioctl callback
  */
diff --git a/sound/synth/emux/emux.c b/sound/synth/emux/emux.c
index 9312cd8a6fdd..b9981e8c0027 100644
--- a/sound/synth/emux/emux.c
+++ b/sound/synth/emux/emux.c
@@ -47,7 +47,7 @@ int snd_emux_new(struct snd_emux **remu)
 	mutex_init(&emu->register_mutex);
 
 	emu->client = -1;
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	emu->oss_synth = NULL;
 #endif
 	emu->max_voices = 0;
@@ -123,7 +123,7 @@ int snd_emux_register(struct snd_emux *emu, struct snd_card *card, int index, ch
 	snd_emux_init_voices(emu);
 
 	snd_emux_init_seq(emu, card, index);
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	snd_emux_init_seq_oss(emu);
 #endif
 	snd_emux_init_virmidi(emu, card);
@@ -150,7 +150,7 @@ int snd_emux_free(struct snd_emux *emu)
 
 	snd_emux_proc_free(emu);
 	snd_emux_delete_virmidi(emu);
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 	snd_emux_detach_seq_oss(emu);
 #endif
 	snd_emux_detach_seq(emu);
diff --git a/sound/synth/emux/emux_effect.c b/sound/synth/emux/emux_effect.c
index a447218b6160..9ac0bf531b4b 100644
--- a/sound/synth/emux/emux_effect.c
+++ b/sound/synth/emux/emux_effect.c
@@ -150,7 +150,7 @@ effect_get_offset(struct snd_midi_channel *chan, int lo, int hi, int mode)
 	return addr;
 }
 
-#ifdef CONFIG_SND_SEQUENCER_OSS
+#if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
 /* change effects - for OSS sequencer compatibility */
 void
 snd_emux_send_effect_oss(struct snd_emux_port *port,
diff --git a/sound/synth/emux/emux_oss.c b/sound/synth/emux/emux_oss.c
index 850fab4a8f3b..de19e108974a 100644
--- a/sound/synth/emux/emux_oss.c
+++ b/sound/synth/emux/emux_oss.c
@@ -23,8 +23,6 @@
  */
 
 
-#ifdef CONFIG_SND_SEQUENCER_OSS
-
 #include <linux/export.h>
 #include <linux/uaccess.h>
 #include <sound/core.h>
@@ -505,5 +503,3 @@ fake_event(struct snd_emux *emu, struct snd_emux_port *port, int ch, int param,
 	ev.data.control.value = val;
 	snd_emux_event_input(&ev, 0, port, atomic, hop);
 }
-
-#endif /* CONFIG_SND_SEQUENCER_OSS */