xref: /openbmc/linux/sound/core/vmaster.c (revision ae07eb9b)
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  */
17 struct 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  */
31 struct 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 
47 struct 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 
follower_update(struct link_follower * follower)57 static 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 */
follower_init(struct link_follower * follower)77 static 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 */
master_init(struct link_master * master)115 static 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 
follower_get_val(struct link_follower * follower,struct snd_ctl_elem_value * ucontrol)137 static 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 
follower_put_val(struct link_follower * follower,struct snd_ctl_elem_value * ucontrol)150 static 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  */
follower_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)184 static 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 
follower_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)191 static 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 
follower_put(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)198 static 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 
follower_tlv_cmd(struct snd_kcontrol * kcontrol,int op_flag,unsigned int size,unsigned int __user * tlv)221 static 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 
follower_free(struct snd_kcontrol * kcontrol)230 static 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  */
_snd_ctl_add_follower(struct snd_kcontrol * master,struct snd_kcontrol * follower,unsigned int flags)252 int _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 }
281 EXPORT_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  */
snd_ctl_add_followers(struct snd_card * card,struct snd_kcontrol * master,const char * const * list)292 int 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, *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 }
309 EXPORT_SYMBOL_GPL(snd_ctl_add_followers);
310 
311 /*
312  * ctl callbacks for master controls
313  */
master_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)314 static 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 
master_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)330 static 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 
sync_followers(struct link_master * master,int old_val,int new_val)341 static 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(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, uval);
353 		master->val = new_val;
354 		follower_put_val(follower, uval);
355 	}
356 	kfree(uval);
357 	return 0;
358 }
359 
master_put(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)360 static 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 
master_free(struct snd_kcontrol * kcontrol)384 static 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  */
snd_ctl_make_virtual_master(char * name,const unsigned int * tlv)420 struct 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(sizeof(*master), GFP_KERNEL);
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 }
462 EXPORT_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  */
snd_ctl_add_vmaster_hook(struct snd_kcontrol * kcontrol,void (* hook)(void * private_data,int),void * private_data)475 int 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 }
484 EXPORT_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  */
snd_ctl_sync_vmaster(struct snd_kcontrol * kcontrol,bool hook_only)495 void 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 }
516 EXPORT_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  */
snd_ctl_apply_vmaster_followers(struct snd_kcontrol * kctl,int (* func)(struct snd_kcontrol * vfollower,struct snd_kcontrol * follower,void * arg),void * arg)528 int 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 }
550 EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);
551