root/sound/core/vmaster.c

DEFINITIONS

1. slave_update
2. slave_init
3. master_init
4. slave_get_val
5. slave_put_val
6. slave_info
7. slave_get
8. slave_put
9. slave_tlv_cmd
10. slave_free
11. _snd_ctl_add_slave
12. master_info
13. master_get
14. sync_slaves
15. master_put
16. master_free
17. snd_ctl_make_virtual_master
18. snd_ctl_add_vmaster_hook
19. snd_ctl_sync_vmaster
20. snd_ctl_apply_vmaster_slaves

   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  */
  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 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  */
  31 struct 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 
  47 struct 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 
  57 static 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 */
  77 static 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 */
 115 static 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 
 137 static 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 
 150 static 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  */
 184 static 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 
 191 static 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 
 198 static 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 
 221 static 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 
 230 static 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  */
 252 int _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 }
 280 EXPORT_SYMBOL(_snd_ctl_add_slave);
 281 
 282 /*
 283  * ctl callbacks for master controls
 284  */
 285 static 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 
 301 static 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 
 312 static 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 
 331 static 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 
 355 static 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  */
 391 struct 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 }
 433 EXPORT_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  */
 446 int 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 }
 455 EXPORT_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  */
 466 void 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 }
 487 EXPORT_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  */
 498 int 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 }
 520 EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_slaves);