sound/core/vmaster.c

   1 /*
   2  * Virtual master and slave controls
   3  *
   4  *  Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License as
   8  *  published by the Free Software Foundation, version 2.
   9  *
  10  */
  11
  12 #include <linux/slab.h>
  13 #include <linux/export.h>
  14 #include <sound/core.h>
  15 #include <sound/control.h>
  16 #include <sound/tlv.h>
  17
  18 /*
  19  * a subset of information returned via ctl info callback
  20  */
  21 struct link_ctl_info {
  22         snd_ctl_elem_type_t type; /* value type */
  23         int count;              /* item count */
  24         int min_val, max_val;   /* min, max values */
  25 };
  26
  27 /*
  28  * link master - this contains a list of slave controls that are
  29  * identical types, i.e. info returns the same value type and value
  30  * ranges, but may have different number of counts.
  31  *
  32  * The master control is so far only mono volume/switch for simplicity.
  33  * The same value will be applied to all slaves.
  34  */
  35 struct link_master {
  36         struct list_head slaves;
  37         struct link_ctl_info info;
  38         int val;                /* the master value */
  39         unsigned int tlv[4];
  40 };
  41
  42 /*
  43  * link slave - this contains a slave control element
  44  *
  45  * It fakes the control callbacsk with additional attenuation by the
  46  * master control.  A slave may have either one or two channels.
  47  */
  48
  49 struct link_slave {
  50         struct list_head list;
  51         struct link_master *master;
  52         struct link_ctl_info info;
  53         int vals[2];            /* current values */
  54         unsigned int flags;
  55         struct snd_kcontrol *kctl; /* original kcontrol pointer */
  56         struct snd_kcontrol slave; /* the copy of original control entry */
  57 };
  58
  59 static int slave_update(struct link_slave *slave)
  60 {
  61         struct snd_ctl_elem_value *uctl;
  62         int err, ch;
  63
  64         uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
  65         if (!uctl)
  66                 return -ENOMEM;
  67         uctl->id = slave->slave.id;
  68         err = slave->slave.get(&slave->slave, uctl);
  69         for (ch = 0; ch < slave->info.count; ch++)
  70                 slave->vals[ch] = uctl->value.integer.value[ch];
  71         kfree(uctl);
  72         return 0;
  73 }
  74
  75 /* get the slave ctl info and save the initial values */
  76 static int slave_init(struct link_slave *slave)
  77 {
  78         struct snd_ctl_elem_info *uinfo;
  79         int err;
  80
  81         if (slave->info.count) {
  82                 /* already initialized */
  83                 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
  84                         return slave_update(slave);
  85                 return 0;
  86         }
  87
  88         uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
  89         if (!uinfo)
  90                 return -ENOMEM;
  91         uinfo->id = slave->slave.id;
  92         err = slave->slave.info(&slave->slave, uinfo);
  93         if (err < 0) {
  94                 kfree(uinfo);
  95                 return err;
  96         }
  97         slave->info.type = uinfo->type;
  98         slave->info.count = uinfo->count;
  99         if (slave->info.count > 2  ||
 100             (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
 101              slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
 102                 snd_printk(KERN_ERR "invalid slave element\n");
 103                 kfree(uinfo);
 104                 return -EINVAL;
 105         }
 106         slave->info.min_val = uinfo->value.integer.min;
 107         slave->info.max_val = uinfo->value.integer.max;
 108         kfree(uinfo);
 109
 110         return slave_update(slave);
 111 }
 112
 113 /* initialize master volume */
 114 static int master_init(struct link_master *master)
 115 {
 116         struct link_slave *slave;
 117
 118         if (master->info.count)
 119                 return 0; /* already initialized */
 120
 121         list_for_each_entry(slave, &master->slaves, list) {
 122                 int err = slave_init(slave);
 123                 if (err < 0)
 124                         return err;
 125                 master->info = slave->info;
 126                 master->info.count = 1; /* always mono */
 127                 /* set full volume as default (= no attenuation) */
 128                 master->val = master->info.max_val;
 129                 return 0;
 130         }
 131         return -ENOENT;
 132 }
 133
 134 static int slave_get_val(struct link_slave *slave,
 135                          struct snd_ctl_elem_value *ucontrol)
 136 {
 137         int err, ch;
 138
 139         err = slave_init(slave);
 140         if (err < 0)
 141                 return err;
 142         for (ch = 0; ch < slave->info.count; ch++)
 143                 ucontrol->value.integer.value[ch] = slave->vals[ch];
 144         return 0;
 145 }
 146
 147 static int slave_put_val(struct link_slave *slave,
 148                          struct snd_ctl_elem_value *ucontrol)
 149 {
 150         int err, ch, vol;
 151
 152         err = master_init(slave->master);
 153         if (err < 0)
 154                 return err;
 155
 156         switch (slave->info.type) {
 157         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 158                 for (ch = 0; ch < slave->info.count; ch++)
 159                         ucontrol->value.integer.value[ch] &=
 160                                 !!slave->master->val;
 161                 break;
 162         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 163                 for (ch = 0; ch < slave->info.count; ch++) {
 164                         /* max master volume is supposed to be 0 dB */
 165                         vol = ucontrol->value.integer.value[ch];
 166                         vol += slave->master->val - slave->master->info.max_val;
 167                         if (vol < slave->info.min_val)
 168                                 vol = slave->info.min_val;
 169                         else if (vol > slave->info.max_val)
 170                                 vol = slave->info.max_val;
 171                         ucontrol->value.integer.value[ch] = vol;
 172                 }
 173                 break;
 174         }
 175         return slave->slave.put(&slave->slave, ucontrol);
 176 }
 177
 178 /*
 179  * ctl callbacks for slaves
 180  */
 181 static int slave_info(struct snd_kcontrol *kcontrol,
 182                       struct snd_ctl_elem_info *uinfo)
 183 {
 184         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 185         return slave->slave.info(&slave->slave, uinfo);
 186 }
 187
 188 static int slave_get(struct snd_kcontrol *kcontrol,
 189                      struct snd_ctl_elem_value *ucontrol)
 190 {
 191         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 192         return slave_get_val(slave, ucontrol);
 193 }
 194
 195 static int slave_put(struct snd_kcontrol *kcontrol,
 196                      struct snd_ctl_elem_value *ucontrol)
 197 {
 198         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 199         int err, ch, changed = 0;
 200
 201         err = slave_init(slave);
 202         if (err < 0)
 203                 return err;
 204         for (ch = 0; ch < slave->info.count; ch++) {
 205                 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
 206                         changed = 1;
 207                         slave->vals[ch] = ucontrol->value.integer.value[ch];
 208                 }
 209         }
 210         if (!changed)
 211                 return 0;
 212         return slave_put_val(slave, ucontrol);
 213 }
 214
 215 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
 216                          int op_flag, unsigned int size,
 217                          unsigned int __user *tlv)
 218 {
 219         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 220         /* FIXME: this assumes that the max volume is 0 dB */
 221         return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
 222 }
 223
 224 static void slave_free(struct snd_kcontrol *kcontrol)
 225 {
 226         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 227         if (slave->slave.private_free)
 228                 slave->slave.private_free(&slave->slave);
 229         if (slave->master)
 230                 list_del(&slave->list);
 231         kfree(slave);
 232 }
 233
 234 /*
 235  * Add a slave control to the group with the given master control
 236  *
 237  * All slaves 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  */
 246 int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
 247                        unsigned int flags)
 248 {
 249         struct link_master *master_link = snd_kcontrol_chip(master);
 250         struct link_slave *srec;
 251
 252         srec = kzalloc(sizeof(*srec) +
 253                        slave->count * sizeof(*slave->vd), GFP_KERNEL);
 254         if (!srec)
 255                 return -ENOMEM;
 256         srec->kctl = slave;
 257         srec->slave = *slave;
 258         memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
 259         srec->master = master_link;
 260         srec->flags = flags;
 261
 262         /* override callbacks */
 263         slave->info = slave_info;
 264         slave->get = slave_get;
 265         slave->put = slave_put;
 266         if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
 267                 slave->tlv.c = slave_tlv_cmd;
 268         slave->private_data = srec;
 269         slave->private_free = slave_free;
 270
 271         list_add_tail(&srec->list, &master_link->slaves);
 272         return 0;
 273 }
 274 EXPORT_SYMBOL(_snd_ctl_add_slave);
 275
 276 /*
 277  * ctl callbacks for master controls
 278  */
 279 static int master_info(struct snd_kcontrol *kcontrol,
 280                       struct snd_ctl_elem_info *uinfo)
 281 {
 282         struct link_master *master = snd_kcontrol_chip(kcontrol);
 283         int ret;
 284
 285         ret = master_init(master);
 286         if (ret < 0)
 287                 return ret;
 288         uinfo->type = master->info.type;
 289         uinfo->count = master->info.count;
 290         uinfo->value.integer.min = master->info.min_val;
 291         uinfo->value.integer.max = master->info.max_val;
 292         return 0;
 293 }
 294
 295 static int master_get(struct snd_kcontrol *kcontrol,
 296                       struct snd_ctl_elem_value *ucontrol)
 297 {
 298         struct link_master *master = snd_kcontrol_chip(kcontrol);
 299         int err = master_init(master);
 300         if (err < 0)
 301                 return err;
 302         ucontrol->value.integer.value[0] = master->val;
 303         return 0;
 304 }
 305
 306 static int master_put(struct snd_kcontrol *kcontrol,
 307                       struct snd_ctl_elem_value *ucontrol)
 308 {
 309         struct link_master *master = snd_kcontrol_chip(kcontrol);
 310         struct link_slave *slave;
 311         struct snd_ctl_elem_value *uval;
 312         int err, old_val;
 313
 314         err = master_init(master);
 315         if (err < 0)
 316                 return err;
 317         old_val = master->val;
 318         if (ucontrol->value.integer.value[0] == old_val)
 319                 return 0;
 320
 321         uval = kmalloc(sizeof(*uval), GFP_KERNEL);
 322         if (!uval)
 323                 return -ENOMEM;
 324         list_for_each_entry(slave, &master->slaves, list) {
 325                 master->val = old_val;
 326                 uval->id = slave->slave.id;
 327                 slave_get_val(slave, uval);
 328                 master->val = ucontrol->value.integer.value[0];
 329                 slave_put_val(slave, uval);
 330         }
 331         kfree(uval);
 332         return 1;
 333 }
 334
 335 static void master_free(struct snd_kcontrol *kcontrol)
 336 {
 337         struct link_master *master = snd_kcontrol_chip(kcontrol);
 338         struct link_slave *slave, *n;
 339
 340         /* free all slave links and retore the original slave kctls */
 341         list_for_each_entry_safe(slave, n, &master->slaves, list) {
 342                 struct snd_kcontrol *sctl = slave->kctl;
 343                 struct list_head olist = sctl->list;
 344                 memcpy(sctl, &slave->slave, sizeof(*sctl));
 345                 memcpy(sctl->vd, slave->slave.vd,
 346                        sctl->count * sizeof(*sctl->vd));
 347                 sctl->list = olist; /* keep the current linked-list */
 348                 kfree(slave);
 349         }
 350         kfree(master);
 351 }
 352
 353
 354 /**
 355  * snd_ctl_make_virtual_master - Create a virtual master control
 356  * @name: name string of the control element to create
 357  * @tlv: optional TLV int array for dB information
 358  *
 359  * Creates a virtual matster control with the given name string.
 360  * Returns the created control element, or NULL for errors (ENOMEM).
 361  *
 362  * After creating a vmaster element, you can add the slave controls
 363  * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
 364  *
 365  * The optional argument @tlv can be used to specify the TLV information
 366  * for dB scale of the master control.  It should be a single element
 367  * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
 368  * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
 369  */
 370 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 371                                                  const unsigned int *tlv)
 372 {
 373         struct link_master *master;
 374         struct snd_kcontrol *kctl;
 375         struct snd_kcontrol_new knew;
 376
 377         memset(&knew, 0, sizeof(knew));
 378         knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 379         knew.name = name;
 380         knew.info = master_info;
 381
 382         master = kzalloc(sizeof(*master), GFP_KERNEL);
 383         if (!master)
 384                 return NULL;
 385         INIT_LIST_HEAD(&master->slaves);
 386
 387         kctl = snd_ctl_new1(&knew, master);
 388         if (!kctl) {
 389                 kfree(master);
 390                 return NULL;
 391         }
 392         /* override some callbacks */
 393         kctl->info = master_info;
 394         kctl->get = master_get;
 395         kctl->put = master_put;
 396         kctl->private_free = master_free;
 397
 398         /* additional (constant) TLV read */
 399         if (tlv &&
 400             (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
 401              tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
 402              tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
 403                 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
 404                 memcpy(master->tlv, tlv, sizeof(master->tlv));
 405                 kctl->tlv.p = master->tlv;
 406         }
 407
 408         return kctl;
 409 }
 410 EXPORT_SYMBOL(snd_ctl_make_virtual_master);