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 */
43 * link slave - this contains a slave control element
45 * It fakes the control callbacsk with additional attenuation by the
46 * master control. A slave may have either one or two channels.
50 struct list_head list;
51 struct link_master *master;
52 struct link_ctl_info info;
53 int vals[2]; /* current values */
55 struct snd_kcontrol *kctl; /* original kcontrol pointer */
56 struct snd_kcontrol slave; /* the copy of original control entry */
59 static int slave_update(struct link_slave *slave)
61 struct snd_ctl_elem_value *uctl;
64 uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
67 uctl->id = slave->slave.id;
68 err = slave->slave.get(&slave->slave, uctl);
69 for (ch = 0; ch < slave->info.count; ch++)
70 slave->vals[ch] = uctl->value.integer.value[ch];
75 /* get the slave ctl info and save the initial values */
76 static int slave_init(struct link_slave *slave)
78 struct snd_ctl_elem_info *uinfo;
81 if (slave->info.count) {
82 /* already initialized */
83 if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
84 return slave_update(slave);
88 uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
91 uinfo->id = slave->slave.id;
92 err = slave->slave.info(&slave->slave, uinfo);
97 slave->info.type = uinfo->type;
98 slave->info.count = uinfo->count;
99 if (slave->info.count > 2 ||
100 (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
101 slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
102 snd_printk(KERN_ERR "invalid slave element\n");
106 slave->info.min_val = uinfo->value.integer.min;
107 slave->info.max_val = uinfo->value.integer.max;
110 return slave_update(slave);
113 /* initialize master volume */
114 static int master_init(struct link_master *master)
116 struct link_slave *slave;
118 if (master->info.count)
119 return 0; /* already initialized */
121 list_for_each_entry(slave, &master->slaves, list) {
122 int err = slave_init(slave);
125 master->info = slave->info;
126 master->info.count = 1; /* always mono */
127 /* set full volume as default (= no attenuation) */
128 master->val = master->info.max_val;
134 static int slave_get_val(struct link_slave *slave,
135 struct snd_ctl_elem_value *ucontrol)
139 err = slave_init(slave);
142 for (ch = 0; ch < slave->info.count; ch++)
143 ucontrol->value.integer.value[ch] = slave->vals[ch];
147 static int slave_put_val(struct link_slave *slave,
148 struct snd_ctl_elem_value *ucontrol)
152 err = master_init(slave->master);
156 switch (slave->info.type) {
157 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
158 for (ch = 0; ch < slave->info.count; ch++)
159 ucontrol->value.integer.value[ch] &=
160 !!slave->master->val;
162 case SNDRV_CTL_ELEM_TYPE_INTEGER:
163 for (ch = 0; ch < slave->info.count; ch++) {
164 /* max master volume is supposed to be 0 dB */
165 vol = ucontrol->value.integer.value[ch];
166 vol += slave->master->val - slave->master->info.max_val;
167 if (vol < slave->info.min_val)
168 vol = slave->info.min_val;
169 else if (vol > slave->info.max_val)
170 vol = slave->info.max_val;
171 ucontrol->value.integer.value[ch] = vol;
175 return slave->slave.put(&slave->slave, ucontrol);
179 * ctl callbacks for slaves
181 static int slave_info(struct snd_kcontrol *kcontrol,
182 struct snd_ctl_elem_info *uinfo)
184 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
185 return slave->slave.info(&slave->slave, uinfo);
188 static int slave_get(struct snd_kcontrol *kcontrol,
189 struct snd_ctl_elem_value *ucontrol)
191 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
192 return slave_get_val(slave, ucontrol);
195 static int slave_put(struct snd_kcontrol *kcontrol,
196 struct snd_ctl_elem_value *ucontrol)
198 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
199 int err, ch, changed = 0;
201 err = slave_init(slave);
204 for (ch = 0; ch < slave->info.count; ch++) {
205 if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
207 slave->vals[ch] = ucontrol->value.integer.value[ch];
212 return slave_put_val(slave, ucontrol);
215 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
216 int op_flag, unsigned int size,
217 unsigned int __user *tlv)
219 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
220 /* FIXME: this assumes that the max volume is 0 dB */
221 return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
224 static void slave_free(struct snd_kcontrol *kcontrol)
226 struct link_slave *slave = snd_kcontrol_chip(kcontrol);
227 if (slave->slave.private_free)
228 slave->slave.private_free(&slave->slave);
230 list_del(&slave->list);
235 * Add a slave control to the group with the given master control
237 * All slaves must be the same type (returning the same information
238 * via info callback). The function doesn't check it, so it's your
241 * Also, some additional limitations:
242 * - at most two channels
243 * - logarithmic volume control (dB level), no linear volume
244 * - master can only attenuate the volume, no gain
246 int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
249 struct link_master *master_link = snd_kcontrol_chip(master);
250 struct link_slave *srec;
252 srec = kzalloc(sizeof(*srec) +
253 slave->count * sizeof(*slave->vd), GFP_KERNEL);
257 srec->slave = *slave;
258 memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
259 srec->master = master_link;
262 /* override callbacks */
263 slave->info = slave_info;
264 slave->get = slave_get;
265 slave->put = slave_put;
266 if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
267 slave->tlv.c = slave_tlv_cmd;
268 slave->private_data = srec;
269 slave->private_free = slave_free;
271 list_add_tail(&srec->list, &master_link->slaves);
274 EXPORT_SYMBOL(_snd_ctl_add_slave);
277 * ctl callbacks for master controls
279 static int master_info(struct snd_kcontrol *kcontrol,
280 struct snd_ctl_elem_info *uinfo)
282 struct link_master *master = snd_kcontrol_chip(kcontrol);
285 ret = master_init(master);
288 uinfo->type = master->info.type;
289 uinfo->count = master->info.count;
290 uinfo->value.integer.min = master->info.min_val;
291 uinfo->value.integer.max = master->info.max_val;
295 static int master_get(struct snd_kcontrol *kcontrol,
296 struct snd_ctl_elem_value *ucontrol)
298 struct link_master *master = snd_kcontrol_chip(kcontrol);
299 int err = master_init(master);
302 ucontrol->value.integer.value[0] = master->val;
306 static int master_put(struct snd_kcontrol *kcontrol,
307 struct snd_ctl_elem_value *ucontrol)
309 struct link_master *master = snd_kcontrol_chip(kcontrol);
310 struct link_slave *slave;
311 struct snd_ctl_elem_value *uval;
314 err = master_init(master);
317 old_val = master->val;
318 if (ucontrol->value.integer.value[0] == old_val)
321 uval = kmalloc(sizeof(*uval), GFP_KERNEL);
324 list_for_each_entry(slave, &master->slaves, list) {
325 master->val = old_val;
326 uval->id = slave->slave.id;
327 slave_get_val(slave, uval);
328 master->val = ucontrol->value.integer.value[0];
329 slave_put_val(slave, uval);
335 static void master_free(struct snd_kcontrol *kcontrol)
337 struct link_master *master = snd_kcontrol_chip(kcontrol);
338 struct link_slave *slave, *n;
340 /* free all slave links and retore the original slave kctls */
341 list_for_each_entry_safe(slave, n, &master->slaves, list) {
342 struct snd_kcontrol *sctl = slave->kctl;
343 struct list_head olist = sctl->list;
344 memcpy(sctl, &slave->slave, sizeof(*sctl));
345 memcpy(sctl->vd, slave->slave.vd,
346 sctl->count * sizeof(*sctl->vd));
347 sctl->list = olist; /* keep the current linked-list */
355 * snd_ctl_make_virtual_master - Create a virtual master control
356 * @name: name string of the control element to create
357 * @tlv: optional TLV int array for dB information
359 * Creates a virtual matster control with the given name string.
360 * Returns the created control element, or NULL for errors (ENOMEM).
362 * After creating a vmaster element, you can add the slave controls
363 * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
365 * The optional argument @tlv can be used to specify the TLV information
366 * for dB scale of the master control. It should be a single element
367 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
368 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
370 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
371 const unsigned int *tlv)
373 struct link_master *master;
374 struct snd_kcontrol *kctl;
375 struct snd_kcontrol_new knew;
377 memset(&knew, 0, sizeof(knew));
378 knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
380 knew.info = master_info;
382 master = kzalloc(sizeof(*master), GFP_KERNEL);
385 INIT_LIST_HEAD(&master->slaves);
387 kctl = snd_ctl_new1(&knew, master);
392 /* override some callbacks */
393 kctl->info = master_info;
394 kctl->get = master_get;
395 kctl->put = master_put;
396 kctl->private_free = master_free;
398 /* additional (constant) TLV read */
400 (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
401 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
402 tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
403 kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
404 memcpy(master->tlv, tlv, sizeof(master->tlv));
405 kctl->tlv.p = master->tlv;
410 EXPORT_SYMBOL(snd_ctl_make_virtual_master);