xref: /openbmc/linux/sound/drivers/opl3/opl3_synth.c (revision 293d5b43)
1 /*
2  *  Copyright (c) by Uros Bizjak <uros@kss-loka.si>
3  *
4  *  Routines for OPL2/OPL3/OPL4 control
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/slab.h>
23 #include <linux/export.h>
24 #include <sound/opl3.h>
25 #include <sound/asound_fm.h>
26 
27 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
28 #define OPL3_SUPPORT_SYNTH
29 #endif
30 
31 /*
32  *    There is 18 possible 2 OP voices
33  *      (9 in the left and 9 in the right).
34  *      The first OP is the modulator and 2nd is the carrier.
35  *
36  *      The first three voices in the both sides may be connected
37  *      with another voice to a 4 OP voice. For example voice 0
38  *      can be connected with voice 3. The operators of voice 3 are
39  *      used as operators 3 and 4 of the new 4 OP voice.
40  *      In this case the 2 OP voice number 0 is the 'first half' and
41  *      voice 3 is the second.
42  */
43 
44 
45 /*
46  *    Register offset table for OPL2/3 voices,
47  *    OPL2 / one OPL3 register array side only
48  */
49 
50 char snd_opl3_regmap[MAX_OPL2_VOICES][4] =
51 {
52 /*	  OP1   OP2   OP3   OP4		*/
53 /*	 ------------------------	*/
54 	{ 0x00, 0x03, 0x08, 0x0b },
55 	{ 0x01, 0x04, 0x09, 0x0c },
56 	{ 0x02, 0x05, 0x0a, 0x0d },
57 
58 	{ 0x08, 0x0b, 0x00, 0x00 },
59 	{ 0x09, 0x0c, 0x00, 0x00 },
60 	{ 0x0a, 0x0d, 0x00, 0x00 },
61 
62 	{ 0x10, 0x13, 0x00, 0x00 },	/* used by percussive voices */
63 	{ 0x11, 0x14, 0x00, 0x00 },	/* if the percussive mode */
64 	{ 0x12, 0x15, 0x00, 0x00 }	/* is selected (only left reg block) */
65 };
66 
67 EXPORT_SYMBOL(snd_opl3_regmap);
68 
69 /*
70  * prototypes
71  */
72 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note);
73 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice);
74 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params);
75 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode);
76 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection);
77 
78 /* ------------------------------ */
79 
80 /*
81  * open the device exclusively
82  */
83 int snd_opl3_open(struct snd_hwdep * hw, struct file *file)
84 {
85 	return 0;
86 }
87 
88 /*
89  * ioctl for hwdep device:
90  */
91 int snd_opl3_ioctl(struct snd_hwdep * hw, struct file *file,
92 		   unsigned int cmd, unsigned long arg)
93 {
94 	struct snd_opl3 *opl3 = hw->private_data;
95 	void __user *argp = (void __user *)arg;
96 
97 	if (snd_BUG_ON(!opl3))
98 		return -EINVAL;
99 
100 	switch (cmd) {
101 		/* get information */
102 	case SNDRV_DM_FM_IOCTL_INFO:
103 		{
104 			struct snd_dm_fm_info info;
105 
106 			info.fm_mode = opl3->fm_mode;
107 			info.rhythm = opl3->rhythm;
108 			if (copy_to_user(argp, &info, sizeof(struct snd_dm_fm_info)))
109 				return -EFAULT;
110 			return 0;
111 		}
112 
113 	case SNDRV_DM_FM_IOCTL_RESET:
114 #ifdef CONFIG_SND_OSSEMUL
115 	case SNDRV_DM_FM_OSS_IOCTL_RESET:
116 #endif
117 		snd_opl3_reset(opl3);
118 		return 0;
119 
120 	case SNDRV_DM_FM_IOCTL_PLAY_NOTE:
121 #ifdef CONFIG_SND_OSSEMUL
122 	case SNDRV_DM_FM_OSS_IOCTL_PLAY_NOTE:
123 #endif
124 		{
125 			struct snd_dm_fm_note note;
126 			if (copy_from_user(&note, argp, sizeof(struct snd_dm_fm_note)))
127 				return -EFAULT;
128 			return snd_opl3_play_note(opl3, &note);
129 		}
130 
131 	case SNDRV_DM_FM_IOCTL_SET_VOICE:
132 #ifdef CONFIG_SND_OSSEMUL
133 	case SNDRV_DM_FM_OSS_IOCTL_SET_VOICE:
134 #endif
135 		{
136 			struct snd_dm_fm_voice voice;
137 			if (copy_from_user(&voice, argp, sizeof(struct snd_dm_fm_voice)))
138 				return -EFAULT;
139 			return snd_opl3_set_voice(opl3, &voice);
140 		}
141 
142 	case SNDRV_DM_FM_IOCTL_SET_PARAMS:
143 #ifdef CONFIG_SND_OSSEMUL
144 	case SNDRV_DM_FM_OSS_IOCTL_SET_PARAMS:
145 #endif
146 		{
147 			struct snd_dm_fm_params params;
148 			if (copy_from_user(&params, argp, sizeof(struct snd_dm_fm_params)))
149 				return -EFAULT;
150 			return snd_opl3_set_params(opl3, &params);
151 		}
152 
153 	case SNDRV_DM_FM_IOCTL_SET_MODE:
154 #ifdef CONFIG_SND_OSSEMUL
155 	case SNDRV_DM_FM_OSS_IOCTL_SET_MODE:
156 #endif
157 		return snd_opl3_set_mode(opl3, (int) arg);
158 
159 	case SNDRV_DM_FM_IOCTL_SET_CONNECTION:
160 #ifdef CONFIG_SND_OSSEMUL
161 	case SNDRV_DM_FM_OSS_IOCTL_SET_OPL:
162 #endif
163 		return snd_opl3_set_connection(opl3, (int) arg);
164 
165 #ifdef OPL3_SUPPORT_SYNTH
166 	case SNDRV_DM_FM_IOCTL_CLEAR_PATCHES:
167 		snd_opl3_clear_patches(opl3);
168 		return 0;
169 #endif
170 
171 #ifdef CONFIG_SND_DEBUG
172 	default:
173 		snd_printk(KERN_WARNING "unknown IOCTL: 0x%x\n", cmd);
174 #endif
175 	}
176 	return -ENOTTY;
177 }
178 
179 /*
180  * close the device
181  */
182 int snd_opl3_release(struct snd_hwdep * hw, struct file *file)
183 {
184 	struct snd_opl3 *opl3 = hw->private_data;
185 
186 	snd_opl3_reset(opl3);
187 	return 0;
188 }
189 
190 #ifdef OPL3_SUPPORT_SYNTH
191 /*
192  * write the device - load patches
193  */
194 long snd_opl3_write(struct snd_hwdep *hw, const char __user *buf, long count,
195 		    loff_t *offset)
196 {
197 	struct snd_opl3 *opl3 = hw->private_data;
198 	long result = 0;
199 	int err = 0;
200 	struct sbi_patch inst;
201 
202 	while (count >= sizeof(inst)) {
203 		unsigned char type;
204 		if (copy_from_user(&inst, buf, sizeof(inst)))
205 			return -EFAULT;
206 		if (!memcmp(inst.key, FM_KEY_SBI, 4) ||
207 		    !memcmp(inst.key, FM_KEY_2OP, 4))
208 			type = FM_PATCH_OPL2;
209 		else if (!memcmp(inst.key, FM_KEY_4OP, 4))
210 			type = FM_PATCH_OPL3;
211 		else /* invalid type */
212 			break;
213 		err = snd_opl3_load_patch(opl3, inst.prog, inst.bank, type,
214 					  inst.name, inst.extension,
215 					  inst.data);
216 		if (err < 0)
217 			break;
218 		result += sizeof(inst);
219 		count -= sizeof(inst);
220 	}
221 	return result > 0 ? result : err;
222 }
223 
224 
225 /*
226  * Patch management
227  */
228 
229 /* offsets for SBI params */
230 #define AM_VIB		0
231 #define KSL_LEVEL	2
232 #define ATTACK_DECAY	4
233 #define SUSTAIN_RELEASE	6
234 #define WAVE_SELECT	8
235 
236 /* offset for SBI instrument */
237 #define CONNECTION	10
238 #define OFFSET_4OP	11
239 
240 /*
241  * load a patch, obviously.
242  *
243  * loaded on the given program and bank numbers with the given type
244  * (FM_PATCH_OPLx).
245  * data is the pointer of SBI record _without_ header (key and name).
246  * name is the name string of the patch.
247  * ext is the extension data of 7 bytes long (stored in name of SBI
248  * data up to offset 25), or NULL to skip.
249  * return 0 if successful or a negative error code.
250  */
251 int snd_opl3_load_patch(struct snd_opl3 *opl3,
252 			int prog, int bank, int type,
253 			const char *name,
254 			const unsigned char *ext,
255 			const unsigned char *data)
256 {
257 	struct fm_patch *patch;
258 	int i;
259 
260 	patch = snd_opl3_find_patch(opl3, prog, bank, 1);
261 	if (!patch)
262 		return -ENOMEM;
263 
264 	patch->type = type;
265 
266 	for (i = 0; i < 2; i++) {
267 		patch->inst.op[i].am_vib = data[AM_VIB + i];
268 		patch->inst.op[i].ksl_level = data[KSL_LEVEL + i];
269 		patch->inst.op[i].attack_decay = data[ATTACK_DECAY + i];
270 		patch->inst.op[i].sustain_release = data[SUSTAIN_RELEASE + i];
271 		patch->inst.op[i].wave_select = data[WAVE_SELECT + i];
272 	}
273 	patch->inst.feedback_connection[0] = data[CONNECTION];
274 
275 	if (type == FM_PATCH_OPL3) {
276 		for (i = 0; i < 2; i++) {
277 			patch->inst.op[i+2].am_vib =
278 				data[OFFSET_4OP + AM_VIB + i];
279 			patch->inst.op[i+2].ksl_level =
280 				data[OFFSET_4OP + KSL_LEVEL + i];
281 			patch->inst.op[i+2].attack_decay =
282 				data[OFFSET_4OP + ATTACK_DECAY + i];
283 			patch->inst.op[i+2].sustain_release =
284 				data[OFFSET_4OP + SUSTAIN_RELEASE + i];
285 			patch->inst.op[i+2].wave_select =
286 				data[OFFSET_4OP + WAVE_SELECT + i];
287 		}
288 		patch->inst.feedback_connection[1] =
289 			data[OFFSET_4OP + CONNECTION];
290 	}
291 
292 	if (ext) {
293 		patch->inst.echo_delay = ext[0];
294 		patch->inst.echo_atten = ext[1];
295 		patch->inst.chorus_spread = ext[2];
296 		patch->inst.trnsps = ext[3];
297 		patch->inst.fix_dur = ext[4];
298 		patch->inst.modes = ext[5];
299 		patch->inst.fix_key = ext[6];
300 	}
301 
302 	if (name)
303 		strlcpy(patch->name, name, sizeof(patch->name));
304 
305 	return 0;
306 }
307 EXPORT_SYMBOL(snd_opl3_load_patch);
308 
309 /*
310  * find a patch with the given program and bank numbers, returns its pointer
311  * if no matching patch is found and create_patch is set, it creates a
312  * new patch object.
313  */
314 struct fm_patch *snd_opl3_find_patch(struct snd_opl3 *opl3, int prog, int bank,
315 				     int create_patch)
316 {
317 	/* pretty dumb hash key */
318 	unsigned int key = (prog + bank) % OPL3_PATCH_HASH_SIZE;
319 	struct fm_patch *patch;
320 
321 	for (patch = opl3->patch_table[key]; patch; patch = patch->next) {
322 		if (patch->prog == prog && patch->bank == bank)
323 			return patch;
324 	}
325 	if (!create_patch)
326 		return NULL;
327 
328 	patch = kzalloc(sizeof(*patch), GFP_KERNEL);
329 	if (!patch)
330 		return NULL;
331 	patch->prog = prog;
332 	patch->bank = bank;
333 	patch->next = opl3->patch_table[key];
334 	opl3->patch_table[key] = patch;
335 	return patch;
336 }
337 EXPORT_SYMBOL(snd_opl3_find_patch);
338 
339 /*
340  * Clear all patches of the given OPL3 instance
341  */
342 void snd_opl3_clear_patches(struct snd_opl3 *opl3)
343 {
344 	int i;
345 	for (i = 0; i <  OPL3_PATCH_HASH_SIZE; i++) {
346 		struct fm_patch *patch, *next;
347 		for (patch = opl3->patch_table[i]; patch; patch = next) {
348 			next = patch->next;
349 			kfree(patch);
350 		}
351 	}
352 	memset(opl3->patch_table, 0, sizeof(opl3->patch_table));
353 }
354 #endif /* OPL3_SUPPORT_SYNTH */
355 
356 /* ------------------------------ */
357 
358 void snd_opl3_reset(struct snd_opl3 * opl3)
359 {
360 	unsigned short opl3_reg;
361 
362 	unsigned short reg_side;
363 	unsigned char voice_offset;
364 
365 	int max_voices, i;
366 
367 	max_voices = (opl3->hardware < OPL3_HW_OPL3) ?
368 		MAX_OPL2_VOICES : MAX_OPL3_VOICES;
369 
370 	for (i = 0; i < max_voices; i++) {
371 		/* Get register array side and offset of voice */
372 		if (i < MAX_OPL2_VOICES) {
373 			/* Left register block for voices 0 .. 8 */
374 			reg_side = OPL3_LEFT;
375 			voice_offset = i;
376 		} else {
377 			/* Right register block for voices 9 .. 17 */
378 			reg_side = OPL3_RIGHT;
379 			voice_offset = i - MAX_OPL2_VOICES;
380 		}
381 		opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][0]);
382 		opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 1 volume */
383 		opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][1]);
384 		opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 2 volume */
385 
386 		opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
387 		opl3->command(opl3, opl3_reg, 0x00);	/* Note off */
388 	}
389 
390 	opl3->max_voices = MAX_OPL2_VOICES;
391 	opl3->fm_mode = SNDRV_DM_FM_MODE_OPL2;
392 
393 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_TEST, OPL3_ENABLE_WAVE_SELECT);
394 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, 0x00);	/* Melodic mode */
395 	opl3->rhythm = 0;
396 }
397 
398 EXPORT_SYMBOL(snd_opl3_reset);
399 
400 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note)
401 {
402 	unsigned short reg_side;
403 	unsigned char voice_offset;
404 
405 	unsigned short opl3_reg;
406 	unsigned char reg_val;
407 
408 	/* Voices 0 -  8 in OPL2 mode */
409 	/* Voices 0 - 17 in OPL3 mode */
410 	if (note->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
411 			    MAX_OPL3_VOICES : MAX_OPL2_VOICES))
412 		return -EINVAL;
413 
414 	/* Get register array side and offset of voice */
415 	if (note->voice < MAX_OPL2_VOICES) {
416 		/* Left register block for voices 0 .. 8 */
417 		reg_side = OPL3_LEFT;
418 		voice_offset = note->voice;
419 	} else {
420 		/* Right register block for voices 9 .. 17 */
421 		reg_side = OPL3_RIGHT;
422 		voice_offset = note->voice - MAX_OPL2_VOICES;
423 	}
424 
425 	/* Set lower 8 bits of note frequency */
426 	reg_val = (unsigned char) note->fnum;
427 	opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
428 	opl3->command(opl3, opl3_reg, reg_val);
429 
430 	reg_val = 0x00;
431 	/* Set output sound flag */
432 	if (note->key_on)
433 		reg_val |= OPL3_KEYON_BIT;
434 	/* Set octave */
435 	reg_val |= (note->octave << 2) & OPL3_BLOCKNUM_MASK;
436 	/* Set higher 2 bits of note frequency */
437 	reg_val |= (unsigned char) (note->fnum >> 8) & OPL3_FNUM_HIGH_MASK;
438 
439 	/* Set OPL3 KEYON_BLOCK register of requested voice */
440 	opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
441 	opl3->command(opl3, opl3_reg, reg_val);
442 
443 	return 0;
444 }
445 
446 
447 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice)
448 {
449 	unsigned short reg_side;
450 	unsigned char op_offset;
451 	unsigned char voice_offset;
452 
453 	unsigned short opl3_reg;
454 	unsigned char reg_val;
455 
456 	/* Only operators 1 and 2 */
457 	if (voice->op > 1)
458 		return -EINVAL;
459 	/* Voices 0 -  8 in OPL2 mode */
460 	/* Voices 0 - 17 in OPL3 mode */
461 	if (voice->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
462 			     MAX_OPL3_VOICES : MAX_OPL2_VOICES))
463 		return -EINVAL;
464 
465 	/* Get register array side and offset of voice */
466 	if (voice->voice < MAX_OPL2_VOICES) {
467 		/* Left register block for voices 0 .. 8 */
468 		reg_side = OPL3_LEFT;
469 		voice_offset = voice->voice;
470 	} else {
471 		/* Right register block for voices 9 .. 17 */
472 		reg_side = OPL3_RIGHT;
473 		voice_offset = voice->voice - MAX_OPL2_VOICES;
474 	}
475 	/* Get register offset of operator */
476 	op_offset = snd_opl3_regmap[voice_offset][voice->op];
477 
478 	reg_val = 0x00;
479 	/* Set amplitude modulation (tremolo) effect */
480 	if (voice->am)
481 		reg_val |= OPL3_TREMOLO_ON;
482 	/* Set vibrato effect */
483 	if (voice->vibrato)
484 		reg_val |= OPL3_VIBRATO_ON;
485 	/* Set sustaining sound phase */
486 	if (voice->do_sustain)
487 		reg_val |= OPL3_SUSTAIN_ON;
488 	/* Set keyboard scaling bit */
489 	if (voice->kbd_scale)
490 		reg_val |= OPL3_KSR;
491 	/* Set harmonic or frequency multiplier */
492 	reg_val |= voice->harmonic & OPL3_MULTIPLE_MASK;
493 
494 	/* Set OPL3 AM_VIB register of requested voice/operator */
495 	opl3_reg = reg_side | (OPL3_REG_AM_VIB + op_offset);
496 	opl3->command(opl3, opl3_reg, reg_val);
497 
498 	/* Set decreasing volume of higher notes */
499 	reg_val = (voice->scale_level << 6) & OPL3_KSL_MASK;
500 	/* Set output volume */
501 	reg_val |= ~voice->volume & OPL3_TOTAL_LEVEL_MASK;
502 
503 	/* Set OPL3 KSL_LEVEL register of requested voice/operator */
504 	opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + op_offset);
505 	opl3->command(opl3, opl3_reg, reg_val);
506 
507 	/* Set attack phase level */
508 	reg_val = (voice->attack << 4) & OPL3_ATTACK_MASK;
509 	/* Set decay phase level */
510 	reg_val |= voice->decay & OPL3_DECAY_MASK;
511 
512 	/* Set OPL3 ATTACK_DECAY register of requested voice/operator */
513 	opl3_reg = reg_side | (OPL3_REG_ATTACK_DECAY + op_offset);
514 	opl3->command(opl3, opl3_reg, reg_val);
515 
516 	/* Set sustain phase level */
517 	reg_val = (voice->sustain << 4) & OPL3_SUSTAIN_MASK;
518 	/* Set release phase level */
519 	reg_val |= voice->release & OPL3_RELEASE_MASK;
520 
521 	/* Set OPL3 SUSTAIN_RELEASE register of requested voice/operator */
522 	opl3_reg = reg_side | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
523 	opl3->command(opl3, opl3_reg, reg_val);
524 
525 	/* Set inter-operator feedback */
526 	reg_val = (voice->feedback << 1) & OPL3_FEEDBACK_MASK;
527 	/* Set inter-operator connection */
528 	if (voice->connection)
529 		reg_val |= OPL3_CONNECTION_BIT;
530 	/* OPL-3 only */
531 	if (opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) {
532 		if (voice->left)
533 			reg_val |= OPL3_VOICE_TO_LEFT;
534 		if (voice->right)
535 			reg_val |= OPL3_VOICE_TO_RIGHT;
536 	}
537 	/* Feedback/connection bits are applicable to voice */
538 	opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
539 	opl3->command(opl3, opl3_reg, reg_val);
540 
541 	/* Select waveform */
542 	reg_val = voice->waveform & OPL3_WAVE_SELECT_MASK;
543 	opl3_reg = reg_side | (OPL3_REG_WAVE_SELECT + op_offset);
544 	opl3->command(opl3, opl3_reg, reg_val);
545 
546 	return 0;
547 }
548 
549 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params)
550 {
551 	unsigned char reg_val;
552 
553 	reg_val = 0x00;
554 	/* Set keyboard split method */
555 	if (params->kbd_split)
556 		reg_val |= OPL3_KEYBOARD_SPLIT;
557 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_KBD_SPLIT, reg_val);
558 
559 	reg_val = 0x00;
560 	/* Set amplitude modulation (tremolo) depth */
561 	if (params->am_depth)
562 		reg_val |= OPL3_TREMOLO_DEPTH;
563 	/* Set vibrato depth */
564 	if (params->vib_depth)
565 		reg_val |= OPL3_VIBRATO_DEPTH;
566 	/* Set percussion mode */
567 	if (params->rhythm) {
568 		reg_val |= OPL3_PERCUSSION_ENABLE;
569 		opl3->rhythm = 1;
570 	} else {
571 		opl3->rhythm = 0;
572 	}
573 	/* Play percussion instruments */
574 	if (params->bass)
575 		reg_val |= OPL3_BASSDRUM_ON;
576 	if (params->snare)
577 		reg_val |= OPL3_SNAREDRUM_ON;
578 	if (params->tomtom)
579 		reg_val |= OPL3_TOMTOM_ON;
580 	if (params->cymbal)
581 		reg_val |= OPL3_CYMBAL_ON;
582 	if (params->hihat)
583 		reg_val |= OPL3_HIHAT_ON;
584 
585 	opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, reg_val);
586 	return 0;
587 }
588 
589 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode)
590 {
591 	if ((mode == SNDRV_DM_FM_MODE_OPL3) && (opl3->hardware < OPL3_HW_OPL3))
592 		return -EINVAL;
593 
594 	opl3->fm_mode = mode;
595 	if (opl3->hardware >= OPL3_HW_OPL3)
596 		opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, 0x00);	/* Clear 4-op connections */
597 
598 	return 0;
599 }
600 
601 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection)
602 {
603 	unsigned char reg_val;
604 
605 	/* OPL-3 only */
606 	if (opl3->fm_mode != SNDRV_DM_FM_MODE_OPL3)
607 		return -EINVAL;
608 
609 	reg_val = connection & (OPL3_RIGHT_4OP_0 | OPL3_RIGHT_4OP_1 | OPL3_RIGHT_4OP_2 |
610 				OPL3_LEFT_4OP_0 | OPL3_LEFT_4OP_1 | OPL3_LEFT_4OP_2);
611 	/* Set 4-op connections */
612 	opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, reg_val);
613 
614 	return 0;
615 }
616 
617