2 * Virtual master and slave controls
4 * Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
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.
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>
19 * a subset of information returned via ctl info callback
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 */
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.
32 * The master control is so far only mono volume/switch for simplicity.
33 * The same value will be applied to all slaves.
36 struct list_head slaves;
37 struct link_ctl_info info;
38 int val; /* the master value */
40 void (*hook)(void *private_data, int);
41 void *hook_private_data;
45 * link slave - this contains a slave control element
47 * It fakes the control callbacsk with additional attenuation by the
48 * master control. A slave may have either one or two channels.
52 struct list_head list;
53 struct link_master *master;
54 struct link_ctl_info info;
55 int vals[2]; /* current values */
57 struct snd_kcontrol *kctl; /* original kcontrol pointer */
58 struct snd_kcontrol slave; /* the copy of original control entry */
61 static int slave_update(struct link_slave *slave)
63 struct snd_ctl_elem_value *uctl;
66 uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
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];
77 /* get the slave ctl info and save the initial values */
78 static int slave_init(struct link_slave *slave)
80 struct snd_ctl_elem_info *uinfo;
83 if (slave->info.count) {
84 /* already initialized */
85 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
86 return slave_update(slave);
90 uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
93 uinfo->id = slave->slave.id;
94 err = slave->slave.info(&slave->slave, uinfo);
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 pr_err("ALSA: vmaster: invalid slave element\n");
108 slave->info.min_val = uinfo->value.integer.min;
109 slave->info.max_val = uinfo->value.integer.max;
112 return slave_update(slave);
115 /* initialize master volume */
116 static int master_init(struct link_master *master)
118 struct link_slave *slave;
120 if (master->info.count)
121 return 0; /* already initialized */
123 list_for_each_entry(slave, &master->slaves, list) {
124 int err = slave_init(slave);
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;
132 master->hook(master->hook_private_data, master->val);
138 static int slave_get_val(struct link_slave *slave,
139 struct snd_ctl_elem_value *ucontrol)
143 err = slave_init(slave);
146 for (ch = 0; ch < slave->info.count; ch++)
147 ucontrol->value.integer.value[ch] = slave->vals[ch];
151 static int slave_put_val(struct link_slave *slave,
152 struct snd_ctl_elem_value *ucontrol)
156 err = master_init(slave->master);
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;
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;
179 return slave->slave.put(&slave->slave, ucontrol);
183 * ctl callbacks for slaves
185 static int slave_info(struct snd_kcontrol *kcontrol,
186 struct snd_ctl_elem_info *uinfo)
188 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
189 return slave->slave.info(&slave->slave, uinfo);
192 static int slave_get(struct snd_kcontrol *kcontrol,
193 struct snd_ctl_elem_value *ucontrol)
195 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
196 return slave_get_val(slave, ucontrol);
199 static int slave_put(struct snd_kcontrol *kcontrol,
200 struct snd_ctl_elem_value *ucontrol)
202 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
203 int err, ch, changed = 0;
205 err = slave_init(slave);
208 for (ch = 0; ch < slave->info.count; ch++) {
209 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
211 slave->vals[ch] = ucontrol->value.integer.value[ch];
216 err = slave_put_val(slave, ucontrol);
222 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
223 int op_flag, unsigned int size,
224 unsigned int __user *tlv)
226 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
227 /* FIXME: this assumes that the max volume is 0 dB */
228 return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
231 static void slave_free(struct snd_kcontrol *kcontrol)
233 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
234 if (slave->slave.private_free)
235 slave->slave.private_free(&slave->slave);
237 list_del(&slave->list);
242 * Add a slave control to the group with the given master control
244 * All slaves must be the same type (returning the same information
245 * via info callback). The function doesn't check it, so it's your
248 * Also, some additional limitations:
249 * - at most two channels
250 * - logarithmic volume control (dB level), no linear volume
251 * - master can only attenuate the volume, no gain
253 int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
256 struct link_master *master_link = snd_kcontrol_chip(master);
257 struct link_slave *srec;
259 srec = kzalloc(sizeof(*srec) +
260 slave->count * sizeof(*slave->vd), GFP_KERNEL);
264 srec->slave = *slave;
265 memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
266 srec->master = master_link;
269 /* override callbacks */
270 slave->info = slave_info;
271 slave->get = slave_get;
272 slave->put = slave_put;
273 if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
274 slave->tlv.c = slave_tlv_cmd;
275 slave->private_data = srec;
276 slave->private_free = slave_free;
278 list_add_tail(&srec->list, &master_link->slaves);
281 EXPORT_SYMBOL(_snd_ctl_add_slave);
284 * ctl callbacks for master controls
286 static int master_info(struct snd_kcontrol *kcontrol,
287 struct snd_ctl_elem_info *uinfo)
289 struct link_master *master = snd_kcontrol_chip(kcontrol);
292 ret = master_init(master);
295 uinfo->type = master->info.type;
296 uinfo->count = master->info.count;
297 uinfo->value.integer.min = master->info.min_val;
298 uinfo->value.integer.max = master->info.max_val;
302 static int master_get(struct snd_kcontrol *kcontrol,
303 struct snd_ctl_elem_value *ucontrol)
305 struct link_master *master = snd_kcontrol_chip(kcontrol);
306 int err = master_init(master);
309 ucontrol->value.integer.value[0] = master->val;
313 static int sync_slaves(struct link_master *master, int old_val, int new_val)
315 struct link_slave *slave;
316 struct snd_ctl_elem_value *uval;
318 uval = kmalloc(sizeof(*uval), GFP_KERNEL);
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 = new_val;
326 slave_put_val(slave, uval);
332 static int master_put(struct snd_kcontrol *kcontrol,
333 struct snd_ctl_elem_value *ucontrol)
335 struct link_master *master = snd_kcontrol_chip(kcontrol);
336 int err, new_val, old_val;
339 err = master_init(master);
343 old_val = master->val;
344 new_val = ucontrol->value.integer.value[0];
345 if (new_val == old_val)
348 err = sync_slaves(master, old_val, new_val);
351 if (master->hook && !first_init)
352 master->hook(master->hook_private_data, master->val);
356 static void master_free(struct snd_kcontrol *kcontrol)
358 struct link_master *master = snd_kcontrol_chip(kcontrol);
359 struct link_slave *slave, *n;
361 /* free all slave links and retore the original slave kctls */
362 list_for_each_entry_safe(slave, n, &master->slaves, list) {
363 struct snd_kcontrol *sctl = slave->kctl;
364 struct list_head olist = sctl->list;
365 memcpy(sctl, &slave->slave, sizeof(*sctl));
366 memcpy(sctl->vd, slave->slave.vd,
367 sctl->count * sizeof(*sctl->vd));
368 sctl->list = olist; /* keep the current linked-list */
376 * snd_ctl_make_virtual_master - Create a virtual master control
377 * @name: name string of the control element to create
378 * @tlv: optional TLV int array for dB information
380 * Creates a virtual master control with the given name string.
382 * After creating a vmaster element, you can add the slave controls
383 * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
385 * The optional argument @tlv can be used to specify the TLV information
386 * for dB scale of the master control. It should be a single element
387 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
388 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
390 * Return: The created control element, or %NULL for errors (ENOMEM).
392 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
393 const unsigned int *tlv)
395 struct link_master *master;
396 struct snd_kcontrol *kctl;
397 struct snd_kcontrol_new knew;
399 memset(&knew, 0, sizeof(knew));
400 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
402 knew.info = master_info;
404 master = kzalloc(sizeof(*master), GFP_KERNEL);
407 INIT_LIST_HEAD(&master->slaves);
409 kctl = snd_ctl_new1(&knew, master);
414 /* override some callbacks */
415 kctl->info = master_info;
416 kctl->get = master_get;
417 kctl->put = master_put;
418 kctl->private_free = master_free;
420 /* additional (constant) TLV read */
422 (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
423 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
424 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
425 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
426 memcpy(master->tlv, tlv, sizeof(master->tlv));
427 kctl->tlv.p = master->tlv;
432 EXPORT_SYMBOL(snd_ctl_make_virtual_master);
435 * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
436 * @kcontrol: vmaster kctl element
437 * @hook: the hook function
438 * @private_data: the private_data pointer to be saved
440 * Adds the given hook to the vmaster control element so that it's called
441 * at each time when the value is changed.
445 int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
446 void (*hook)(void *private_data, int),
449 struct link_master *master = snd_kcontrol_chip(kcontrol);
451 master->hook_private_data = private_data;
454 EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
457 * snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
458 * @kcontrol: vmaster kctl element
459 * @hook_only: sync only the hook
461 * Forcibly call the put callback of each slave and call the hook function
462 * to synchronize with the current value of the given vmaster element.
463 * NOP when NULL is passed to @kcontrol.
465 void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
467 struct link_master *master;
468 bool first_init = false;
472 master = snd_kcontrol_chip(kcontrol);
474 int err = master_init(master);
478 err = sync_slaves(master, master->val, master->val);
483 if (master->hook && !first_init)
484 master->hook(master->hook_private_data, master->val);
486 EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);