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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Virtual master and slave 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 slave 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 slaves.
30 */
31struct link_master {
32 struct list_head slaves;
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 slave - this contains a slave control element
42 *
43 * It fakes the control callbacsk with additional attenuation by the
44 * master control. A slave may have either one or two channels.
45 */
46
47struct link_slave {
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 slave; /* the copy of original control entry */
55};
56
57static int slave_update(struct link_slave *slave)
58{
59 struct snd_ctl_elem_value *uctl;
60 int err, ch;
61
62 uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
63 if (!uctl)
64 return -ENOMEM;
65 uctl->id = slave->slave.id;
66 err = slave->slave.get(&slave->slave, uctl);
67 if (err < 0)
68 goto error;
69 for (ch = 0; ch < slave->info.count; ch++)
70 slave->vals[ch] = uctl->value.integer.value[ch];
71 error:
72 kfree(uctl);
73 return err < 0 ? err : 0;
74}
75
76/* get the slave ctl info and save the initial values */
77static int slave_init(struct link_slave *slave)
78{
79 struct snd_ctl_elem_info *uinfo;
80 int err;
81
82 if (slave->info.count) {
83 /* already initialized */
84 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
85 return slave_update(slave);
86 return 0;
87 }
88
89 uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
90 if (!uinfo)
91 return -ENOMEM;
92 uinfo->id = slave->slave.id;
93 err = slave->slave.info(&slave->slave, uinfo);
94 if (err < 0) {
95 kfree(uinfo);
96 return err;
97 }
98 slave->info.type = uinfo->type;
99 slave->info.count = uinfo->count;
100 if (slave->info.count > 2 ||
101 (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
102 slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
103 pr_err("ALSA: vmaster: invalid slave element\n");
104 kfree(uinfo);
105 return -EINVAL;
106 }
107 slave->info.min_val = uinfo->value.integer.min;
108 slave->info.max_val = uinfo->value.integer.max;
109 kfree(uinfo);
110
111 return slave_update(slave);
112}
113
114/* initialize master volume */
115static int master_init(struct link_master *master)
116{
117 struct link_slave *slave;
118
119 if (master->info.count)
120 return 0; /* already initialized */
121
122 list_for_each_entry(slave, &master->slaves, list) {
123 int err = slave_init(slave);
124 if (err < 0)
125 return err;
126 master->info = slave->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 slave_get_val(struct link_slave *slave,
138 struct snd_ctl_elem_value *ucontrol)
139{
140 int err, ch;
141
142 err = slave_init(slave);
143 if (err < 0)
144 return err;
145 for (ch = 0; ch < slave->info.count; ch++)
146 ucontrol->value.integer.value[ch] = slave->vals[ch];
147 return 0;
148}
149
150static int slave_put_val(struct link_slave *slave,
151 struct snd_ctl_elem_value *ucontrol)
152{
153 int err, ch, vol;
154
155 err = master_init(slave->master);
156 if (err < 0)
157 return err;
158
159 switch (slave->info.type) {
160 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
161 for (ch = 0; ch < slave->info.count; ch++)
162 ucontrol->value.integer.value[ch] &=
163 !!slave->master->val;
164 break;
165 case SNDRV_CTL_ELEM_TYPE_INTEGER:
166 for (ch = 0; ch < slave->info.count; ch++) {
167 /* max master volume is supposed to be 0 dB */
168 vol = ucontrol->value.integer.value[ch];
169 vol += slave->master->val - slave->master->info.max_val;
170 if (vol < slave->info.min_val)
171 vol = slave->info.min_val;
172 else if (vol > slave->info.max_val)
173 vol = slave->info.max_val;
174 ucontrol->value.integer.value[ch] = vol;
175 }
176 break;
177 }
178 return slave->slave.put(&slave->slave, ucontrol);
179}
180
181/*
182 * ctl callbacks for slaves
183 */
184static int slave_info(struct snd_kcontrol *kcontrol,
185 struct snd_ctl_elem_info *uinfo)
186{
187 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
188 return slave->slave.info(&slave->slave, uinfo);
189}
190
191static int slave_get(struct snd_kcontrol *kcontrol,
192 struct snd_ctl_elem_value *ucontrol)
193{
194 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
195 return slave_get_val(slave, ucontrol);
196}
197
198static int slave_put(struct snd_kcontrol *kcontrol,
199 struct snd_ctl_elem_value *ucontrol)
200{
201 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
202 int err, ch, changed = 0;
203
204 err = slave_init(slave);
205 if (err < 0)
206 return err;
207 for (ch = 0; ch < slave->info.count; ch++) {
208 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
209 changed = 1;
210 slave->vals[ch] = ucontrol->value.integer.value[ch];
211 }
212 }
213 if (!changed)
214 return 0;
215 err = slave_put_val(slave, ucontrol);
216 if (err < 0)
217 return err;
218 return 1;
219}
220
221static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
222 int op_flag, unsigned int size,
223 unsigned int __user *tlv)
224{
225 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
226 /* FIXME: this assumes that the max volume is 0 dB */
227 return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
228}
229
230static void slave_free(struct snd_kcontrol *kcontrol)
231{
232 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
233 if (slave->slave.private_free)
234 slave->slave.private_free(&slave->slave);
235 if (slave->master)
236 list_del(&slave->list);
237 kfree(slave);
238}
239
240/*
241 * Add a slave control to the group with the given master control
242 *
243 * All slaves 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_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
253 unsigned int flags)
254{
255 struct link_master *master_link = snd_kcontrol_chip(master);
256 struct link_slave *srec;
257
258 srec = kzalloc(struct_size(srec, slave.vd, slave->count),
259 GFP_KERNEL);
260 if (!srec)
261 return -ENOMEM;
262 srec->kctl = slave;
263 srec->slave = *slave;
264 memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
265 srec->master = master_link;
266 srec->flags = flags;
267
268 /* override callbacks */
269 slave->info = slave_info;
270 slave->get = slave_get;
271 slave->put = slave_put;
272 if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
273 slave->tlv.c = slave_tlv_cmd;
274 slave->private_data = srec;
275 slave->private_free = slave_free;
276
277 list_add_tail(&srec->list, &master_link->slaves);
278 return 0;
279}
280EXPORT_SYMBOL(_snd_ctl_add_slave);
281
282/*
283 * ctl callbacks for master controls
284 */
285static int master_info(struct snd_kcontrol *kcontrol,
286 struct snd_ctl_elem_info *uinfo)
287{
288 struct link_master *master = snd_kcontrol_chip(kcontrol);
289 int ret;
290
291 ret = master_init(master);
292 if (ret < 0)
293 return ret;
294 uinfo->type = master->info.type;
295 uinfo->count = master->info.count;
296 uinfo->value.integer.min = master->info.min_val;
297 uinfo->value.integer.max = master->info.max_val;
298 return 0;
299}
300
301static int master_get(struct snd_kcontrol *kcontrol,
302 struct snd_ctl_elem_value *ucontrol)
303{
304 struct link_master *master = snd_kcontrol_chip(kcontrol);
305 int err = master_init(master);
306 if (err < 0)
307 return err;
308 ucontrol->value.integer.value[0] = master->val;
309 return 0;
310}
311
312static int sync_slaves(struct link_master *master, int old_val, int new_val)
313{
314 struct link_slave *slave;
315 struct snd_ctl_elem_value *uval;
316
317 uval = kmalloc(sizeof(*uval), GFP_KERNEL);
318 if (!uval)
319 return -ENOMEM;
320 list_for_each_entry(slave, &master->slaves, list) {
321 master->val = old_val;
322 uval->id = slave->slave.id;
323 slave_get_val(slave, uval);
324 master->val = new_val;
325 slave_put_val(slave, uval);
326 }
327 kfree(uval);
328 return 0;
329}
330
331static int master_put(struct snd_kcontrol *kcontrol,
332 struct snd_ctl_elem_value *ucontrol)
333{
334 struct link_master *master = snd_kcontrol_chip(kcontrol);
335 int err, new_val, old_val;
336 bool first_init;
337
338 err = master_init(master);
339 if (err < 0)
340 return err;
341 first_init = err;
342 old_val = master->val;
343 new_val = ucontrol->value.integer.value[0];
344 if (new_val == old_val)
345 return 0;
346
347 err = sync_slaves(master, old_val, new_val);
348 if (err < 0)
349 return err;
350 if (master->hook && !first_init)
351 master->hook(master->hook_private_data, master->val);
352 return 1;
353}
354
355static void master_free(struct snd_kcontrol *kcontrol)
356{
357 struct link_master *master = snd_kcontrol_chip(kcontrol);
358 struct link_slave *slave, *n;
359
360 /* free all slave links and retore the original slave kctls */
361 list_for_each_entry_safe(slave, n, &master->slaves, list) {
362 struct snd_kcontrol *sctl = slave->kctl;
363 struct list_head olist = sctl->list;
364 memcpy(sctl, &slave->slave, sizeof(*sctl));
365 memcpy(sctl->vd, slave->slave.vd,
366 sctl->count * sizeof(*sctl->vd));
367 sctl->list = olist; /* keep the current linked-list */
368 kfree(slave);
369 }
370 kfree(master);
371}
372
373
374/**
375 * snd_ctl_make_virtual_master - Create a virtual master control
376 * @name: name string of the control element to create
377 * @tlv: optional TLV int array for dB information
378 *
379 * Creates a virtual master control with the given name string.
380 *
381 * After creating a vmaster element, you can add the slave controls
382 * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
383 *
384 * The optional argument @tlv can be used to specify the TLV information
385 * for dB scale of the master control. It should be a single element
386 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
387 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
388 *
389 * Return: The created control element, or %NULL for errors (ENOMEM).
390 */
391struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
392 const unsigned int *tlv)
393{
394 struct link_master *master;
395 struct snd_kcontrol *kctl;
396 struct snd_kcontrol_new knew;
397
398 memset(&knew, 0, sizeof(knew));
399 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
400 knew.name = name;
401 knew.info = master_info;
402
403 master = kzalloc(sizeof(*master), GFP_KERNEL);
404 if (!master)
405 return NULL;
406 INIT_LIST_HEAD(&master->slaves);
407
408 kctl = snd_ctl_new1(&knew, master);
409 if (!kctl) {
410 kfree(master);
411 return NULL;
412 }
413 /* override some callbacks */
414 kctl->info = master_info;
415 kctl->get = master_get;
416 kctl->put = master_put;
417 kctl->private_free = master_free;
418
419 /* additional (constant) TLV read */
420 if (tlv) {
421 unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
422 if (type == SNDRV_CTL_TLVT_DB_SCALE ||
423 type == SNDRV_CTL_TLVT_DB_MINMAX ||
424 type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
425 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
426 memcpy(master->tlv, tlv, sizeof(master->tlv));
427 kctl->tlv.p = master->tlv;
428 }
429 }
430
431 return kctl;
432}
433EXPORT_SYMBOL(snd_ctl_make_virtual_master);
434
435/**
436 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
437 * @kcontrol: vmaster kctl element
438 * @hook: the hook function
439 * @private_data: the private_data pointer to be saved
440 *
441 * Adds the given hook to the vmaster control element so that it's called
442 * at each time when the value is changed.
443 *
444 * Return: Zero.
445 */
446int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
447 void (*hook)(void *private_data, int),
448 void *private_data)
449{
450 struct link_master *master = snd_kcontrol_chip(kcontrol);
451 master->hook = hook;
452 master->hook_private_data = private_data;
453 return 0;
454}
455EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
456
457/**
458 * snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
459 * @kcontrol: vmaster kctl element
460 * @hook_only: sync only the hook
461 *
462 * Forcibly call the put callback of each slave and call the hook function
463 * to synchronize with the current value of the given vmaster element.
464 * NOP when NULL is passed to @kcontrol.
465 */
466void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
467{
468 struct link_master *master;
469 bool first_init = false;
470
471 if (!kcontrol)
472 return;
473 master = snd_kcontrol_chip(kcontrol);
474 if (!hook_only) {
475 int err = master_init(master);
476 if (err < 0)
477 return;
478 first_init = err;
479 err = sync_slaves(master, master->val, master->val);
480 if (err < 0)
481 return;
482 }
483
484 if (master->hook && !first_init)
485 master->hook(master->hook_private_data, master->val);
486}
487EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
488
489/**
490 * snd_ctl_apply_vmaster_slaves - Apply function to each vmaster slave
491 * @kctl: vmaster kctl element
492 * @func: function to apply
493 * @arg: optional function argument
494 *
495 * Apply the function @func to each slave kctl of the given vmaster kctl.
496 * Returns 0 if successful, or a negative error code.
497 */
498int snd_ctl_apply_vmaster_slaves(struct snd_kcontrol *kctl,
499 int (*func)(struct snd_kcontrol *vslave,
500 struct snd_kcontrol *slave,
501 void *arg),
502 void *arg)
503{
504 struct link_master *master;
505 struct link_slave *slave;
506 int err;
507
508 master = snd_kcontrol_chip(kctl);
509 err = master_init(master);
510 if (err < 0)
511 return err;
512 list_for_each_entry(slave, &master->slaves, list) {
513 err = func(slave->kctl, &slave->slave, arg);
514 if (err < 0)
515 return err;
516 }
517
518 return 0;
519}
520EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_slaves);
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(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(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(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(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(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(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(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(&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(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(&srec->list, &master_link->followers);
279 return 0;
280}
281EXPORT_SYMBOL(_snd_ctl_add_follower);
282
283/*
284 * ctl callbacks for master controls
285 */
286static int master_info(struct snd_kcontrol *kcontrol,
287 struct snd_ctl_elem_info *uinfo)
288{
289 struct link_master *master = snd_kcontrol_chip(kcontrol);
290 int ret;
291
292 ret = master_init(master);
293 if (ret < 0)
294 return ret;
295 uinfo->type = master->info.type;
296 uinfo->count = master->info.count;
297 uinfo->value.integer.min = master->info.min_val;
298 uinfo->value.integer.max = master->info.max_val;
299 return 0;
300}
301
302static int master_get(struct snd_kcontrol *kcontrol,
303 struct snd_ctl_elem_value *ucontrol)
304{
305 struct link_master *master = snd_kcontrol_chip(kcontrol);
306 int err = master_init(master);
307 if (err < 0)
308 return err;
309 ucontrol->value.integer.value[0] = master->val;
310 return 0;
311}
312
313static int sync_followers(struct link_master *master, int old_val, int new_val)
314{
315 struct link_follower *follower;
316 struct snd_ctl_elem_value *uval;
317
318 uval = kmalloc(sizeof(*uval), GFP_KERNEL);
319 if (!uval)
320 return -ENOMEM;
321 list_for_each_entry(follower, &master->followers, list) {
322 master->val = old_val;
323 uval->id = follower->follower.id;
324 follower_get_val(follower, uval);
325 master->val = new_val;
326 follower_put_val(follower, uval);
327 }
328 kfree(uval);
329 return 0;
330}
331
332static int master_put(struct snd_kcontrol *kcontrol,
333 struct snd_ctl_elem_value *ucontrol)
334{
335 struct link_master *master = snd_kcontrol_chip(kcontrol);
336 int err, new_val, old_val;
337 bool first_init;
338
339 err = master_init(master);
340 if (err < 0)
341 return err;
342 first_init = err;
343 old_val = master->val;
344 new_val = ucontrol->value.integer.value[0];
345 if (new_val == old_val)
346 return 0;
347
348 err = sync_followers(master, old_val, new_val);
349 if (err < 0)
350 return err;
351 if (master->hook && !first_init)
352 master->hook(master->hook_private_data, master->val);
353 return 1;
354}
355
356static void master_free(struct snd_kcontrol *kcontrol)
357{
358 struct link_master *master = snd_kcontrol_chip(kcontrol);
359 struct link_follower *follower, *n;
360
361 /* free all follower links and retore the original follower kctls */
362 list_for_each_entry_safe(follower, n, &master->followers, list) {
363 struct snd_kcontrol *sctl = follower->kctl;
364 struct list_head olist = sctl->list;
365 memcpy(sctl, &follower->follower, sizeof(*sctl));
366 memcpy(sctl->vd, follower->follower.vd,
367 sctl->count * sizeof(*sctl->vd));
368 sctl->list = olist; /* keep the current linked-list */
369 kfree(follower);
370 }
371 kfree(master);
372}
373
374
375/**
376 * snd_ctl_make_virtual_master - Create a virtual master control
377 * @name: name string of the control element to create
378 * @tlv: optional TLV int array for dB information
379 *
380 * Creates a virtual master control with the given name string.
381 *
382 * After creating a vmaster element, you can add the follower controls
383 * via snd_ctl_add_follower() or snd_ctl_add_follower_uncached().
384 *
385 * The optional argument @tlv can be used to specify the TLV information
386 * for dB scale of the master control. It should be a single element
387 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
388 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
389 *
390 * Return: The created control element, or %NULL for errors (ENOMEM).
391 */
392struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
393 const unsigned int *tlv)
394{
395 struct link_master *master;
396 struct snd_kcontrol *kctl;
397 struct snd_kcontrol_new knew;
398
399 memset(&knew, 0, sizeof(knew));
400 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
401 knew.name = name;
402 knew.info = master_info;
403
404 master = kzalloc(sizeof(*master), GFP_KERNEL);
405 if (!master)
406 return NULL;
407 INIT_LIST_HEAD(&master->followers);
408
409 kctl = snd_ctl_new1(&knew, master);
410 if (!kctl) {
411 kfree(master);
412 return NULL;
413 }
414 /* override some callbacks */
415 kctl->info = master_info;
416 kctl->get = master_get;
417 kctl->put = master_put;
418 kctl->private_free = master_free;
419
420 /* additional (constant) TLV read */
421 if (tlv) {
422 unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
423 if (type == SNDRV_CTL_TLVT_DB_SCALE ||
424 type == SNDRV_CTL_TLVT_DB_MINMAX ||
425 type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
426 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
427 memcpy(master->tlv, tlv, sizeof(master->tlv));
428 kctl->tlv.p = master->tlv;
429 }
430 }
431
432 return kctl;
433}
434EXPORT_SYMBOL(snd_ctl_make_virtual_master);
435
436/**
437 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
438 * @kcontrol: vmaster kctl element
439 * @hook: the hook function
440 * @private_data: the private_data pointer to be saved
441 *
442 * Adds the given hook to the vmaster control element so that it's called
443 * at each time when the value is changed.
444 *
445 * Return: Zero.
446 */
447int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
448 void (*hook)(void *private_data, int),
449 void *private_data)
450{
451 struct link_master *master = snd_kcontrol_chip(kcontrol);
452 master->hook = hook;
453 master->hook_private_data = private_data;
454 return 0;
455}
456EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
457
458/**
459 * snd_ctl_sync_vmaster - Sync the vmaster followers and hook
460 * @kcontrol: vmaster kctl element
461 * @hook_only: sync only the hook
462 *
463 * Forcibly call the put callback of each follower and call the hook function
464 * to synchronize with the current value of the given vmaster element.
465 * NOP when NULL is passed to @kcontrol.
466 */
467void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
468{
469 struct link_master *master;
470 bool first_init = false;
471
472 if (!kcontrol)
473 return;
474 master = snd_kcontrol_chip(kcontrol);
475 if (!hook_only) {
476 int err = master_init(master);
477 if (err < 0)
478 return;
479 first_init = err;
480 err = sync_followers(master, master->val, master->val);
481 if (err < 0)
482 return;
483 }
484
485 if (master->hook && !first_init)
486 master->hook(master->hook_private_data, master->val);
487}
488EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
489
490/**
491 * snd_ctl_apply_vmaster_followers - Apply function to each vmaster follower
492 * @kctl: vmaster kctl element
493 * @func: function to apply
494 * @arg: optional function argument
495 *
496 * Apply the function @func to each follower kctl of the given vmaster kctl.
497 * Returns 0 if successful, or a negative error code.
498 */
499int snd_ctl_apply_vmaster_followers(struct snd_kcontrol *kctl,
500 int (*func)(struct snd_kcontrol *vfollower,
501 struct snd_kcontrol *follower,
502 void *arg),
503 void *arg)
504{
505 struct link_master *master;
506 struct link_follower *follower;
507 int err;
508
509 master = snd_kcontrol_chip(kctl);
510 err = master_init(master);
511 if (err < 0)
512 return err;
513 list_for_each_entry(follower, &master->followers, list) {
514 err = func(follower->kctl, &follower->follower, arg);
515 if (err < 0)
516 return err;
517 }
518
519 return 0;
520}
521EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);