xref: /openbmc/linux/sound/drivers/opl3/opl3_synth.c (revision 7f6964c5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (c) by Uros Bizjak <uros@kss-loka.si>
4  *
5  *  Routines for OPL2/OPL3/OPL4 control
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/export.h>
10 #include <linux/nospec.h>
11 #include <sound/opl3.h>
12 #include <sound/asound_fm.h>
13 #include "opl3_voice.h"
14 
15 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
16 #define OPL3_SUPPORT_SYNTH
17 #endif
18 
19 /*
20  *    There is 18 possible 2 OP voices
21  *      (9 in the left and 9 in the right).
22  *      The first OP is the modulator and 2nd is the carrier.
23  *
24  *      The first three voices in the both sides may be connected
25  *      with another voice to a 4 OP voice. For example voice 0
26  *      can be connected with voice 3. The operators of voice 3 are
27  *      used as operators 3 and 4 of the new 4 OP voice.
28  *      In this case the 2 OP voice number 0 is the 'first half' and
29  *      voice 3 is the second.
30  */
31 
32 
33 /*
34  *    Register offset table for OPL2/3 voices,
35  *    OPL2 / one OPL3 register array side only
36  */
37 
38 char snd_opl3_regmap[MAX_OPL2_VOICES][4] =
39 {
40 /*	  OP1   OP2   OP3   OP4		*/
41 /*	 ------------------------	*/
42 	{ 0x00, 0x03, 0x08, 0x0b },
43 	{ 0x01, 0x04, 0x09, 0x0c },
44 	{ 0x02, 0x05, 0x0a, 0x0d },
45 
46 	{ 0x08, 0x0b, 0x00, 0x00 },
47 	{ 0x09, 0x0c, 0x00, 0x00 },
48 	{ 0x0a, 0x0d, 0x00, 0x00 },
49 
50 	{ 0x10, 0x13, 0x00, 0x00 },	/* used by percussive voices */
51 	{ 0x11, 0x14, 0x00, 0x00 },	/* if the percussive mode */
52 	{ 0x12, 0x15, 0x00, 0x00 }	/* is selected (only left reg block) */
53 };
54 
55 EXPORT_SYMBOL(snd_opl3_regmap);
56 
57 /*
58  * prototypes
59  */
60 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note);
61 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice);
62 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params);
63 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode);
64 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection);
65 
66 /* ------------------------------ */
67 
68 /*
69  * open the device exclusively
70  */
71 int snd_opl3_open(struct snd_hwdep * hw, struct file *file)
72 {
73 	return 0;
74 }
75 
76 /*
77  * ioctl for hwdep device:
78  */
79 int snd_opl3_ioctl(struct snd_hwdep * hw, struct file *file,
80 		   unsigned int cmd, unsigned long arg)
81 {
82 	struct snd_opl3 *opl3 = hw->private_data;
83 	void __user *argp = (void __user *)arg;
84 
85 	if (snd_BUG_ON(!opl3))
86 		return -EINVAL;
87 
88 	switch (cmd) {
89 		/* get information */
90 	case SNDRV_DM_FM_IOCTL_INFO:
91 		{
92 			struct snd_dm_fm_info info;
93 
94 			info.fm_mode = opl3->fm_mode;
95 			info.rhythm = opl3->rhythm;
96 			if (copy_to_user(argp, &info, sizeof(struct snd_dm_fm_info)))
97 				return -EFAULT;
98 			return 0;
99 		}
100 
101 	case SNDRV_DM_FM_IOCTL_RESET:
102 #ifdef CONFIG_SND_OSSEMUL
103 	case SNDRV_DM_FM_OSS_IOCTL_RESET:
104 #endif
105 		snd_opl3_reset(opl3);
106 		return 0;
107 
108 	case SNDRV_DM_FM_IOCTL_PLAY_NOTE:
109 #ifdef CONFIG_SND_OSSEMUL
110 	case SNDRV_DM_FM_OSS_IOCTL_PLAY_NOTE:
111 #endif
112 		{
113 			struct snd_dm_fm_note note;
114 			if (copy_from_user(&note, argp, sizeof(struct snd_dm_fm_note)))
115 				return -EFAULT;
116 			return snd_opl3_play_note(opl3, &note);
117 		}
118 
119 	case SNDRV_DM_FM_IOCTL_SET_VOICE:
120 #ifdef CONFIG_SND_OSSEMUL
121 	case SNDRV_DM_FM_OSS_IOCTL_SET_VOICE:
122 #endif
123 		{
124 			struct snd_dm_fm_voice voice;
125 			if (copy_from_user(&voice, argp, sizeof(struct snd_dm_fm_voice)))
126 				return -EFAULT;
127 			return snd_opl3_set_voice(opl3, &voice);
128 		}
129 
130 	case SNDRV_DM_FM_IOCTL_SET_PARAMS:
131 #ifdef CONFIG_SND_OSSEMUL
132 	case SNDRV_DM_FM_OSS_IOCTL_SET_PARAMS:
133 #endif
134 		{
135 			struct snd_dm_fm_params params;
136 			if (copy_from_user(&params, argp, sizeof(struct snd_dm_fm_params)))
137 				return -EFAULT;
138 			return snd_opl3_set_params(opl3, &params);
139 		}
140 
141 	case SNDRV_DM_FM_IOCTL_SET_MODE:
142 #ifdef CONFIG_SND_OSSEMUL
143 	case SNDRV_DM_FM_OSS_IOCTL_SET_MODE:
144 #endif
145 		return snd_opl3_set_mode(opl3, (int) arg);
146 
147 	case SNDRV_DM_FM_IOCTL_SET_CONNECTION:
148 #ifdef CONFIG_SND_OSSEMUL
149 	case SNDRV_DM_FM_OSS_IOCTL_SET_OPL:
150 #endif
151 		return snd_opl3_set_connection(opl3, (int) arg);
152 
153 #ifdef OPL3_SUPPORT_SYNTH
154 	case SNDRV_DM_FM_IOCTL_CLEAR_PATCHES:
155 		snd_opl3_clear_patches(opl3);
156 		return 0;
157 #endif
158 
159 #ifdef CONFIG_SND_DEBUG
160 	default:
161 		snd_printk(KERN_WARNING "unknown IOCTL: 0x%x\n", cmd);
162 #endif
163 	}
164 	return -ENOTTY;
165 }
166 
167 /*
168  * close the device
169  */
170 int snd_opl3_release(struct snd_hwdep * hw, struct file *file)
171 {
172 	struct snd_opl3 *opl3 = hw->private_data;
173 
174 	snd_opl3_reset(opl3);
175 	return 0;
176 }
177 
178 #ifdef OPL3_SUPPORT_SYNTH
179 /*
180  * write the device - load patches
181  */
182 long snd_opl3_write(struct snd_hwdep *hw, const char __user *buf, long count,
183 		    loff_t *offset)
184 {
185 	struct snd_opl3 *opl3 = hw->private_data;
186 	long result = 0;
187 	int err = 0;
188 	struct sbi_patch inst;
189 
190 	while (count >= sizeof(inst)) {
191 		unsigned char type;
192 		if (copy_from_user(&inst, buf, sizeof(inst)))
193 			return -EFAULT;
194 		if (!memcmp(inst.key, FM_KEY_SBI, 4) ||
195 		    !memcmp(inst.key, FM_KEY_2OP, 4))
196 			type = FM_PATCH_OPL2;
197 		else if (!memcmp(inst.key, FM_KEY_4OP, 4))
198 			type = FM_PATCH_OPL3;
199 		else /* invalid type */
200 			break;
201 		err = snd_opl3_load_patch(opl3, inst.prog, inst.bank, type,
202 					  inst.name, inst.extension,
203 					  inst.data);
204 		if (err < 0)
205 			break;
206 		result += sizeof(inst);
207 		count -= sizeof(inst);
208 	}
209 	return result > 0 ? result : err;
210 }
211 
212 
213 /*
214  * Patch management
215  */
216 
217 /* offsets for SBI params */
218 #define AM_VIB		0
219 #define KSL_LEVEL	2
220 #define ATTACK_DECAY	4
221 #define SUSTAIN_RELEASE	6
222 #define WAVE_SELECT	8
223 
224 /* offset for SBI instrument */
225 #define CONNECTION	10
226 #define OFFSET_4OP	11
227 
228 /*
229  * load a patch, obviously.
230  *
231  * loaded on the given program and bank numbers with the given type
232  * (FM_PATCH_OPLx).
233  * data is the pointer of SBI record _without_ header (key and name).
234  * name is the name string of the patch.
235  * ext is the extension data of 7 bytes long (stored in name of SBI
236  * data up to offset 25), or NULL to skip.
237  * return 0 if successful or a negative error code.
238  */
239 int snd_opl3_load_patch(struct snd_opl3 *opl3,
240 			int prog, int bank, int type,
241 			const char *name,
242 			const unsigned char *ext,
243 			const unsigned char *data)
244 {
245 	struct fm_patch *patch;
246 	int i;
247 
248 	patch = snd_opl3_find_patch(opl3, prog, bank, 1);
249 	if (!patch)
250 		return -ENOMEM;
251 
252 	patch->type = type;
253 
254 	for (i = 0; i < 2; i++) {
255 		patch->inst.op[i].am_vib = data[AM_VIB + i];
256 		patch->inst.op[i].ksl_level = data[KSL_LEVEL + i];
257 		patch->inst.op[i].attack_decay = data[ATTACK_DECAY + i];
258 		patch->inst.op[i].sustain_release = data[SUSTAIN_RELEASE + i];
259 		patch->inst.op[i].wave_select = data[WAVE_SELECT + i];
260 	}
261 	patch->inst.feedback_connection[0] = data[CONNECTION];
262 
263 	if (type == FM_PATCH_OPL3) {
264 		for (i = 0; i < 2; i++) {
265 			patch->inst.op[i+2].am_vib =
266 				data[OFFSET_4OP + AM_VIB + i];
267 			patch->inst.op[i+2].ksl_level =
268 				data[OFFSET_4OP + KSL_LEVEL + i];
269 			patch->inst.op[i+2].attack_decay =
270 				data[OFFSET_4OP + ATTACK_DECAY + i];
271 			patch->inst.op[i+2].sustain_release =
272 				data[OFFSET_4OP + SUSTAIN_RELEASE + i];
273 			patch->inst.op[i+2].wave_select =
274 				data[OFFSET_4OP + WAVE_SELECT + i];
275 		}
276 		patch->inst.feedback_connection[1] =
277 			data[OFFSET_4OP + CONNECTION];
278 	}
279 
280 	if (ext) {
281 		patch->inst.echo_delay = ext[0];
282 		patch->inst.echo_atten = ext[1];
283 		patch->inst.chorus_spread = ext[2];
284 		patch->inst.trnsps = ext[3];
285 		patch->inst.fix_dur = ext[4];
286 		patch->inst.modes = ext[5];
287 		patch->inst.fix_key = ext[6];
288 	}
289 
290 	if (name)
291 		strlcpy(patch->name, name, sizeof(patch->name));
292 
293 	return 0;
294 }
295 EXPORT_SYMBOL(snd_opl3_load_patch);
296 
297 /*
298  * find a patch with the given program and bank numbers, returns its pointer
299  * if no matching patch is found and create_patch is set, it creates a
300  * new patch object.
301  */
302 struct fm_patch *snd_opl3_find_patch(struct snd_opl3 *opl3, int prog, int bank,
303 				     int create_patch)
304 {
305 	/* pretty dumb hash key */
306 	unsigned int key = (prog + bank) % OPL3_PATCH_HASH_SIZE;
307 	struct fm_patch *patch;
308 
309 	for (patch = opl3->patch_table[key]; patch; patch = patch->next) {
310 		if (patch->prog == prog && patch->bank == bank)
311 			return patch;
312 	}
313 	if (!create_patch)
314 		return NULL;
315 
316 	patch = kzalloc(sizeof(*patch), GFP_KERNEL);
317 	if (!patch)
318 		return NULL;
319 	patch->prog = prog;
320 	patch->bank = bank;
321 	patch->next = opl3->patch_table[key];
322 	opl3->patch_table[key] = patch;
323 	return patch;
324 }
325 EXPORT_SYMBOL(snd_opl3_find_patch);
326 
327 /*
328  * Clear all patches of the given OPL3 instance
329  */
330 void snd_opl3_clear_patches(struct snd_opl3 *opl3)
331 {
332 	int i;
333 	for (i = 0; i <  OPL3_PATCH_HASH_SIZE; i++) {
334 		struct fm_patch *patch, *next;
335 		for (patch = opl3->patch_table[i]; patch; patch = next) {
336 			next = patch->next;
337 			kfree(patch);
338 		}
339 	}
340 	memset(opl3->patch_table, 0, sizeof(opl3->patch_table));
341 }
342 #endif /* OPL3_SUPPORT_SYNTH */
343 
344 /* ------------------------------ */
345 
346 void snd_opl3_reset(struct snd_opl3 * opl3)
347 {
348 	unsigned short opl3_reg;
349 
350 	unsigned short reg_side;
351 	unsigned char voice_offset;
352 
353 	int max_voices, i;
354 
355 	max_voices = (opl3->hardware < OPL3_HW_OPL3) ?
356 		MAX_OPL2_VOICES : MAX_OPL3_VOICES;
357 
358 	for (i = 0; i < max_voices; i++) {
359 		/* Get register array side and offset of voice */
360 		if (i < MAX_OPL2_VOICES) {
361 			/* Left register block for voices 0 .. 8 */
362 			reg_side = OPL3_LEFT;
363 			voice_offset = i;
364 		} else {
365 			/* Right register block for voices 9 .. 17 */
366 			reg_side = OPL3_RIGHT;
367 			voice_offset = i - MAX_OPL2_VOICES;
368 		}
369 		opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][0]);
370 		opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 1 volume */
371 		opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][1]);
372 		opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 2 volume */
373 
374 		opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
375 		opl3->command(opl3, opl3_reg, 0x00);	/* Note off */
376 	}
377 
378 	opl3->max_voices = MAX_OPL2_VOICES;
379 	opl3->fm_mode = SNDRV_DM_FM_MODE_OPL2;
380 
381 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_TEST, OPL3_ENABLE_WAVE_SELECT);
382 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, 0x00);	/* Melodic mode */
383 	opl3->rhythm = 0;
384 }
385 
386 EXPORT_SYMBOL(snd_opl3_reset);
387 
388 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note)
389 {
390 	unsigned short reg_side;
391 	unsigned char voice_offset;
392 
393 	unsigned short opl3_reg;
394 	unsigned char reg_val;
395 
396 	/* Voices 0 -  8 in OPL2 mode */
397 	/* Voices 0 - 17 in OPL3 mode */
398 	if (note->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
399 			    MAX_OPL3_VOICES : MAX_OPL2_VOICES))
400 		return -EINVAL;
401 
402 	/* Get register array side and offset of voice */
403 	if (note->voice < MAX_OPL2_VOICES) {
404 		/* Left register block for voices 0 .. 8 */
405 		reg_side = OPL3_LEFT;
406 		voice_offset = note->voice;
407 	} else {
408 		/* Right register block for voices 9 .. 17 */
409 		reg_side = OPL3_RIGHT;
410 		voice_offset = note->voice - MAX_OPL2_VOICES;
411 	}
412 
413 	/* Set lower 8 bits of note frequency */
414 	reg_val = (unsigned char) note->fnum;
415 	opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
416 	opl3->command(opl3, opl3_reg, reg_val);
417 
418 	reg_val = 0x00;
419 	/* Set output sound flag */
420 	if (note->key_on)
421 		reg_val |= OPL3_KEYON_BIT;
422 	/* Set octave */
423 	reg_val |= (note->octave << 2) & OPL3_BLOCKNUM_MASK;
424 	/* Set higher 2 bits of note frequency */
425 	reg_val |= (unsigned char) (note->fnum >> 8) & OPL3_FNUM_HIGH_MASK;
426 
427 	/* Set OPL3 KEYON_BLOCK register of requested voice */
428 	opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
429 	opl3->command(opl3, opl3_reg, reg_val);
430 
431 	return 0;
432 }
433 
434 
435 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice)
436 {
437 	unsigned short reg_side;
438 	unsigned char op_offset;
439 	unsigned char voice_offset, voice_op;
440 
441 	unsigned short opl3_reg;
442 	unsigned char reg_val;
443 
444 	/* Only operators 1 and 2 */
445 	if (voice->op > 1)
446 		return -EINVAL;
447 	/* Voices 0 -  8 in OPL2 mode */
448 	/* Voices 0 - 17 in OPL3 mode */
449 	if (voice->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
450 			     MAX_OPL3_VOICES : MAX_OPL2_VOICES))
451 		return -EINVAL;
452 
453 	/* Get register array side and offset of voice */
454 	if (voice->voice < MAX_OPL2_VOICES) {
455 		/* Left register block for voices 0 .. 8 */
456 		reg_side = OPL3_LEFT;
457 		voice_offset = voice->voice;
458 	} else {
459 		/* Right register block for voices 9 .. 17 */
460 		reg_side = OPL3_RIGHT;
461 		voice_offset = voice->voice - MAX_OPL2_VOICES;
462 	}
463 	/* Get register offset of operator */
464 	voice_offset = array_index_nospec(voice_offset, MAX_OPL2_VOICES);
465 	voice_op = array_index_nospec(voice->op, 4);
466 	op_offset = snd_opl3_regmap[voice_offset][voice_op];
467 
468 	reg_val = 0x00;
469 	/* Set amplitude modulation (tremolo) effect */
470 	if (voice->am)
471 		reg_val |= OPL3_TREMOLO_ON;
472 	/* Set vibrato effect */
473 	if (voice->vibrato)
474 		reg_val |= OPL3_VIBRATO_ON;
475 	/* Set sustaining sound phase */
476 	if (voice->do_sustain)
477 		reg_val |= OPL3_SUSTAIN_ON;
478 	/* Set keyboard scaling bit */
479 	if (voice->kbd_scale)
480 		reg_val |= OPL3_KSR;
481 	/* Set harmonic or frequency multiplier */
482 	reg_val |= voice->harmonic & OPL3_MULTIPLE_MASK;
483 
484 	/* Set OPL3 AM_VIB register of requested voice/operator */
485 	opl3_reg = reg_side | (OPL3_REG_AM_VIB + op_offset);
486 	opl3->command(opl3, opl3_reg, reg_val);
487 
488 	/* Set decreasing volume of higher notes */
489 	reg_val = (voice->scale_level << 6) & OPL3_KSL_MASK;
490 	/* Set output volume */
491 	reg_val |= ~voice->volume & OPL3_TOTAL_LEVEL_MASK;
492 
493 	/* Set OPL3 KSL_LEVEL register of requested voice/operator */
494 	opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + op_offset);
495 	opl3->command(opl3, opl3_reg, reg_val);
496 
497 	/* Set attack phase level */
498 	reg_val = (voice->attack << 4) & OPL3_ATTACK_MASK;
499 	/* Set decay phase level */
500 	reg_val |= voice->decay & OPL3_DECAY_MASK;
501 
502 	/* Set OPL3 ATTACK_DECAY register of requested voice/operator */
503 	opl3_reg = reg_side | (OPL3_REG_ATTACK_DECAY + op_offset);
504 	opl3->command(opl3, opl3_reg, reg_val);
505 
506 	/* Set sustain phase level */
507 	reg_val = (voice->sustain << 4) & OPL3_SUSTAIN_MASK;
508 	/* Set release phase level */
509 	reg_val |= voice->release & OPL3_RELEASE_MASK;
510 
511 	/* Set OPL3 SUSTAIN_RELEASE register of requested voice/operator */
512 	opl3_reg = reg_side | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
513 	opl3->command(opl3, opl3_reg, reg_val);
514 
515 	/* Set inter-operator feedback */
516 	reg_val = (voice->feedback << 1) & OPL3_FEEDBACK_MASK;
517 	/* Set inter-operator connection */
518 	if (voice->connection)
519 		reg_val |= OPL3_CONNECTION_BIT;
520 	/* OPL-3 only */
521 	if (opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) {
522 		if (voice->left)
523 			reg_val |= OPL3_VOICE_TO_LEFT;
524 		if (voice->right)
525 			reg_val |= OPL3_VOICE_TO_RIGHT;
526 	}
527 	/* Feedback/connection bits are applicable to voice */
528 	opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
529 	opl3->command(opl3, opl3_reg, reg_val);
530 
531 	/* Select waveform */
532 	reg_val = voice->waveform & OPL3_WAVE_SELECT_MASK;
533 	opl3_reg = reg_side | (OPL3_REG_WAVE_SELECT + op_offset);
534 	opl3->command(opl3, opl3_reg, reg_val);
535 
536 	return 0;
537 }
538 
539 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params)
540 {
541 	unsigned char reg_val;
542 
543 	reg_val = 0x00;
544 	/* Set keyboard split method */
545 	if (params->kbd_split)
546 		reg_val |= OPL3_KEYBOARD_SPLIT;
547 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_KBD_SPLIT, reg_val);
548 
549 	reg_val = 0x00;
550 	/* Set amplitude modulation (tremolo) depth */
551 	if (params->am_depth)
552 		reg_val |= OPL3_TREMOLO_DEPTH;
553 	/* Set vibrato depth */
554 	if (params->vib_depth)
555 		reg_val |= OPL3_VIBRATO_DEPTH;
556 	/* Set percussion mode */
557 	if (params->rhythm) {
558 		reg_val |= OPL3_PERCUSSION_ENABLE;
559 		opl3->rhythm = 1;
560 	} else {
561 		opl3->rhythm = 0;
562 	}
563 	/* Play percussion instruments */
564 	if (params->bass)
565 		reg_val |= OPL3_BASSDRUM_ON;
566 	if (params->snare)
567 		reg_val |= OPL3_SNAREDRUM_ON;
568 	if (params->tomtom)
569 		reg_val |= OPL3_TOMTOM_ON;
570 	if (params->cymbal)
571 		reg_val |= OPL3_CYMBAL_ON;
572 	if (params->hihat)
573 		reg_val |= OPL3_HIHAT_ON;
574 
575 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, reg_val);
576 	return 0;
577 }
578 
579 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode)
580 {
581 	if ((mode == SNDRV_DM_FM_MODE_OPL3) && (opl3->hardware < OPL3_HW_OPL3))
582 		return -EINVAL;
583 
584 	opl3->fm_mode = mode;
585 	if (opl3->hardware >= OPL3_HW_OPL3)
586 		opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, 0x00);	/* Clear 4-op connections */
587 
588 	return 0;
589 }
590 
591 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection)
592 {
593 	unsigned char reg_val;
594 
595 	/* OPL-3 only */
596 	if (opl3->fm_mode != SNDRV_DM_FM_MODE_OPL3)
597 		return -EINVAL;
598 
599 	reg_val = connection & (OPL3_RIGHT_4OP_0 | OPL3_RIGHT_4OP_1 | OPL3_RIGHT_4OP_2 |
600 				OPL3_LEFT_4OP_0 | OPL3_LEFT_4OP_1 | OPL3_LEFT_4OP_2);
601 	/* Set 4-op connections */
602 	opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, reg_val);
603 
604 	return 0;
605 }
606 
607