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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Virtual master and follower controls
4 *
5 * Copyright (c) 2008 by Takashi Iwai <[email protected]>
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 int err, ch;
60 struct snd_ctl_elem_value *uctl __free(kfree) =
61 kzalloc_obj(*uctl);
62
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 return err;
69 for (ch = 0; ch < follower->info.count; ch++)
70 follower->vals[ch] = uctl->value.integer.value[ch];
71 return 0;
72}
73
74/* get the follower ctl info and save the initial values */
75static int follower_init(struct link_follower *follower)
76{
77 int err;
78
79 if (follower->info.count) {
80 /* already initialized */
81 if (follower->flags & SND_CTL_FOLLOWER_NEED_UPDATE)
82 return follower_update(follower);
83 return 0;
84 }
85
86 struct snd_ctl_elem_info *uinfo __free(kfree) =
87 kmalloc_obj(*uinfo);
88 if (!uinfo)
89 return -ENOMEM;
90 uinfo->id = follower->follower.id;
91 err = follower->follower.info(&follower->follower, uinfo);
92 if (err < 0)
93 return err;
94 follower->info.type = uinfo->type;
95 follower->info.count = uinfo->count;
96 if (follower->info.count > 2 ||
97 (follower->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
98 follower->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
99 pr_err("ALSA: vmaster: invalid follower element\n");
100 return -EINVAL;
101 }
102 follower->info.min_val = uinfo->value.integer.min;
103 follower->info.max_val = uinfo->value.integer.max;
104
105 return follower_update(follower);
106}
107
108/* initialize master volume */
109static int master_init(struct link_master *master)
110{
111 struct link_follower *follower;
112
113 if (master->info.count)
114 return 0; /* already initialized */
115
116 list_for_each_entry(follower, &master->followers, list) {
117 int err = follower_init(follower);
118 if (err < 0)
119 return err;
120 master->info = follower->info;
121 master->info.count = 1; /* always mono */
122 /* set full volume as default (= no attenuation) */
123 master->val = master->info.max_val;
124 if (master->hook)
125 master->hook(master->hook_private_data, master->val);
126 return 1;
127 }
128 return -ENOENT;
129}
130
131static int follower_get_val(struct link_follower *follower,
132 struct snd_ctl_elem_value *ucontrol)
133{
134 int err, ch;
135
136 err = follower_init(follower);
137 if (err < 0)
138 return err;
139 for (ch = 0; ch < follower->info.count; ch++)
140 ucontrol->value.integer.value[ch] = follower->vals[ch];
141 return 0;
142}
143
144static int follower_put_val(struct link_follower *follower,
145 struct snd_ctl_elem_value *ucontrol)
146{
147 int err, ch, vol;
148
149 err = master_init(follower->master);
150 if (err < 0)
151 return err;
152
153 switch (follower->info.type) {
154 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
155 for (ch = 0; ch < follower->info.count; ch++)
156 ucontrol->value.integer.value[ch] &=
157 !!follower->master->val;
158 break;
159 case SNDRV_CTL_ELEM_TYPE_INTEGER:
160 for (ch = 0; ch < follower->info.count; ch++) {
161 /* max master volume is supposed to be 0 dB */
162 vol = ucontrol->value.integer.value[ch];
163 vol += follower->master->val - follower->master->info.max_val;
164 if (vol < follower->info.min_val)
165 vol = follower->info.min_val;
166 else if (vol > follower->info.max_val)
167 vol = follower->info.max_val;
168 ucontrol->value.integer.value[ch] = vol;
169 }
170 break;
171 }
172 return follower->follower.put(&follower->follower, ucontrol);
173}
174
175/*
176 * ctl callbacks for followers
177 */
178static int follower_info(struct snd_kcontrol *kcontrol,
179 struct snd_ctl_elem_info *uinfo)
180{
181 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
182 return follower->follower.info(&follower->follower, uinfo);
183}
184
185static int follower_get(struct snd_kcontrol *kcontrol,
186 struct snd_ctl_elem_value *ucontrol)
187{
188 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
189 return follower_get_val(follower, ucontrol);
190}
191
192static int follower_put(struct snd_kcontrol *kcontrol,
193 struct snd_ctl_elem_value *ucontrol)
194{
195 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
196 int err, ch, changed = 0;
197
198 err = follower_init(follower);
199 if (err < 0)
200 return err;
201 for (ch = 0; ch < follower->info.count; ch++) {
202 if (ucontrol->value.integer.value[ch] < follower->info.min_val ||
203 ucontrol->value.integer.value[ch] > follower->info.max_val)
204 return -EINVAL;
205 }
206
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(&follower->list);
237 kfree(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_flex(*srec, follower.vd, follower->count);
260 if (!srec)
261 return -ENOMEM;
262 srec->kctl = follower;
263 srec->follower = *follower;
264 memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd));
265 srec->master = master_link;
266 srec->flags = flags;
267
268 /* override callbacks */
269 follower->info = follower_info;
270 follower->get = follower_get;
271 follower->put = follower_put;
272 if (follower->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
273 follower->tlv.c = follower_tlv_cmd;
274 follower->private_data = srec;
275 follower->private_free = follower_free;
276
277 list_add_tail(&srec->list, &master_link->followers);
278 return 0;
279}
280EXPORT_SYMBOL(_snd_ctl_add_follower);
281
282/**
283 * snd_ctl_add_followers - add multiple followers to vmaster
284 * @card: card instance
285 * @master: the target vmaster kcontrol object
286 * @list: NULL-terminated list of name strings of followers to be added
287 *
288 * Adds the multiple follower kcontrols with the given names.
289 * Returns 0 for success or a negative error code.
290 */
291int snd_ctl_add_followers(struct snd_card *card, struct snd_kcontrol *master,
292 const char * const *list)
293{
294 struct snd_kcontrol *follower;
295 int err;
296
297 for (; *list; list++) {
298 follower = snd_ctl_find_id_mixer(card, *list);
299 if (follower) {
300 err = snd_ctl_add_follower(master, follower);
301 if (err < 0)
302 return err;
303 }
304 }
305
306 return 0;
307}
308EXPORT_SYMBOL_GPL(snd_ctl_add_followers);
309
310/*
311 * ctl callbacks for master controls
312 */
313static int master_info(struct snd_kcontrol *kcontrol,
314 struct snd_ctl_elem_info *uinfo)
315{
316 struct link_master *master = snd_kcontrol_chip(kcontrol);
317 int ret;
318
319 ret = master_init(master);
320 if (ret < 0)
321 return ret;
322 uinfo->type = master->info.type;
323 uinfo->count = master->info.count;
324 uinfo->value.integer.min = master->info.min_val;
325 uinfo->value.integer.max = master->info.max_val;
326 return 0;
327}
328
329static int master_get(struct snd_kcontrol *kcontrol,
330 struct snd_ctl_elem_value *ucontrol)
331{
332 struct link_master *master = snd_kcontrol_chip(kcontrol);
333 int err = master_init(master);
334 if (err < 0)
335 return err;
336 ucontrol->value.integer.value[0] = master->val;
337 return 0;
338}
339
340static int sync_followers(struct link_master *master, int old_val, int new_val)
341{
342 struct link_follower *follower;
343 struct snd_ctl_elem_value *uval __free(kfree) =
344 kmalloc_obj(*uval);
345
346 if (!uval)
347 return -ENOMEM;
348 list_for_each_entry(follower, &master->followers, list) {
349 master->val = old_val;
350 uval->id = follower->follower.id;
351 follower_get_val(follower, uval);
352 master->val = new_val;
353 follower_put_val(follower, uval);
354 }
355 return 0;
356}
357
358static int master_put(struct snd_kcontrol *kcontrol,
359 struct snd_ctl_elem_value *ucontrol)
360{
361 struct link_master *master = snd_kcontrol_chip(kcontrol);
362 int err, new_val, old_val;
363 bool first_init;
364
365 err = master_init(master);
366 if (err < 0)
367 return err;
368 first_init = err;
369 old_val = master->val;
370 new_val = ucontrol->value.integer.value[0];
371 if (new_val == old_val)
372 return 0;
373 if (new_val < master->info.min_val || new_val > master->info.max_val)
374 return -EINVAL;
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(follower);
398 }
399 kfree(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_obj(*master);
433 if (!master)
434 return NULL;
435 INIT_LIST_HEAD(&master->followers);
436
437 kctl = snd_ctl_new1(&knew, master);
438 if (!kctl) {
439 kfree(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, master->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);