301acb6b9cf9af792ddc33160989dcb8dbcc8769
[linux-2.6.git] / sound / drivers / opl3 / opl3_synth.c
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 <sound/opl3.h>
24 #include <sound/asound_fm.h>
25
26 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
27 #define OPL3_SUPPORT_SYNTH
28 #endif
29
30 /*
31  *    There is 18 possible 2 OP voices
32  *      (9 in the left and 9 in the right).
33  *      The first OP is the modulator and 2nd is the carrier.
34  *
35  *      The first three voices in the both sides may be connected
36  *      with another voice to a 4 OP voice. For example voice 0
37  *      can be connected with voice 3. The operators of voice 3 are
38  *      used as operators 3 and 4 of the new 4 OP voice.
39  *      In this case the 2 OP voice number 0 is the 'first half' and
40  *      voice 3 is the second.
41  */
42
43
44 /*
45  *    Register offset table for OPL2/3 voices,
46  *    OPL2 / one OPL3 register array side only
47  */
48
49 char snd_opl3_regmap[MAX_OPL2_VOICES][4] =
50 {
51 /*        OP1   OP2   OP3   OP4         */
52 /*       ------------------------       */
53         { 0x00, 0x03, 0x08, 0x0b },
54         { 0x01, 0x04, 0x09, 0x0c },
55         { 0x02, 0x05, 0x0a, 0x0d },
56
57         { 0x08, 0x0b, 0x00, 0x00 },
58         { 0x09, 0x0c, 0x00, 0x00 },
59         { 0x0a, 0x0d, 0x00, 0x00 },
60
61         { 0x10, 0x13, 0x00, 0x00 },     /* used by percussive voices */
62         { 0x11, 0x14, 0x00, 0x00 },     /* if the percussive mode */
63         { 0x12, 0x15, 0x00, 0x00 }      /* is selected (only left reg block) */
64 };
65
66 EXPORT_SYMBOL(snd_opl3_regmap);
67
68 /*
69  * prototypes
70  */
71 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note);
72 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice);
73 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params);
74 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode);
75 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection);
76
77 /* ------------------------------ */
78
79 /*
80  * open the device exclusively
81  */
82 int snd_opl3_open(struct snd_hwdep * hw, struct file *file)
83 {
84         return 0;
85 }
86
87 /*
88  * ioctl for hwdep device:
89  */
90 int snd_opl3_ioctl(struct snd_hwdep * hw, struct file *file,
91                    unsigned int cmd, unsigned long arg)
92 {
93         struct snd_opl3 *opl3 = hw->private_data;
94         void __user *argp = (void __user *)arg;
95
96         if (snd_BUG_ON(!opl3))
97                 return -EINVAL;
98
99         switch (cmd) {
100                 /* get information */
101         case SNDRV_DM_FM_IOCTL_INFO:
102                 {
103                         struct snd_dm_fm_info info;
104
105                         info.fm_mode = opl3->fm_mode;
106                         info.rhythm = opl3->rhythm;
107                         if (copy_to_user(argp, &info, sizeof(struct snd_dm_fm_info)))
108                                 return -EFAULT;
109                         return 0;
110                 }
111
112         case SNDRV_DM_FM_IOCTL_RESET:
113 #ifdef CONFIG_SND_OSSEMUL
114         case SNDRV_DM_FM_OSS_IOCTL_RESET:
115 #endif
116                 snd_opl3_reset(opl3);
117                 return 0;
118
119         case SNDRV_DM_FM_IOCTL_PLAY_NOTE:
120 #ifdef CONFIG_SND_OSSEMUL
121         case SNDRV_DM_FM_OSS_IOCTL_PLAY_NOTE:
122 #endif
123                 {
124                         struct snd_dm_fm_note note;
125                         if (copy_from_user(&note, argp, sizeof(struct snd_dm_fm_note)))
126                                 return -EFAULT;
127                         return snd_opl3_play_note(opl3, &note);
128                 }
129
130         case SNDRV_DM_FM_IOCTL_SET_VOICE:
131 #ifdef CONFIG_SND_OSSEMUL
132         case SNDRV_DM_FM_OSS_IOCTL_SET_VOICE:
133 #endif
134                 {
135                         struct snd_dm_fm_voice voice;
136                         if (copy_from_user(&voice, argp, sizeof(struct snd_dm_fm_voice)))
137                                 return -EFAULT;
138                         return snd_opl3_set_voice(opl3, &voice);
139                 }
140
141         case SNDRV_DM_FM_IOCTL_SET_PARAMS:
142 #ifdef CONFIG_SND_OSSEMUL
143         case SNDRV_DM_FM_OSS_IOCTL_SET_PARAMS:
144 #endif
145                 {
146                         struct snd_dm_fm_params params;
147                         if (copy_from_user(&params, argp, sizeof(struct snd_dm_fm_params)))
148                                 return -EFAULT;
149                         return snd_opl3_set_params(opl3, &params);
150                 }
151
152         case SNDRV_DM_FM_IOCTL_SET_MODE:
153 #ifdef CONFIG_SND_OSSEMUL
154         case SNDRV_DM_FM_OSS_IOCTL_SET_MODE:
155 #endif
156                 return snd_opl3_set_mode(opl3, (int) arg);
157
158         case SNDRV_DM_FM_IOCTL_SET_CONNECTION:
159 #ifdef CONFIG_SND_OSSEMUL
160         case SNDRV_DM_FM_OSS_IOCTL_SET_OPL:
161 #endif
162                 return snd_opl3_set_connection(opl3, (int) arg);
163
164 #ifdef OPL3_SUPPORT_SYNTH
165         case SNDRV_DM_FM_IOCTL_CLEAR_PATCHES:
166                 snd_opl3_clear_patches(opl3);
167                 return 0;
168 #endif
169
170 #ifdef CONFIG_SND_DEBUG
171         default:
172                 snd_printk(KERN_WARNING "unknown IOCTL: 0x%x\n", cmd);
173 #endif
174         }
175         return -ENOTTY;
176 }
177
178 /*
179  * close the device
180  */
181 int snd_opl3_release(struct snd_hwdep * hw, struct file *file)
182 {
183         struct snd_opl3 *opl3 = hw->private_data;
184
185         snd_opl3_reset(opl3);
186         return 0;
187 }
188
189 #ifdef OPL3_SUPPORT_SYNTH
190 /*
191  * write the device - load patches
192  */
193 long snd_opl3_write(struct snd_hwdep *hw, const char __user *buf, long count,
194                     loff_t *offset)
195 {
196         struct snd_opl3 *opl3 = hw->private_data;
197         long result = 0;
198         int err = 0;
199         struct sbi_patch inst;
200
201         while (count >= sizeof(inst)) {
202                 unsigned char type;
203                 if (copy_from_user(&inst, buf, sizeof(inst)))
204                         return -EFAULT;
205                 if (!memcmp(inst.key, FM_KEY_SBI, 4) ||
206                     !memcmp(inst.key, FM_KEY_2OP, 4))
207                         type = FM_PATCH_OPL2;
208                 else if (!memcmp(inst.key, FM_KEY_4OP, 4))
209                         type = FM_PATCH_OPL3;
210                 else /* invalid type */
211                         break;
212                 err = snd_opl3_load_patch(opl3, inst.prog, inst.bank, type,
213                                           inst.name, inst.extension,
214                                           inst.data);
215                 if (err < 0)
216                         break;
217                 result += sizeof(inst);
218                 count -= sizeof(inst);
219         }
220         return result > 0 ? result : err;
221 }
222
223
224 /*
225  * Patch management
226  */
227
228 /* offsets for SBI params */
229 #define AM_VIB          0
230 #define KSL_LEVEL       2
231 #define ATTACK_DECAY    4
232 #define SUSTAIN_RELEASE 6
233 #define WAVE_SELECT     8
234
235 /* offset for SBI instrument */
236 #define CONNECTION      10
237 #define OFFSET_4OP      11
238
239 /*
240  * load a patch, obviously.
241  *
242  * loaded on the given program and bank numbers with the given type
243  * (FM_PATCH_OPLx).
244  * data is the pointer of SBI record _without_ header (key and name).
245  * name is the name string of the patch.
246  * ext is the extension data of 7 bytes long (stored in name of SBI
247  * data up to offset 25), or NULL to skip.
248  * return 0 if successful or a negative error code.
249  */
250 int snd_opl3_load_patch(struct snd_opl3 *opl3,
251                         int prog, int bank, int type,
252                         const char *name,
253                         const unsigned char *ext,
254                         const unsigned char *data)
255 {
256         struct fm_patch *patch;
257         int i;
258
259         patch = snd_opl3_find_patch(opl3, prog, bank, 1);
260         if (!patch)
261                 return -ENOMEM;
262
263         patch->type = type;
264
265         for (i = 0; i < 2; i++) {
266                 patch->inst.op[i].am_vib = data[AM_VIB + i];
267                 patch->inst.op[i].ksl_level = data[KSL_LEVEL + i];
268                 patch->inst.op[i].attack_decay = data[ATTACK_DECAY + i];
269                 patch->inst.op[i].sustain_release = data[SUSTAIN_RELEASE + i];
270                 patch->inst.op[i].wave_select = data[WAVE_SELECT + i];
271         }
272         patch->inst.feedback_connection[0] = data[CONNECTION];
273
274         if (type == FM_PATCH_OPL3) {
275                 for (i = 0; i < 2; i++) {
276                         patch->inst.op[i+2].am_vib =
277                                 data[OFFSET_4OP + AM_VIB + i];
278                         patch->inst.op[i+2].ksl_level =
279                                 data[OFFSET_4OP + KSL_LEVEL + i];
280                         patch->inst.op[i+2].attack_decay =
281                                 data[OFFSET_4OP + ATTACK_DECAY + i];
282                         patch->inst.op[i+2].sustain_release =
283                                 data[OFFSET_4OP + SUSTAIN_RELEASE + i];
284                         patch->inst.op[i+2].wave_select =
285                                 data[OFFSET_4OP + WAVE_SELECT + i];
286                 }
287                 patch->inst.feedback_connection[1] =
288                         data[OFFSET_4OP + CONNECTION];
289         }
290
291         if (ext) {
292                 patch->inst.echo_delay = ext[0];
293                 patch->inst.echo_atten = ext[1];
294                 patch->inst.chorus_spread = ext[2];
295                 patch->inst.trnsps = ext[3];
296                 patch->inst.fix_dur = ext[4];
297                 patch->inst.modes = ext[5];
298                 patch->inst.fix_key = ext[6];
299         }
300
301         if (name)
302                 strlcpy(patch->name, name, sizeof(patch->name));
303
304         return 0;
305 }
306 EXPORT_SYMBOL(snd_opl3_load_patch);
307
308 /*
309  * find a patch with the given program and bank numbers, returns its pointer
310  * if no matching patch is found and create_patch is set, it creates a
311  * new patch object.
312  */
313 struct fm_patch *snd_opl3_find_patch(struct snd_opl3 *opl3, int prog, int bank,
314                                      int create_patch)
315 {
316         /* pretty dumb hash key */
317         unsigned int key = (prog + bank) % OPL3_PATCH_HASH_SIZE;
318         struct fm_patch *patch;
319
320         for (patch = opl3->patch_table[key]; patch; patch = patch->next) {
321                 if (patch->prog == prog && patch->bank == bank)
322                         return patch;
323         }
324         if (!create_patch)
325                 return NULL;
326
327         patch = kzalloc(sizeof(*patch), GFP_KERNEL);
328         if (!patch)
329                 return NULL;
330         patch->prog = prog;
331         patch->bank = bank;
332         patch->next = opl3->patch_table[key];
333         opl3->patch_table[key] = patch;
334         return patch;
335 }
336 EXPORT_SYMBOL(snd_opl3_find_patch);
337
338 /*
339  * Clear all patches of the given OPL3 instance
340  */
341 void snd_opl3_clear_patches(struct snd_opl3 *opl3)
342 {
343         int i;
344         for (i = 0; i <  OPL3_PATCH_HASH_SIZE; i++) {
345                 struct fm_patch *patch, *next;
346                 for (patch = opl3->patch_table[i]; patch; patch = next) {
347                         next = patch->next;
348                         kfree(patch);
349                 }
350         }
351         memset(opl3->patch_table, 0, sizeof(opl3->patch_table));
352 }
353 #endif /* OPL3_SUPPORT_SYNTH */
354
355 /* ------------------------------ */
356
357 void snd_opl3_reset(struct snd_opl3 * opl3)
358 {
359         unsigned short opl3_reg;
360
361         unsigned short reg_side;
362         unsigned char voice_offset;
363
364         int max_voices, i;
365
366         max_voices = (opl3->hardware < OPL3_HW_OPL3) ?
367                 MAX_OPL2_VOICES : MAX_OPL3_VOICES;
368
369         for (i = 0; i < max_voices; i++) {
370                 /* Get register array side and offset of voice */
371                 if (i < MAX_OPL2_VOICES) {
372                         /* Left register block for voices 0 .. 8 */
373                         reg_side = OPL3_LEFT;
374                         voice_offset = i;
375                 } else {
376                         /* Right register block for voices 9 .. 17 */
377                         reg_side = OPL3_RIGHT;
378                         voice_offset = i - MAX_OPL2_VOICES;
379                 }
380                 opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][0]);
381                 opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 1 volume */
382                 opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][1]);
383                 opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 2 volume */
384
385                 opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
386                 opl3->command(opl3, opl3_reg, 0x00);    /* Note off */
387         }
388
389         opl3->max_voices = MAX_OPL2_VOICES;
390         opl3->fm_mode = SNDRV_DM_FM_MODE_OPL2;
391
392         opl3->command(opl3, OPL3_LEFT | OPL3_REG_TEST, OPL3_ENABLE_WAVE_SELECT);
393         opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, 0x00);     /* Melodic mode */
394         opl3->rhythm = 0;
395 }
396
397 EXPORT_SYMBOL(snd_opl3_reset);
398
399 static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note)
400 {
401         unsigned short reg_side;
402         unsigned char voice_offset;
403
404         unsigned short opl3_reg;
405         unsigned char reg_val;
406
407         /* Voices 0 -  8 in OPL2 mode */
408         /* Voices 0 - 17 in OPL3 mode */
409         if (note->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
410                             MAX_OPL3_VOICES : MAX_OPL2_VOICES))
411                 return -EINVAL;
412
413         /* Get register array side and offset of voice */
414         if (note->voice < MAX_OPL2_VOICES) {
415                 /* Left register block for voices 0 .. 8 */
416                 reg_side = OPL3_LEFT;
417                 voice_offset = note->voice;
418         } else {
419                 /* Right register block for voices 9 .. 17 */
420                 reg_side = OPL3_RIGHT;
421                 voice_offset = note->voice - MAX_OPL2_VOICES;
422         }
423
424         /* Set lower 8 bits of note frequency */
425         reg_val = (unsigned char) note->fnum;
426         opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
427         opl3->command(opl3, opl3_reg, reg_val);
428         
429         reg_val = 0x00;
430         /* Set output sound flag */
431         if (note->key_on)
432                 reg_val |= OPL3_KEYON_BIT;
433         /* Set octave */
434         reg_val |= (note->octave << 2) & OPL3_BLOCKNUM_MASK;
435         /* Set higher 2 bits of note frequency */
436         reg_val |= (unsigned char) (note->fnum >> 8) & OPL3_FNUM_HIGH_MASK;
437
438         /* Set OPL3 KEYON_BLOCK register of requested voice */ 
439         opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
440         opl3->command(opl3, opl3_reg, reg_val);
441
442         return 0;
443 }
444
445
446 static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice)
447 {
448         unsigned short reg_side;
449         unsigned char op_offset;
450         unsigned char voice_offset;
451
452         unsigned short opl3_reg;
453         unsigned char reg_val;
454
455         /* Only operators 1 and 2 */
456         if (voice->op > 1)
457                 return -EINVAL;
458         /* Voices 0 -  8 in OPL2 mode */
459         /* Voices 0 - 17 in OPL3 mode */
460         if (voice->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
461                              MAX_OPL3_VOICES : MAX_OPL2_VOICES))
462                 return -EINVAL;
463
464         /* Get register array side and offset of voice */
465         if (voice->voice < MAX_OPL2_VOICES) {
466                 /* Left register block for voices 0 .. 8 */
467                 reg_side = OPL3_LEFT;
468                 voice_offset = voice->voice;
469         } else {
470                 /* Right register block for voices 9 .. 17 */
471                 reg_side = OPL3_RIGHT;
472                 voice_offset = voice->voice - MAX_OPL2_VOICES;
473         }
474         /* Get register offset of operator */
475         op_offset = snd_opl3_regmap[voice_offset][voice->op];
476
477         reg_val = 0x00;
478         /* Set amplitude modulation (tremolo) effect */
479         if (voice->am)
480                 reg_val |= OPL3_TREMOLO_ON;
481         /* Set vibrato effect */
482         if (voice->vibrato)
483                 reg_val |= OPL3_VIBRATO_ON;
484         /* Set sustaining sound phase */
485         if (voice->do_sustain)
486                 reg_val |= OPL3_SUSTAIN_ON;
487         /* Set keyboard scaling bit */ 
488         if (voice->kbd_scale)
489                 reg_val |= OPL3_KSR;
490         /* Set harmonic or frequency multiplier */
491         reg_val |= voice->harmonic & OPL3_MULTIPLE_MASK;
492
493         /* Set OPL3 AM_VIB register of requested voice/operator */ 
494         opl3_reg = reg_side | (OPL3_REG_AM_VIB + op_offset);
495         opl3->command(opl3, opl3_reg, reg_val);
496
497         /* Set decreasing volume of higher notes */
498         reg_val = (voice->scale_level << 6) & OPL3_KSL_MASK;
499         /* Set output volume */
500         reg_val |= ~voice->volume & OPL3_TOTAL_LEVEL_MASK;
501
502         /* Set OPL3 KSL_LEVEL register of requested voice/operator */ 
503         opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + op_offset);
504         opl3->command(opl3, opl3_reg, reg_val);
505
506         /* Set attack phase level */
507         reg_val = (voice->attack << 4) & OPL3_ATTACK_MASK;
508         /* Set decay phase level */
509         reg_val |= voice->decay & OPL3_DECAY_MASK;
510
511         /* Set OPL3 ATTACK_DECAY register of requested voice/operator */ 
512         opl3_reg = reg_side | (OPL3_REG_ATTACK_DECAY + op_offset);
513         opl3->command(opl3, opl3_reg, reg_val);
514
515         /* Set sustain phase level */
516         reg_val = (voice->sustain << 4) & OPL3_SUSTAIN_MASK;
517         /* Set release phase level */
518         reg_val |= voice->release & OPL3_RELEASE_MASK;
519
520         /* Set OPL3 SUSTAIN_RELEASE register of requested voice/operator */ 
521         opl3_reg = reg_side | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
522         opl3->command(opl3, opl3_reg, reg_val);
523
524         /* Set inter-operator feedback */
525         reg_val = (voice->feedback << 1) & OPL3_FEEDBACK_MASK;
526         /* Set inter-operator connection */
527         if (voice->connection)
528                 reg_val |= OPL3_CONNECTION_BIT;
529         /* OPL-3 only */
530         if (opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) {
531                 if (voice->left)
532                         reg_val |= OPL3_VOICE_TO_LEFT;
533                 if (voice->right)
534                         reg_val |= OPL3_VOICE_TO_RIGHT;
535         }
536         /* Feedback/connection bits are applicable to voice */
537         opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
538         opl3->command(opl3, opl3_reg, reg_val);
539
540         /* Select waveform */
541         reg_val = voice->waveform & OPL3_WAVE_SELECT_MASK;
542         opl3_reg = reg_side | (OPL3_REG_WAVE_SELECT + op_offset);
543         opl3->command(opl3, opl3_reg, reg_val);
544
545         return 0;
546 }
547
548 static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params)
549 {
550         unsigned char reg_val;
551
552         reg_val = 0x00;
553         /* Set keyboard split method */
554         if (params->kbd_split)
555                 reg_val |= OPL3_KEYBOARD_SPLIT;
556         opl3->command(opl3, OPL3_LEFT | OPL3_REG_KBD_SPLIT, reg_val);
557
558         reg_val = 0x00;
559         /* Set amplitude modulation (tremolo) depth */
560         if (params->am_depth)
561                 reg_val |= OPL3_TREMOLO_DEPTH;
562         /* Set vibrato depth */
563         if (params->vib_depth)
564                 reg_val |= OPL3_VIBRATO_DEPTH;
565         /* Set percussion mode */
566         if (params->rhythm) {
567                 reg_val |= OPL3_PERCUSSION_ENABLE;
568                 opl3->rhythm = 1;
569         } else {
570                 opl3->rhythm = 0;
571         }
572         /* Play percussion instruments */
573         if (params->bass)
574                 reg_val |= OPL3_BASSDRUM_ON;
575         if (params->snare)
576                 reg_val |= OPL3_SNAREDRUM_ON;
577         if (params->tomtom)
578                 reg_val |= OPL3_TOMTOM_ON;
579         if (params->cymbal)
580                 reg_val |= OPL3_CYMBAL_ON;
581         if (params->hihat)
582                 reg_val |= OPL3_HIHAT_ON;
583
584         opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, reg_val);
585         return 0;
586 }
587
588 static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode)
589 {
590         if ((mode == SNDRV_DM_FM_MODE_OPL3) && (opl3->hardware < OPL3_HW_OPL3))
591                 return -EINVAL;
592
593         opl3->fm_mode = mode;
594         if (opl3->hardware >= OPL3_HW_OPL3)
595                 opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, 0x00);     /* Clear 4-op connections */
596
597         return 0;
598 }
599
600 static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection)
601 {
602         unsigned char reg_val;
603
604         /* OPL-3 only */
605         if (opl3->fm_mode != SNDRV_DM_FM_MODE_OPL3)
606                 return -EINVAL;
607
608         reg_val = connection & (OPL3_RIGHT_4OP_0 | OPL3_RIGHT_4OP_1 | OPL3_RIGHT_4OP_2 |
609                                 OPL3_LEFT_4OP_0 | OPL3_LEFT_4OP_1 | OPL3_LEFT_4OP_2);
610         /* Set 4-op connections */
611         opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, reg_val);
612
613         return 0;
614 }
615