linux/sound/core/vmaster.c
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   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 */
  21struct 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 */
  35struct 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        void (*hook)(void *private_data, int);
  41        void *hook_private_data;
  42};
  43
  44/*
  45 * link slave - this contains a slave control element
  46 *
  47 * It fakes the control callbacsk with additional attenuation by the
  48 * master control.  A slave may have either one or two channels.
  49 */
  50
  51struct link_slave {
  52        struct list_head list;
  53        struct link_master *master;
  54        struct link_ctl_info info;
  55        int vals[2];            /* current values */
  56        unsigned int flags;
  57        struct snd_kcontrol *kctl; /* original kcontrol pointer */
  58        struct snd_kcontrol slave; /* the copy of original control entry */
  59};
  60
  61static int slave_update(struct link_slave *slave)
  62{
  63        struct snd_ctl_elem_value *uctl;
  64        int err, ch;
  65
  66        uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
  67        if (!uctl)
  68                return -ENOMEM;
  69        uctl->id = slave->slave.id;
  70        err = slave->slave.get(&slave->slave, uctl);
  71        for (ch = 0; ch < slave->info.count; ch++)
  72                slave->vals[ch] = uctl->value.integer.value[ch];
  73        kfree(uctl);
  74        return 0;
  75}
  76
  77/* get the slave ctl info and save the initial values */
  78static int slave_init(struct link_slave *slave)
  79{
  80        struct snd_ctl_elem_info *uinfo;
  81        int err;
  82
  83        if (slave->info.count) {
  84                /* already initialized */
  85                if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
  86                        return slave_update(slave);
  87                return 0;
  88        }
  89
  90        uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
  91        if (!uinfo)
  92                return -ENOMEM;
  93        uinfo->id = slave->slave.id;
  94        err = slave->slave.info(&slave->slave, uinfo);
  95        if (err < 0) {
  96                kfree(uinfo);
  97                return err;
  98        }
  99        slave->info.type = uinfo->type;
 100        slave->info.count = uinfo->count;
 101        if (slave->info.count > 2  ||
 102            (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
 103             slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
 104                snd_printk(KERN_ERR "invalid slave element\n");
 105                kfree(uinfo);
 106                return -EINVAL;
 107        }
 108        slave->info.min_val = uinfo->value.integer.min;
 109        slave->info.max_val = uinfo->value.integer.max;
 110        kfree(uinfo);
 111
 112        return slave_update(slave);
 113}
 114
 115/* initialize master volume */
 116static int master_init(struct link_master *master)
 117{
 118        struct link_slave *slave;
 119
 120        if (master->info.count)
 121                return 0; /* already initialized */
 122
 123        list_for_each_entry(slave, &master->slaves, list) {
 124                int err = slave_init(slave);
 125                if (err < 0)
 126                        return err;
 127                master->info = slave->info;
 128                master->info.count = 1; /* always mono */
 129                /* set full volume as default (= no attenuation) */
 130                master->val = master->info.max_val;
 131                if (master->hook)
 132                        master->hook(master->hook_private_data, master->val);
 133                return 1;
 134        }
 135        return -ENOENT;
 136}
 137
 138static int slave_get_val(struct link_slave *slave,
 139                         struct snd_ctl_elem_value *ucontrol)
 140{
 141        int err, ch;
 142
 143        err = slave_init(slave);
 144        if (err < 0)
 145                return err;
 146        for (ch = 0; ch < slave->info.count; ch++)
 147                ucontrol->value.integer.value[ch] = slave->vals[ch];
 148        return 0;
 149}
 150
 151static int slave_put_val(struct link_slave *slave,
 152                         struct snd_ctl_elem_value *ucontrol)
 153{
 154        int err, ch, vol;
 155
 156        err = master_init(slave->master);
 157        if (err < 0)
 158                return err;
 159
 160        switch (slave->info.type) {
 161        case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 162                for (ch = 0; ch < slave->info.count; ch++)
 163                        ucontrol->value.integer.value[ch] &=
 164                                !!slave->master->val;
 165                break;
 166        case SNDRV_CTL_ELEM_TYPE_INTEGER:
 167                for (ch = 0; ch < slave->info.count; ch++) {
 168                        /* max master volume is supposed to be 0 dB */
 169                        vol = ucontrol->value.integer.value[ch];
 170                        vol += slave->master->val - slave->master->info.max_val;
 171                        if (vol < slave->info.min_val)
 172                                vol = slave->info.min_val;
 173                        else if (vol > slave->info.max_val)
 174                                vol = slave->info.max_val;
 175                        ucontrol->value.integer.value[ch] = vol;
 176                }
 177                break;
 178        }
 179        return slave->slave.put(&slave->slave, ucontrol);
 180}
 181
 182/*
 183 * ctl callbacks for slaves
 184 */
 185static int slave_info(struct snd_kcontrol *kcontrol,
 186                      struct snd_ctl_elem_info *uinfo)
 187{
 188        struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 189        return slave->slave.info(&slave->slave, uinfo);
 190}
 191
 192static int slave_get(struct snd_kcontrol *kcontrol,
 193                     struct snd_ctl_elem_value *ucontrol)
 194{
 195        struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 196        return slave_get_val(slave, ucontrol);
 197}
 198
 199static int slave_put(struct snd_kcontrol *kcontrol,
 200                     struct snd_ctl_elem_value *ucontrol)
 201{
 202        struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 203        int err, ch, changed = 0;
 204
 205        err = slave_init(slave);
 206        if (err < 0)
 207                return err;
 208        for (ch = 0; ch < slave->info.count; ch++) {
 209                if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
 210                        changed = 1;
 211                        slave->vals[ch] = ucontrol->value.integer.value[ch];
 212                }
 213        }
 214        if (!changed)
 215                return 0;
 216        return slave_put_val(slave, ucontrol);
 217}
 218
 219static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
 220                         int op_flag, unsigned int size,
 221                         unsigned int __user *tlv)
 222{
 223        struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 224        /* FIXME: this assumes that the max volume is 0 dB */
 225        return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
 226}
 227
 228static void slave_free(struct snd_kcontrol *kcontrol)
 229{
 230        struct link_slave *slave = snd_kcontrol_chip(kcontrol);
 231        if (slave->slave.private_free)
 232                slave->slave.private_free(&slave->slave);
 233        if (slave->master)
 234                list_del(&slave->list);
 235        kfree(slave);
 236}
 237
 238/*
 239 * Add a slave control to the group with the given master control
 240 *
 241 * All slaves must be the same type (returning the same information
 242 * via info callback).  The function doesn't check it, so it's your
 243 * responsibility.
 244 *
 245 * Also, some additional limitations:
 246 * - at most two channels
 247 * - logarithmic volume control (dB level), no linear volume
 248 * - master can only attenuate the volume, no gain
 249 */
 250int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
 251                       unsigned int flags)
 252{
 253        struct link_master *master_link = snd_kcontrol_chip(master);
 254        struct link_slave *srec;
 255
 256        srec = kzalloc(sizeof(*srec) +
 257                       slave->count * sizeof(*slave->vd), GFP_KERNEL);
 258        if (!srec)
 259                return -ENOMEM;
 260        srec->kctl = slave;
 261        srec->slave = *slave;
 262        memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
 263        srec->master = master_link;
 264        srec->flags = flags;
 265
 266        /* override callbacks */
 267        slave->info = slave_info;
 268        slave->get = slave_get;
 269        slave->put = slave_put;
 270        if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
 271                slave->tlv.c = slave_tlv_cmd;
 272        slave->private_data = srec;
 273        slave->private_free = slave_free;
 274
 275        list_add_tail(&srec->list, &master_link->slaves);
 276        return 0;
 277}
 278EXPORT_SYMBOL(_snd_ctl_add_slave);
 279
 280/*
 281 * ctl callbacks for master controls
 282 */
 283static int master_info(struct snd_kcontrol *kcontrol,
 284                      struct snd_ctl_elem_info *uinfo)
 285{
 286        struct link_master *master = snd_kcontrol_chip(kcontrol);
 287        int ret;
 288
 289        ret = master_init(master);
 290        if (ret < 0)
 291                return ret;
 292        uinfo->type = master->info.type;
 293        uinfo->count = master->info.count;
 294        uinfo->value.integer.min = master->info.min_val;
 295        uinfo->value.integer.max = master->info.max_val;
 296        return 0;
 297}
 298
 299static int master_get(struct snd_kcontrol *kcontrol,
 300                      struct snd_ctl_elem_value *ucontrol)
 301{
 302        struct link_master *master = snd_kcontrol_chip(kcontrol);
 303        int err = master_init(master);
 304        if (err < 0)
 305                return err;
 306        ucontrol->value.integer.value[0] = master->val;
 307        return 0;
 308}
 309
 310static int master_put(struct snd_kcontrol *kcontrol,
 311                      struct snd_ctl_elem_value *ucontrol)
 312{
 313        struct link_master *master = snd_kcontrol_chip(kcontrol);
 314        struct link_slave *slave;
 315        struct snd_ctl_elem_value *uval;
 316        int err, old_val;
 317
 318        err = master_init(master);
 319        if (err < 0)
 320                return err;
 321        old_val = master->val;
 322        if (ucontrol->value.integer.value[0] == old_val)
 323                return 0;
 324
 325        uval = kmalloc(sizeof(*uval), GFP_KERNEL);
 326        if (!uval)
 327                return -ENOMEM;
 328        list_for_each_entry(slave, &master->slaves, list) {
 329                master->val = old_val;
 330                uval->id = slave->slave.id;
 331                slave_get_val(slave, uval);
 332                master->val = ucontrol->value.integer.value[0];
 333                slave_put_val(slave, uval);
 334        }
 335        kfree(uval);
 336        if (master->hook && !err)
 337                master->hook(master->hook_private_data, master->val);
 338        return 1;
 339}
 340
 341static void master_free(struct snd_kcontrol *kcontrol)
 342{
 343        struct link_master *master = snd_kcontrol_chip(kcontrol);
 344        struct link_slave *slave, *n;
 345
 346        /* free all slave links and retore the original slave kctls */
 347        list_for_each_entry_safe(slave, n, &master->slaves, list) {
 348                struct snd_kcontrol *sctl = slave->kctl;
 349                struct list_head olist = sctl->list;
 350                memcpy(sctl, &slave->slave, sizeof(*sctl));
 351                memcpy(sctl->vd, slave->slave.vd,
 352                       sctl->count * sizeof(*sctl->vd));
 353                sctl->list = olist; /* keep the current linked-list */
 354                kfree(slave);
 355        }
 356        kfree(master);
 357}
 358
 359
 360/**
 361 * snd_ctl_make_virtual_master - Create a virtual master control
 362 * @name: name string of the control element to create
 363 * @tlv: optional TLV int array for dB information
 364 *
 365 * Creates a virtual matster control with the given name string.
 366 * Returns the created control element, or NULL for errors (ENOMEM).
 367 *
 368 * After creating a vmaster element, you can add the slave controls
 369 * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
 370 *
 371 * The optional argument @tlv can be used to specify the TLV information
 372 * for dB scale of the master control.  It should be a single element
 373 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
 374 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
 375 */
 376struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 377                                                 const unsigned int *tlv)
 378{
 379        struct link_master *master;
 380        struct snd_kcontrol *kctl;
 381        struct snd_kcontrol_new knew;
 382
 383        memset(&knew, 0, sizeof(knew));
 384        knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 385        knew.name = name;
 386        knew.info = master_info;
 387
 388        master = kzalloc(sizeof(*master), GFP_KERNEL);
 389        if (!master)
 390                return NULL;
 391        INIT_LIST_HEAD(&master->slaves);
 392
 393        kctl = snd_ctl_new1(&knew, master);
 394        if (!kctl) {
 395                kfree(master);
 396                return NULL;
 397        }
 398        /* override some callbacks */
 399        kctl->info = master_info;
 400        kctl->get = master_get;
 401        kctl->put = master_put;
 402        kctl->private_free = master_free;
 403
 404        /* additional (constant) TLV read */
 405        if (tlv &&
 406            (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
 407             tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
 408             tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
 409                kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
 410                memcpy(master->tlv, tlv, sizeof(master->tlv));
 411                kctl->tlv.p = master->tlv;
 412        }
 413
 414        return kctl;
 415}
 416EXPORT_SYMBOL(snd_ctl_make_virtual_master);
 417
 418/**
 419 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
 420 * @kcontrol: vmaster kctl element
 421 * @hook: the hook function
 422 * @private_data: the private_data pointer to be saved
 423 *
 424 * Adds the given hook to the vmaster control element so that it's called
 425 * at each time when the value is changed.
 426 */
 427int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
 428                             void (*hook)(void *private_data, int),
 429                             void *private_data)
 430{
 431        struct link_master *master = snd_kcontrol_chip(kcontrol);
 432        master->hook = hook;
 433        master->hook_private_data = private_data;
 434        return 0;
 435}
 436EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
 437
 438/**
 439 * snd_ctl_sync_vmaster_hook - Sync the vmaster hook
 440 * @kcontrol: vmaster kctl element
 441 *
 442 * Call the hook function to synchronize with the current value of the given
 443 * vmaster element.  NOP when NULL is passed to @kcontrol or the hook doesn't
 444 * exist.
 445 */
 446void snd_ctl_sync_vmaster_hook(struct snd_kcontrol *kcontrol)
 447{
 448        struct link_master *master;
 449        if (!kcontrol)
 450                return;
 451        master = snd_kcontrol_chip(kcontrol);
 452        if (master->hook)
 453                master->hook(master->hook_private_data, master->val);
 454}
 455EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster_hook);
 456
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