1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Virtual master and follower controls
4 *
5 * Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
6 */
7
8#include <linux/slab.h>
9#include <linux/export.h>
10#include <sound/core.h>
11#include <sound/control.h>
12#include <sound/tlv.h>
13
14/*
15 * a subset of information returned via ctl info callback
16 */
17struct link_ctl_info {
18 snd_ctl_elem_type_t type; /* value type */
19 int count; /* item count */
20 int min_val, max_val; /* min, max values */
21};
22
23/*
24 * link master - this contains a list of follower controls that are
25 * identical types, i.e. info returns the same value type and value
26 * ranges, but may have different number of counts.
27 *
28 * The master control is so far only mono volume/switch for simplicity.
29 * The same value will be applied to all followers.
30 */
31struct link_master {
32 struct list_head followers;
33 struct link_ctl_info info;
34 int val; /* the master value */
35 unsigned int tlv[4];
36 void (*hook)(void *private_data, int);
37 void *hook_private_data;
38};
39
40/*
41 * link follower - this contains a follower control element
42 *
43 * It fakes the control callbacks with additional attenuation by the
44 * master control. A follower may have either one or two channels.
45 */
46
47struct link_follower {
48 struct list_head list;
49 struct link_master *master;
50 struct link_ctl_info info;
51 int vals[2]; /* current values */
52 unsigned int flags;
53 struct snd_kcontrol *kctl; /* original kcontrol pointer */
54 struct snd_kcontrol follower; /* the copy of original control entry */
55};
56
57static int follower_update(struct link_follower *follower)
58{
59 struct snd_ctl_elem_value *uctl;
60 int err, ch;
61
62 uctl = kzalloc(size: sizeof(*uctl), GFP_KERNEL);
63 if (!uctl)
64 return -ENOMEM;
65 uctl->id = follower->follower.id;
66 err = follower->follower.get(&follower->follower, uctl);
67 if (err < 0)
68 goto error;
69 for (ch = 0; ch < follower->info.count; ch++)
70 follower->vals[ch] = uctl->value.integer.value[ch];
71 error:
72 kfree(objp: uctl);
73 return err < 0 ? err : 0;
74}
75
76/* get the follower ctl info and save the initial values */
77static int follower_init(struct link_follower *follower)
78{
79 struct snd_ctl_elem_info *uinfo;
80 int err;
81
82 if (follower->info.count) {
83 /* already initialized */
84 if (follower->flags & SND_CTL_FOLLOWER_NEED_UPDATE)
85 return follower_update(follower);
86 return 0;
87 }
88
89 uinfo = kmalloc(size: sizeof(*uinfo), GFP_KERNEL);
90 if (!uinfo)
91 return -ENOMEM;
92 uinfo->id = follower->follower.id;
93 err = follower->follower.info(&follower->follower, uinfo);
94 if (err < 0) {
95 kfree(objp: uinfo);
96 return err;
97 }
98 follower->info.type = uinfo->type;
99 follower->info.count = uinfo->count;
100 if (follower->info.count > 2 ||
101 (follower->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
102 follower->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
103 pr_err("ALSA: vmaster: invalid follower element\n");
104 kfree(objp: uinfo);
105 return -EINVAL;
106 }
107 follower->info.min_val = uinfo->value.integer.min;
108 follower->info.max_val = uinfo->value.integer.max;
109 kfree(objp: uinfo);
110
111 return follower_update(follower);
112}
113
114/* initialize master volume */
115static int master_init(struct link_master *master)
116{
117 struct link_follower *follower;
118
119 if (master->info.count)
120 return 0; /* already initialized */
121
122 list_for_each_entry(follower, &master->followers, list) {
123 int err = follower_init(follower);
124 if (err < 0)
125 return err;
126 master->info = follower->info;
127 master->info.count = 1; /* always mono */
128 /* set full volume as default (= no attenuation) */
129 master->val = master->info.max_val;
130 if (master->hook)
131 master->hook(master->hook_private_data, master->val);
132 return 1;
133 }
134 return -ENOENT;
135}
136
137static int follower_get_val(struct link_follower *follower,
138 struct snd_ctl_elem_value *ucontrol)
139{
140 int err, ch;
141
142 err = follower_init(follower);
143 if (err < 0)
144 return err;
145 for (ch = 0; ch < follower->info.count; ch++)
146 ucontrol->value.integer.value[ch] = follower->vals[ch];
147 return 0;
148}
149
150static int follower_put_val(struct link_follower *follower,
151 struct snd_ctl_elem_value *ucontrol)
152{
153 int err, ch, vol;
154
155 err = master_init(master: follower->master);
156 if (err < 0)
157 return err;
158
159 switch (follower->info.type) {
160 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
161 for (ch = 0; ch < follower->info.count; ch++)
162 ucontrol->value.integer.value[ch] &=
163 !!follower->master->val;
164 break;
165 case SNDRV_CTL_ELEM_TYPE_INTEGER:
166 for (ch = 0; ch < follower->info.count; ch++) {
167 /* max master volume is supposed to be 0 dB */
168 vol = ucontrol->value.integer.value[ch];
169 vol += follower->master->val - follower->master->info.max_val;
170 if (vol < follower->info.min_val)
171 vol = follower->info.min_val;
172 else if (vol > follower->info.max_val)
173 vol = follower->info.max_val;
174 ucontrol->value.integer.value[ch] = vol;
175 }
176 break;
177 }
178 return follower->follower.put(&follower->follower, ucontrol);
179}
180
181/*
182 * ctl callbacks for followers
183 */
184static int follower_info(struct snd_kcontrol *kcontrol,
185 struct snd_ctl_elem_info *uinfo)
186{
187 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
188 return follower->follower.info(&follower->follower, uinfo);
189}
190
191static int follower_get(struct snd_kcontrol *kcontrol,
192 struct snd_ctl_elem_value *ucontrol)
193{
194 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
195 return follower_get_val(follower, ucontrol);
196}
197
198static int follower_put(struct snd_kcontrol *kcontrol,
199 struct snd_ctl_elem_value *ucontrol)
200{
201 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
202 int err, ch, changed = 0;
203
204 err = follower_init(follower);
205 if (err < 0)
206 return err;
207 for (ch = 0; ch < follower->info.count; ch++) {
208 if (follower->vals[ch] != ucontrol->value.integer.value[ch]) {
209 changed = 1;
210 follower->vals[ch] = ucontrol->value.integer.value[ch];
211 }
212 }
213 if (!changed)
214 return 0;
215 err = follower_put_val(follower, ucontrol);
216 if (err < 0)
217 return err;
218 return 1;
219}
220
221static int follower_tlv_cmd(struct snd_kcontrol *kcontrol,
222 int op_flag, unsigned int size,
223 unsigned int __user *tlv)
224{
225 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
226 /* FIXME: this assumes that the max volume is 0 dB */
227 return follower->follower.tlv.c(&follower->follower, op_flag, size, tlv);
228}
229
230static void follower_free(struct snd_kcontrol *kcontrol)
231{
232 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
233 if (follower->follower.private_free)
234 follower->follower.private_free(&follower->follower);
235 if (follower->master)
236 list_del(entry: &follower->list);
237 kfree(objp: follower);
238}
239
240/*
241 * Add a follower control to the group with the given master control
242 *
243 * All followers must be the same type (returning the same information
244 * via info callback). The function doesn't check it, so it's your
245 * responsibility.
246 *
247 * Also, some additional limitations:
248 * - at most two channels
249 * - logarithmic volume control (dB level), no linear volume
250 * - master can only attenuate the volume, no gain
251 */
252int _snd_ctl_add_follower(struct snd_kcontrol *master,
253 struct snd_kcontrol *follower,
254 unsigned int flags)
255{
256 struct link_master *master_link = snd_kcontrol_chip(master);
257 struct link_follower *srec;
258
259 srec = kzalloc(struct_size(srec, follower.vd, follower->count),
260 GFP_KERNEL);
261 if (!srec)
262 return -ENOMEM;
263 srec->kctl = follower;
264 srec->follower = *follower;
265 memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd));
266 srec->master = master_link;
267 srec->flags = flags;
268
269 /* override callbacks */
270 follower->info = follower_info;
271 follower->get = follower_get;
272 follower->put = follower_put;
273 if (follower->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
274 follower->tlv.c = follower_tlv_cmd;
275 follower->private_data = srec;
276 follower->private_free = follower_free;
277
278 list_add_tail(new: &srec->list, head: &master_link->followers);
279 return 0;
280}
281EXPORT_SYMBOL(_snd_ctl_add_follower);
282
283/**
284 * snd_ctl_add_followers - add multiple followers to vmaster
285 * @card: card instance
286 * @master: the target vmaster kcontrol object
287 * @list: NULL-terminated list of name strings of followers to be added
288 *
289 * Adds the multiple follower kcontrols with the given names.
290 * Returns 0 for success or a negative error code.
291 */
292int snd_ctl_add_followers(struct snd_card *card, struct snd_kcontrol *master,
293 const char * const *list)
294{
295 struct snd_kcontrol *follower;
296 int err;
297
298 for (; *list; list++) {
299 follower = snd_ctl_find_id_mixer(card, name: *list);
300 if (follower) {
301 err = snd_ctl_add_follower(master, follower);
302 if (err < 0)
303 return err;
304 }
305 }
306
307 return 0;
308}
309EXPORT_SYMBOL_GPL(snd_ctl_add_followers);
310
311/*
312 * ctl callbacks for master controls
313 */
314static int master_info(struct snd_kcontrol *kcontrol,
315 struct snd_ctl_elem_info *uinfo)
316{
317 struct link_master *master = snd_kcontrol_chip(kcontrol);
318 int ret;
319
320 ret = master_init(master);
321 if (ret < 0)
322 return ret;
323 uinfo->type = master->info.type;
324 uinfo->count = master->info.count;
325 uinfo->value.integer.min = master->info.min_val;
326 uinfo->value.integer.max = master->info.max_val;
327 return 0;
328}
329
330static int master_get(struct snd_kcontrol *kcontrol,
331 struct snd_ctl_elem_value *ucontrol)
332{
333 struct link_master *master = snd_kcontrol_chip(kcontrol);
334 int err = master_init(master);
335 if (err < 0)
336 return err;
337 ucontrol->value.integer.value[0] = master->val;
338 return 0;
339}
340
341static int sync_followers(struct link_master *master, int old_val, int new_val)
342{
343 struct link_follower *follower;
344 struct snd_ctl_elem_value *uval;
345
346 uval = kmalloc(size: sizeof(*uval), GFP_KERNEL);
347 if (!uval)
348 return -ENOMEM;
349 list_for_each_entry(follower, &master->followers, list) {
350 master->val = old_val;
351 uval->id = follower->follower.id;
352 follower_get_val(follower, ucontrol: uval);
353 master->val = new_val;
354 follower_put_val(follower, ucontrol: uval);
355 }
356 kfree(objp: uval);
357 return 0;
358}
359
360static int master_put(struct snd_kcontrol *kcontrol,
361 struct snd_ctl_elem_value *ucontrol)
362{
363 struct link_master *master = snd_kcontrol_chip(kcontrol);
364 int err, new_val, old_val;
365 bool first_init;
366
367 err = master_init(master);
368 if (err < 0)
369 return err;
370 first_init = err;
371 old_val = master->val;
372 new_val = ucontrol->value.integer.value[0];
373 if (new_val == old_val)
374 return 0;
375
376 err = sync_followers(master, old_val, new_val);
377 if (err < 0)
378 return err;
379 if (master->hook && !first_init)
380 master->hook(master->hook_private_data, master->val);
381 return 1;
382}
383
384static void master_free(struct snd_kcontrol *kcontrol)
385{
386 struct link_master *master = snd_kcontrol_chip(kcontrol);
387 struct link_follower *follower, *n;
388
389 /* free all follower links and retore the original follower kctls */
390 list_for_each_entry_safe(follower, n, &master->followers, list) {
391 struct snd_kcontrol *sctl = follower->kctl;
392 struct list_head olist = sctl->list;
393 memcpy(sctl, &follower->follower, sizeof(*sctl));
394 memcpy(sctl->vd, follower->follower.vd,
395 sctl->count * sizeof(*sctl->vd));
396 sctl->list = olist; /* keep the current linked-list */
397 kfree(objp: follower);
398 }
399 kfree(objp: master);
400}
401
402
403/**
404 * snd_ctl_make_virtual_master - Create a virtual master control
405 * @name: name string of the control element to create
406 * @tlv: optional TLV int array for dB information
407 *
408 * Creates a virtual master control with the given name string.
409 *
410 * After creating a vmaster element, you can add the follower controls
411 * via snd_ctl_add_follower() or snd_ctl_add_follower_uncached().
412 *
413 * The optional argument @tlv can be used to specify the TLV information
414 * for dB scale of the master control. It should be a single element
415 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
416 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
417 *
418 * Return: The created control element, or %NULL for errors (ENOMEM).
419 */
420struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
421 const unsigned int *tlv)
422{
423 struct link_master *master;
424 struct snd_kcontrol *kctl;
425 struct snd_kcontrol_new knew;
426
427 memset(&knew, 0, sizeof(knew));
428 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
429 knew.name = name;
430 knew.info = master_info;
431
432 master = kzalloc(size: sizeof(*master), GFP_KERNEL);
433 if (!master)
434 return NULL;
435 INIT_LIST_HEAD(list: &master->followers);
436
437 kctl = snd_ctl_new1(kcontrolnew: &knew, private_data: master);
438 if (!kctl) {
439 kfree(objp: master);
440 return NULL;
441 }
442 /* override some callbacks */
443 kctl->info = master_info;
444 kctl->get = master_get;
445 kctl->put = master_put;
446 kctl->private_free = master_free;
447
448 /* additional (constant) TLV read */
449 if (tlv) {
450 unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
451 if (type == SNDRV_CTL_TLVT_DB_SCALE ||
452 type == SNDRV_CTL_TLVT_DB_MINMAX ||
453 type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
454 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
455 memcpy(master->tlv, tlv, sizeof(master->tlv));
456 kctl->tlv.p = master->tlv;
457 }
458 }
459
460 return kctl;
461}
462EXPORT_SYMBOL(snd_ctl_make_virtual_master);
463
464/**
465 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
466 * @kcontrol: vmaster kctl element
467 * @hook: the hook function
468 * @private_data: the private_data pointer to be saved
469 *
470 * Adds the given hook to the vmaster control element so that it's called
471 * at each time when the value is changed.
472 *
473 * Return: Zero.
474 */
475int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
476 void (*hook)(void *private_data, int),
477 void *private_data)
478{
479 struct link_master *master = snd_kcontrol_chip(kcontrol);
480 master->hook = hook;
481 master->hook_private_data = private_data;
482 return 0;
483}
484EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
485
486/**
487 * snd_ctl_sync_vmaster - Sync the vmaster followers and hook
488 * @kcontrol: vmaster kctl element
489 * @hook_only: sync only the hook
490 *
491 * Forcibly call the put callback of each follower and call the hook function
492 * to synchronize with the current value of the given vmaster element.
493 * NOP when NULL is passed to @kcontrol.
494 */
495void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
496{
497 struct link_master *master;
498 bool first_init = false;
499
500 if (!kcontrol)
501 return;
502 master = snd_kcontrol_chip(kcontrol);
503 if (!hook_only) {
504 int err = master_init(master);
505 if (err < 0)
506 return;
507 first_init = err;
508 err = sync_followers(master, old_val: master->val, new_val: master->val);
509 if (err < 0)
510 return;
511 }
512
513 if (master->hook && !first_init)
514 master->hook(master->hook_private_data, master->val);
515}
516EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
517
518/**
519 * snd_ctl_apply_vmaster_followers - Apply function to each vmaster follower
520 * @kctl: vmaster kctl element
521 * @func: function to apply
522 * @arg: optional function argument
523 *
524 * Apply the function @func to each follower kctl of the given vmaster kctl.
525 *
526 * Return: 0 if successful, or a negative error code
527 */
528int snd_ctl_apply_vmaster_followers(struct snd_kcontrol *kctl,
529 int (*func)(struct snd_kcontrol *vfollower,
530 struct snd_kcontrol *follower,
531 void *arg),
532 void *arg)
533{
534 struct link_master *master;
535 struct link_follower *follower;
536 int err;
537
538 master = snd_kcontrol_chip(kctl);
539 err = master_init(master);
540 if (err < 0)
541 return err;
542 list_for_each_entry(follower, &master->followers, list) {
543 err = func(follower->kctl, &follower->follower, arg);
544 if (err < 0)
545 return err;
546 }
547
548 return 0;
549}
550EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);
551

source code of linux/sound/core/vmaster.c