Root/sound/core/vmaster.c

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 */
20struct link_ctl_info {
21    snd_ctl_elem_type_t 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 */
34struct 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
48struct 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
57static 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 */
74static 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 */
112static 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
132static 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
145static 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 */
179static 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
186static 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
193static 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
213static 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
222static 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 function 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 */
244int _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}
271EXPORT_SYMBOL(_snd_ctl_add_slave);
272
273/*
274 * ctl callbacks for master controls
275 */
276static 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
292static 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
303static 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
332static 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 */
359struct 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}
399EXPORT_SYMBOL(snd_ctl_make_virtual_master);
400

Archive Download this file



interactive