sound/core/vmaster.c

   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
  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 */
  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 */
 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
 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
 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  */
 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
 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
 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
 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
 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  */
 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  * ctl callbacks for master controls
 285  */
 286 static 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
 302 static 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
 313 static 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
 332 static 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
 356 static 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  */
 392 struct 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 }
 434 EXPORT_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  */
 447 int 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 }
 456 EXPORT_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  */
 467 void 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 }
 488 EXPORT_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  */
 499 int 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 }
 521 EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);