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 __free(kfree) = NULL;
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 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 struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
78 int err;
79
80 if (follower->info.count) {
81 /* already initialized */
82 if (follower->flags & SND_CTL_FOLLOWER_NEED_UPDATE)
83 return follower_update(follower);
84 return 0;
85 }
86
87 uinfo = kmalloc(size: sizeof(*uinfo), GFP_KERNEL);
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(master: 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 (follower->vals[ch] != ucontrol->value.integer.value[ch]) {
203 changed = 1;
204 follower->vals[ch] = ucontrol->value.integer.value[ch];
205 }
206 }
207 if (!changed)
208 return 0;
209 err = follower_put_val(follower, ucontrol);
210 if (err < 0)
211 return err;
212 return 1;
213}
214
215static int follower_tlv_cmd(struct snd_kcontrol *kcontrol,
216 int op_flag, unsigned int size,
217 unsigned int __user *tlv)
218{
219 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
220 /* FIXME: this assumes that the max volume is 0 dB */
221 return follower->follower.tlv.c(&follower->follower, op_flag, size, tlv);
222}
223
224static void follower_free(struct snd_kcontrol *kcontrol)
225{
226 struct link_follower *follower = snd_kcontrol_chip(kcontrol);
227 if (follower->follower.private_free)
228 follower->follower.private_free(&follower->follower);
229 if (follower->master)
230 list_del(entry: &follower->list);
231 kfree(objp: follower);
232}
233
234/*
235 * Add a follower control to the group with the given master control
236 *
237 * All followers must be the same type (returning the same information
238 * via info callback). The function doesn't check it, so it's your
239 * responsibility.
240 *
241 * Also, some additional limitations:
242 * - at most two channels
243 * - logarithmic volume control (dB level), no linear volume
244 * - master can only attenuate the volume, no gain
245 */
246int _snd_ctl_add_follower(struct snd_kcontrol *master,
247 struct snd_kcontrol *follower,
248 unsigned int flags)
249{
250 struct link_master *master_link = snd_kcontrol_chip(master);
251 struct link_follower *srec;
252
253 srec = kzalloc(struct_size(srec, follower.vd, follower->count),
254 GFP_KERNEL);
255 if (!srec)
256 return -ENOMEM;
257 srec->kctl = follower;
258 srec->follower = *follower;
259 memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd));
260 srec->master = master_link;
261 srec->flags = flags;
262
263 /* override callbacks */
264 follower->info = follower_info;
265 follower->get = follower_get;
266 follower->put = follower_put;
267 if (follower->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
268 follower->tlv.c = follower_tlv_cmd;
269 follower->private_data = srec;
270 follower->private_free = follower_free;
271
272 list_add_tail(new: &srec->list, head: &master_link->followers);
273 return 0;
274}
275EXPORT_SYMBOL(_snd_ctl_add_follower);
276
277/**
278 * snd_ctl_add_followers - add multiple followers to vmaster
279 * @card: card instance
280 * @master: the target vmaster kcontrol object
281 * @list: NULL-terminated list of name strings of followers to be added
282 *
283 * Adds the multiple follower kcontrols with the given names.
284 * Returns 0 for success or a negative error code.
285 */
286int snd_ctl_add_followers(struct snd_card *card, struct snd_kcontrol *master,
287 const char * const *list)
288{
289 struct snd_kcontrol *follower;
290 int err;
291
292 for (; *list; list++) {
293 follower = snd_ctl_find_id_mixer(card, name: *list);
294 if (follower) {
295 err = snd_ctl_add_follower(master, follower);
296 if (err < 0)
297 return err;
298 }
299 }
300
301 return 0;
302}
303EXPORT_SYMBOL_GPL(snd_ctl_add_followers);
304
305/*
306 * ctl callbacks for master controls
307 */
308static int master_info(struct snd_kcontrol *kcontrol,
309 struct snd_ctl_elem_info *uinfo)
310{
311 struct link_master *master = snd_kcontrol_chip(kcontrol);
312 int ret;
313
314 ret = master_init(master);
315 if (ret < 0)
316 return ret;
317 uinfo->type = master->info.type;
318 uinfo->count = master->info.count;
319 uinfo->value.integer.min = master->info.min_val;
320 uinfo->value.integer.max = master->info.max_val;
321 return 0;
322}
323
324static int master_get(struct snd_kcontrol *kcontrol,
325 struct snd_ctl_elem_value *ucontrol)
326{
327 struct link_master *master = snd_kcontrol_chip(kcontrol);
328 int err = master_init(master);
329 if (err < 0)
330 return err;
331 ucontrol->value.integer.value[0] = master->val;
332 return 0;
333}
334
335static int sync_followers(struct link_master *master, int old_val, int new_val)
336{
337 struct link_follower *follower;
338 struct snd_ctl_elem_value *uval __free(kfree) = NULL;
339
340 uval = kmalloc(size: sizeof(*uval), GFP_KERNEL);
341 if (!uval)
342 return -ENOMEM;
343 list_for_each_entry(follower, &master->followers, list) {
344 master->val = old_val;
345 uval->id = follower->follower.id;
346 follower_get_val(follower, ucontrol: uval);
347 master->val = new_val;
348 follower_put_val(follower, ucontrol: uval);
349 }
350 return 0;
351}
352
353static int master_put(struct snd_kcontrol *kcontrol,
354 struct snd_ctl_elem_value *ucontrol)
355{
356 struct link_master *master = snd_kcontrol_chip(kcontrol);
357 int err, new_val, old_val;
358 bool first_init;
359
360 err = master_init(master);
361 if (err < 0)
362 return err;
363 first_init = err;
364 old_val = master->val;
365 new_val = ucontrol->value.integer.value[0];
366 if (new_val == old_val)
367 return 0;
368
369 err = sync_followers(master, old_val, new_val);
370 if (err < 0)
371 return err;
372 if (master->hook && !first_init)
373 master->hook(master->hook_private_data, master->val);
374 return 1;
375}
376
377static void master_free(struct snd_kcontrol *kcontrol)
378{
379 struct link_master *master = snd_kcontrol_chip(kcontrol);
380 struct link_follower *follower, *n;
381
382 /* free all follower links and retore the original follower kctls */
383 list_for_each_entry_safe(follower, n, &master->followers, list) {
384 struct snd_kcontrol *sctl = follower->kctl;
385 struct list_head olist = sctl->list;
386 memcpy(sctl, &follower->follower, sizeof(*sctl));
387 memcpy(sctl->vd, follower->follower.vd,
388 sctl->count * sizeof(*sctl->vd));
389 sctl->list = olist; /* keep the current linked-list */
390 kfree(objp: follower);
391 }
392 kfree(objp: master);
393}
394
395
396/**
397 * snd_ctl_make_virtual_master - Create a virtual master control
398 * @name: name string of the control element to create
399 * @tlv: optional TLV int array for dB information
400 *
401 * Creates a virtual master control with the given name string.
402 *
403 * After creating a vmaster element, you can add the follower controls
404 * via snd_ctl_add_follower() or snd_ctl_add_follower_uncached().
405 *
406 * The optional argument @tlv can be used to specify the TLV information
407 * for dB scale of the master control. It should be a single element
408 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
409 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
410 *
411 * Return: The created control element, or %NULL for errors (ENOMEM).
412 */
413struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
414 const unsigned int *tlv)
415{
416 struct link_master *master;
417 struct snd_kcontrol *kctl;
418 struct snd_kcontrol_new knew;
419
420 memset(&knew, 0, sizeof(knew));
421 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
422 knew.name = name;
423 knew.info = master_info;
424
425 master = kzalloc(size: sizeof(*master), GFP_KERNEL);
426 if (!master)
427 return NULL;
428 INIT_LIST_HEAD(list: &master->followers);
429
430 kctl = snd_ctl_new1(kcontrolnew: &knew, private_data: master);
431 if (!kctl) {
432 kfree(objp: master);
433 return NULL;
434 }
435 /* override some callbacks */
436 kctl->info = master_info;
437 kctl->get = master_get;
438 kctl->put = master_put;
439 kctl->private_free = master_free;
440
441 /* additional (constant) TLV read */
442 if (tlv) {
443 unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
444 if (type == SNDRV_CTL_TLVT_DB_SCALE ||
445 type == SNDRV_CTL_TLVT_DB_MINMAX ||
446 type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
447 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
448 memcpy(master->tlv, tlv, sizeof(master->tlv));
449 kctl->tlv.p = master->tlv;
450 }
451 }
452
453 return kctl;
454}
455EXPORT_SYMBOL(snd_ctl_make_virtual_master);
456
457/**
458 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
459 * @kcontrol: vmaster kctl element
460 * @hook: the hook function
461 * @private_data: the private_data pointer to be saved
462 *
463 * Adds the given hook to the vmaster control element so that it's called
464 * at each time when the value is changed.
465 *
466 * Return: Zero.
467 */
468int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
469 void (*hook)(void *private_data, int),
470 void *private_data)
471{
472 struct link_master *master = snd_kcontrol_chip(kcontrol);
473 master->hook = hook;
474 master->hook_private_data = private_data;
475 return 0;
476}
477EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
478
479/**
480 * snd_ctl_sync_vmaster - Sync the vmaster followers and hook
481 * @kcontrol: vmaster kctl element
482 * @hook_only: sync only the hook
483 *
484 * Forcibly call the put callback of each follower and call the hook function
485 * to synchronize with the current value of the given vmaster element.
486 * NOP when NULL is passed to @kcontrol.
487 */
488void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
489{
490 struct link_master *master;
491 bool first_init = false;
492
493 if (!kcontrol)
494 return;
495 master = snd_kcontrol_chip(kcontrol);
496 if (!hook_only) {
497 int err = master_init(master);
498 if (err < 0)
499 return;
500 first_init = err;
501 err = sync_followers(master, old_val: master->val, new_val: master->val);
502 if (err < 0)
503 return;
504 }
505
506 if (master->hook && !first_init)
507 master->hook(master->hook_private_data, master->val);
508}
509EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
510
511/**
512 * snd_ctl_apply_vmaster_followers - Apply function to each vmaster follower
513 * @kctl: vmaster kctl element
514 * @func: function to apply
515 * @arg: optional function argument
516 *
517 * Apply the function @func to each follower kctl of the given vmaster kctl.
518 *
519 * Return: 0 if successful, or a negative error code
520 */
521int snd_ctl_apply_vmaster_followers(struct snd_kcontrol *kctl,
522 int (*func)(struct snd_kcontrol *vfollower,
523 struct snd_kcontrol *follower,
524 void *arg),
525 void *arg)
526{
527 struct link_master *master;
528 struct link_follower *follower;
529 int err;
530
531 master = snd_kcontrol_chip(kctl);
532 err = master_init(master);
533 if (err < 0)
534 return err;
535 list_for_each_entry(follower, &master->followers, list) {
536 err = func(follower->kctl, &follower->follower, arg);
537 if (err < 0)
538 return err;
539 }
540
541 return 0;
542}
543EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);
544

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