Linux Kernel  3.7.1
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vmaster.c
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1 /*
2  * Virtual master and slave controls
3  *
4  * Copyright (c) 2008 by Takashi Iwai <[email protected]>
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;
38  int val; /* the master value */
39  unsigned int tlv[4];
40  void (*hook)(void *private_data, int);
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;
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) {
162  for (ch = 0; ch < slave->info.count; ch++)
163  ucontrol->value.integer.value[ch] &=
164  !!slave->master->val;
165  break;
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 }
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 
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));
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 }
417 
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;
434  return 0;
435 }
437 
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 }