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 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 51 struct 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 61 static 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 */ 78 static 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 */ 116 static 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 } 137 138 static 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 } 150 151 static 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 */ 185 static 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 } 191 192 static 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 } 198 199 static 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 } 218 219 static 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 } 227 228 static 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 */ 250 int _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 } 278 EXPORT_SYMBOL(_snd_ctl_add_slave); 279 280 /* 281 * ctl callbacks for master controls 282 */ 283 static 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 } 298 299 static 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 } 309 310 static 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 } 340 341 static 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 */ 376 struct 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 } 416 EXPORT_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 */ 427 int 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 } 436 EXPORT_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 */ 446 void 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 } 455 EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster_hook); 456