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 <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 */
21struct 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 */
35struct link_master {
36	struct list_head slaves;
37	struct link_ctl_info info;
38	int val;		/* the master value */
39	unsigned int tlv[4];
40	void (*hook)(void *private_data, int);
41	void *hook_private_data;
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
51struct link_slave {
52	struct list_head list;
53	struct link_master *master;
54	struct link_ctl_info info;
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
61static 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 */
78static 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		pr_err("ALSA: vmaster: 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 */
116static 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
138static 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
151static 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) {
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;
165		break;
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;
176		}
177		break;
178	}
179	return slave->slave.put(&slave->slave, ucontrol);
180}
181
182/*
183 * ctl callbacks for slaves
184 */
185static 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
192static 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
199static 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	err = slave_put_val(slave, ucontrol);
217	if (err < 0)
218		return err;
219	return 1;
220}
221
222static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
223			 int op_flag, unsigned int size,
224			 unsigned int __user *tlv)
225{
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);
229}
230
231static void slave_free(struct snd_kcontrol *kcontrol)
232{
233	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
234	if (slave->slave.private_free)
235		slave->slave.private_free(&slave->slave);
236	if (slave->master)
237		list_del(&slave->list);
238	kfree(slave);
239}
240
241/*
242 * Add a slave control to the group with the given master control
243 *
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
246 * responsibility.
247 *
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
252 */
253int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
254		       unsigned int flags)
255{
256	struct link_master *master_link = snd_kcontrol_chip(master);
257	struct link_slave *srec;
258
259	srec = kzalloc(sizeof(*srec) +
260		       slave->count * sizeof(*slave->vd), GFP_KERNEL);
261	if (!srec)
262		return -ENOMEM;
263	srec->kctl = slave;
264	srec->slave = *slave;
265	memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
266	srec->master = master_link;
267	srec->flags = flags;
268
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;
277
278	list_add_tail(&srec->list, &master_link->slaves);
279	return 0;
280}
281EXPORT_SYMBOL(_snd_ctl_add_slave);
282
283/*
284 * ctl callbacks for master controls
285 */
286static int master_info(struct snd_kcontrol *kcontrol,
287		      struct snd_ctl_elem_info *uinfo)
288{
289	struct link_master *master = snd_kcontrol_chip(kcontrol);
290	int ret;
291
292	ret = master_init(master);
293	if (ret < 0)
294		return ret;
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;
299	return 0;
300}
301
302static int master_get(struct snd_kcontrol *kcontrol,
303		      struct snd_ctl_elem_value *ucontrol)
304{
305	struct link_master *master = snd_kcontrol_chip(kcontrol);
306	int err = master_init(master);
307	if (err < 0)
308		return err;
309	ucontrol->value.integer.value[0] = master->val;
310	return 0;
311}
312
313static int sync_slaves(struct link_master *master, int old_val, int new_val)
314{
315	struct link_slave *slave;
316	struct snd_ctl_elem_value *uval;
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 = new_val;
326		slave_put_val(slave, uval);
327	}
328	kfree(uval);
329	return 0;
330}
331
332static int master_put(struct snd_kcontrol *kcontrol,
333		      struct snd_ctl_elem_value *ucontrol)
334{
335	struct link_master *master = snd_kcontrol_chip(kcontrol);
336	int err, new_val, old_val;
337	bool first_init;
338
339	err = master_init(master);
340	if (err < 0)
341		return err;
342	first_init = err;
343	old_val = master->val;
344	new_val = ucontrol->value.integer.value[0];
345	if (new_val == old_val)
346		return 0;
347
348	err = sync_slaves(master, old_val, new_val);
349	if (err < 0)
350		return err;
351	if (master->hook && !first_init)
352		master->hook(master->hook_private_data, master->val);
353	return 1;
354}
355
356static void master_free(struct snd_kcontrol *kcontrol)
357{
358	struct link_master *master = snd_kcontrol_chip(kcontrol);
359	struct link_slave *slave, *n;
360
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 */
369		kfree(slave);
370	}
371	kfree(master);
372}
373
374
375/**
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
379 *
380 * Creates a virtual master control with the given name string.
381 *
382 * After creating a vmaster element, you can add the slave controls
383 * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
384 *
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.
389 *
390 * Return: The created control element, or %NULL for errors (ENOMEM).
391 */
392struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
393						 const unsigned int *tlv)
394{
395	struct link_master *master;
396	struct snd_kcontrol *kctl;
397	struct snd_kcontrol_new knew;
398
399	memset(&knew, 0, sizeof(knew));
400	knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
401	knew.name = name;
402	knew.info = master_info;
403
404	master = kzalloc(sizeof(*master), GFP_KERNEL);
405	if (!master)
406		return NULL;
407	INIT_LIST_HEAD(&master->slaves);
408
409	kctl = snd_ctl_new1(&knew, master);
410	if (!kctl) {
411		kfree(master);
412		return NULL;
413	}
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;
419
420	/* additional (constant) TLV read */
421	if (tlv &&
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;
428	}
429
430	return kctl;
431}
432EXPORT_SYMBOL(snd_ctl_make_virtual_master);
433
434/**
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
439 *
440 * Adds the given hook to the vmaster control element so that it's called
441 * at each time when the value is changed.
442 *
443 * Return: Zero.
444 */
445int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
446			     void (*hook)(void *private_data, int),
447			     void *private_data)
448{
449	struct link_master *master = snd_kcontrol_chip(kcontrol);
450	master->hook = hook;
451	master->hook_private_data = private_data;
452	return 0;
453}
454EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
455
456/**
457 * snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
458 * @kcontrol: vmaster kctl element
459 * @hook_only: sync only the hook
460 *
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.
464 */
465void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
466{
467	struct link_master *master;
468	bool first_init = false;
469
470	if (!kcontrol)
471		return;
472	master = snd_kcontrol_chip(kcontrol);
473	if (!hook_only) {
474		int err = master_init(master);
475		if (err < 0)
476			return;
477		first_init = err;
478		err = sync_slaves(master, master->val, master->val);
479		if (err < 0)
480			return;
481	}
482
483	if (master->hook && !first_init)
484		master->hook(master->hook_private_data, master->val);
485}
486EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
487