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 <sound/core.h>
  14 #include <sound/control.h>
  15 #include <sound/tlv.h>
  16
  17 /*
  18  * a subset of information returned via ctl info callback
  19  */
  20 struct link_ctl_info {
  21         int type;               /* value type */
  22         int count;              /* item count */
  23         int min_val, max_val;   /* min, max values */
  24 };
  25
  26 /*
  27  * link master - this contains a list of slave controls that are
  28  * identical types, i.e. info returns the same value type and value
  29  * ranges, but may have different number of counts.
  30  *
  31  * The master control is so far only mono volume/switch for simplicity.
  32  * The same value will be applied to all slaves.
  33  */
  34 struct link_master {
  35         struct list_head slaves;
  36         struct link_ctl_info info;
  37         int val;                /* the master value */
  38         unsigned int tlv[4];
  39 };
  40
  41 /*
  42  * link slave - this contains a slave control element
  43  *
  44  * It fakes the control callbacsk with additional attenuation by the
  45  * master control.  A slave may have either one or two channels.
  46  */
  47
  48 struct link_slave {
  49         struct list_head list;
  50         struct link_master *master;
  51         struct link_ctl_info info;
  52         int vals[2];            /* current values */
  53         unsigned int flags;
  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 = kmalloc(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         for (ch = 0; ch < slave->info.count; ch++)
  68                 slave->vals[ch] = uctl->value.integer.value[ch];
  69         kfree(uctl);
  70         return 0;
  71 }
  72
  73 /* get the slave ctl info and save the initial values */
  74 static int slave_init(struct link_slave *slave)
  75 {
  76         struct snd_ctl_elem_info *uinfo;
  77         int err;
  78
  79         if (slave->info.count) {
  80                 /* already initialized */
  81                 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
  82                         return slave_update(slave);
  83                 return 0;
  84         }
  85
  86         uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
  87         if (!uinfo)
  88                 return -ENOMEM;
  89         uinfo->id = slave->slave.id;
  90         err = slave->slave.info(&slave->slave, uinfo);
  91         if (err < 0) {
  92                 kfree(uinfo);
  93                 return err;
  94         }
  95         slave->info.type = uinfo->type;
  96         slave->info.count = uinfo->count;
  97         if (slave->info.count > 2  ||
  98             (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
  99              slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
 100                 snd_printk(KERN_ERR "invalid slave element\n");
 101                 kfree(uinfo);
 102                 return -EINVAL;
 103         }
 104         slave->info.min_val = uinfo->value.integer.min;
 105         slave->info.max_val = uinfo->value.integer.max;
 106         kfree(uinfo);
 107
 108         return slave_update(slave);
 109 }
 110
 111 /* initialize master volume */
 112 static int master_init(struct link_master *master)
 113 {
 114         struct link_slave *slave;
 115
 116         if (master->info.count)
 117                 return 0; /* already initialized */
 118
 119         list_for_each_entry(slave, &master->slaves, list) {
 120                 int err = slave_init(slave);
 121                 if (err < 0)
 122                         return err;
 123                 master->info = slave->info;
 124                 master->info.count = 1; /* always mono */
 125                 /* set full volume as default (= no attenuation) */
 126                 master->val = master->info.max_val;
 127                 return 0;
 128         }
 129         return -ENOENT;
 130 }
 131
 132 static int slave_get_val(struct link_slave *slave,
 133                          struct snd_ctl_elem_value *ucontrol)
 134 {
 135         int err, ch;
 136
 137         err = slave_init(slave);
 138         if (err < 0)
 139                 return err;
 140         for (ch = 0; ch < slave->info.count; ch++)
 141                 ucontrol->value.integer.value[ch] = slave->vals[ch];
 142         return 0;
 143 }
 144
 145 static int slave_put_val(struct link_slave *slave,
 146                          struct snd_ctl_elem_value *ucontrol)
 147 {
 148         int err, ch, vol;
 149
 150         err = master_init(slave->master);
 151         if (err < 0)
 152                 return err;
 153
 154         switch (slave->info.type) {
 155         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 156                 for (ch = 0; ch < slave->info.count; ch++)
 157                         ucontrol->value.integer.value[ch] &=
 158                                 !!slave->master->val;
 159                 break;
 160         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 161                 for (ch = 0; ch < slave->info.count; ch++) {
 162                         /* max master volume is supposed to be 0 dB */
 163                         vol = ucontrol->value.integer.value[ch];
 164                         vol += slave->master->val - slave->master->info.max_val;
 165                         if (vol < slave->info.min_val)
 166                                 vol = slave->info.min_val;
 167                         else if (vol > slave->info.max_val)
 168                                 vol = slave->info.max_val;
 169                         ucontrol->value.integer.value[ch] = vol;
 170                 }
 171                 break;
 172         }
 173         return slave->slave.put(&slave->slave, ucontrol);
 174 }
 175
 176 /*
 177  * ctl callbacks for slaves
 178  */
 179 static int slave_info(struct snd_kcontrol *kcontrol,
 180                       struct snd_ctl_elem_info *uinfo)
 181 {
 182         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 183         return slave->slave.info(&slave->slave, uinfo);
 184 }
 185
 186 static int slave_get(struct snd_kcontrol *kcontrol,
 187                      struct snd_ctl_elem_value *ucontrol)
 188 {
 189         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 190         return slave_get_val(slave, ucontrol);
 191 }
 192
 193 static int slave_put(struct snd_kcontrol *kcontrol,
 194                      struct snd_ctl_elem_value *ucontrol)
 195 {
 196         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 197         int err, ch, changed = 0;
 198
 199         err = slave_init(slave);
 200         if (err < 0)
 201                 return err;
 202         for (ch = 0; ch < slave->info.count; ch++) {
 203                 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
 204                         changed = 1;
 205                         slave->vals[ch] = ucontrol->value.integer.value[ch];
 206                 }
 207         }
 208         if (!changed)
 209                 return 0;
 210         return slave_put_val(slave, ucontrol);
 211 }
 212
 213 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
 214                          int op_flag, unsigned int size,
 215                          unsigned int __user *tlv)
 216 {
 217         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 218         /* FIXME: this assumes that the max volume is 0 dB */
 219         return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
 220 }
 221
 222 static void slave_free(struct snd_kcontrol *kcontrol)
 223 {
 224         struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 225         if (slave->slave.private_free)
 226                 slave->slave.private_free(&slave->slave);
 227         if (slave->master)
 228                 list_del(&slave->list);
 229         kfree(slave);
 230 }
 231
 232 /*
 233  * Add a slave control to the group with the given master control
 234  *
 235  * All slaves must be the same type (returning the same information
 236  * via info callback).  The fucntion doesn't check it, so it's your
 237  * responsibility.
 238  *
 239  * Also, some additional limitations:
 240  * - at most two channels
 241  * - logarithmic volume control (dB level), no linear volume
 242  * - master can only attenuate the volume, no gain
 243  */
 244 int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
 245                        unsigned int flags)
 246 {
 247         struct link_master *master_link = snd_kcontrol_chip(master);
 248         struct link_slave *srec;
 249
 250         srec = kzalloc(sizeof(*srec) +
 251                        slave->count * sizeof(*slave->vd), GFP_KERNEL);
 252         if (!srec)
 253                 return -ENOMEM;
 254         srec->slave = *slave;
 255         memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
 256         srec->master = master_link;
 257         srec->flags = flags;
 258
 259         /* override callbacks */
 260         slave->info = slave_info;
 261         slave->get = slave_get;
 262         slave->put = slave_put;
 263         if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
 264                 slave->tlv.c = slave_tlv_cmd;
 265         slave->private_data = srec;
 266         slave->private_free = slave_free;
 267
 268         list_add_tail(&srec->list, &master_link->slaves);
 269         return 0;
 270 }
 271 EXPORT_SYMBOL(_snd_ctl_add_slave);
 272
 273 /*
 274  * ctl callbacks for master controls
 275  */
 276 static int master_info(struct snd_kcontrol *kcontrol,
 277                       struct snd_ctl_elem_info *uinfo)
 278 {
 279         struct link_master *master = snd_kcontrol_chip(kcontrol);
 280         int ret;
 281
 282         ret = master_init(master);
 283         if (ret < 0)
 284                 return ret;
 285         uinfo->type = master->info.type;
 286         uinfo->count = master->info.count;
 287         uinfo->value.integer.min = master->info.min_val;
 288         uinfo->value.integer.max = master->info.max_val;
 289         return 0;
 290 }
 291
 292 static int master_get(struct snd_kcontrol *kcontrol,
 293                       struct snd_ctl_elem_value *ucontrol)
 294 {
 295         struct link_master *master = snd_kcontrol_chip(kcontrol);
 296         int err = master_init(master);
 297         if (err < 0)
 298                 return err;
 299         ucontrol->value.integer.value[0] = master->val;
 300         return 0;
 301 }
 302
 303 static int master_put(struct snd_kcontrol *kcontrol,
 304                       struct snd_ctl_elem_value *ucontrol)
 305 {
 306         struct link_master *master = snd_kcontrol_chip(kcontrol);
 307         struct link_slave *slave;
 308         struct snd_ctl_elem_value *uval;
 309         int err, old_val;
 310
 311         err = master_init(master);
 312         if (err < 0)
 313                 return err;
 314         old_val = master->val;
 315         if (ucontrol->value.integer.value[0] == old_val)
 316                 return 0;
 317
 318         uval = kmalloc(sizeof(*uval), GFP_KERNEL);
 319         if (!uval)
 320                 return -ENOMEM;
 321         list_for_each_entry(slave, &master->slaves, list) {
 322                 master->val = old_val;
 323                 uval->id = slave->slave.id;
 324                 slave_get_val(slave, uval);
 325                 master->val = ucontrol->value.integer.value[0];
 326                 slave_put_val(slave, uval);
 327         }
 328         kfree(uval);
 329         return 1;
 330 }
 331
 332 static void master_free(struct snd_kcontrol *kcontrol)
 333 {
 334         struct link_master *master = snd_kcontrol_chip(kcontrol);
 335         struct link_slave *slave;
 336
 337         list_for_each_entry(slave, &master->slaves, list)
 338                 slave->master = NULL;
 339         kfree(master);
 340 }
 341
 342
 343 /**
 344  * snd_ctl_make_virtual_master - Create a virtual master control
 345  * @name: name string of the control element to create
 346  * @tlv: optional TLV int array for dB information
 347  *
 348  * Creates a virtual matster control with the given name string.
 349  * Returns the created control element, or NULL for errors (ENOMEM).
 350  *
 351  * After creating a vmaster element, you can add the slave controls
 352  * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
 353  *
 354  * The optional argument @tlv can be used to specify the TLV information
 355  * for dB scale of the master control.  It should be a single element
 356  * with #SNDRV_CTL_TLVT_DB_SCALE type, and should be the max 0dB.
 357  */
 358 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 359                                                  const unsigned int *tlv)
 360 {
 361         struct link_master *master;
 362         struct snd_kcontrol *kctl;
 363         struct snd_kcontrol_new knew;
 364
 365         memset(&knew, 0, sizeof(knew));
 366         knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 367         knew.name = name;
 368         knew.info = master_info;
 369
 370         master = kzalloc(sizeof(*master), GFP_KERNEL);
 371         if (!master)
 372                 return NULL;
 373         INIT_LIST_HEAD(&master->slaves);
 374
 375         kctl = snd_ctl_new1(&knew, master);
 376         if (!kctl) {
 377                 kfree(master);
 378                 return NULL;
 379         }
 380         /* override some callbacks */
 381         kctl->info = master_info;
 382         kctl->get = master_get;
 383         kctl->put = master_put;
 384         kctl->private_free = master_free;
 385
 386         /* additional (constant) TLV read */
 387         if (tlv && tlv[0] == SNDRV_CTL_TLVT_DB_SCALE) {
 388                 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
 389                 memcpy(master->tlv, tlv, sizeof(master->tlv));
 390                 kctl->tlv.p = master->tlv;
 391         }
 392
 393         return kctl;
 394 }
 395 EXPORT_SYMBOL(snd_ctl_make_virtual_master);