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