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, #SNDRV_CTL_TLV_DB_MINMAX or 357 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB. 358 */ 359 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name, 360 const unsigned int *tlv) 361 { 362 struct link_master *master; 363 struct snd_kcontrol *kctl; 364 struct snd_kcontrol_new knew; 365 366 memset(&knew, 0, sizeof(knew)); 367 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER; 368 knew.name = name; 369 knew.info = master_info; 370 371 master = kzalloc(sizeof(*master), GFP_KERNEL); 372 if (!master) 373 return NULL; 374 INIT_LIST_HEAD(&master->slaves); 375 376 kctl = snd_ctl_new1(&knew, master); 377 if (!kctl) { 378 kfree(master); 379 return NULL; 380 } 381 /* override some callbacks */ 382 kctl->info = master_info; 383 kctl->get = master_get; 384 kctl->put = master_put; 385 kctl->private_free = master_free; 386 387 /* additional (constant) TLV read */ 388 if (tlv && 389 (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE || 390 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX || 391 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) { 392 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ; 393 memcpy(master->tlv, tlv, sizeof(master->tlv)); 394 kctl->tlv.p = master->tlv; 395 } 396 397 return kctl; 398 } 399 EXPORT_SYMBOL(snd_ctl_make_virtual_master); 400