1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * u_audio.h -- interface to USB gadget "ALSA sound card" utilities
4 *
5 * Copyright (C) 2016
6 * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
7 */
8
9#ifndef __U_AUDIO_H
10#define __U_AUDIO_H
11
12#include <linux/usb/composite.h>
13#include "uac_common.h"
14
15/*
16 * Same maximum frequency deviation on the slower side as in
17 * sound/usb/endpoint.c. Value is expressed in per-mil deviation.
18 */
19#define FBACK_SLOW_MAX 250
20
21/*
22 * Maximum frequency deviation on the faster side, default value for UAC1/2.
23 * Value is expressed in per-mil deviation.
24 * UAC2 provides the value as a parameter as it impacts the endpoint required
25 * bandwidth.
26 */
27#define FBACK_FAST_MAX 5
28
29/* Feature Unit parameters */
30struct uac_fu_params {
31 int id; /* Feature Unit ID */
32
33 bool mute_present; /* mute control enable */
34
35 bool volume_present; /* volume control enable */
36 s16 volume_min; /* min volume in 1/256 dB */
37 s16 volume_max; /* max volume in 1/256 dB */
38 s16 volume_res; /* volume resolution in 1/256 dB */
39};
40
41struct uac_params {
42 /* playback */
43 int p_chmask; /* channel mask */
44 int p_srates[UAC_MAX_RATES]; /* available rates in Hz (0 terminated list) */
45 int p_ssize; /* sample size */
46 struct uac_fu_params p_fu; /* Feature Unit parameters */
47
48 /* capture */
49 int c_chmask; /* channel mask */
50 int c_srates[UAC_MAX_RATES]; /* available rates in Hz (0 terminated list) */
51 int c_ssize; /* sample size */
52 struct uac_fu_params c_fu; /* Feature Unit parameters */
53
54 /* rates are dynamic, in uac_rtd_params */
55
56 int req_number; /* number of preallocated requests */
57 int fb_max; /* upper frequency drift feedback limit per-mil */
58};
59
60struct g_audio {
61 struct usb_function func;
62 struct usb_gadget *gadget;
63
64 struct usb_ep *in_ep;
65
66 struct usb_ep *out_ep;
67 /* feedback IN endpoint corresponding to out_ep */
68 struct usb_ep *in_ep_fback;
69
70 /* Max packet size for all in_ep possible speeds */
71 unsigned int in_ep_maxpsize;
72 /* Max packet size for all out_ep possible speeds */
73 unsigned int out_ep_maxpsize;
74
75 /* Notify UAC driver about control change */
76 int (*notify)(struct g_audio *g_audio, int unit_id, int cs);
77
78 /* The ALSA Sound Card it represents on the USB-Client side */
79 struct snd_uac_chip *uac;
80
81 struct uac_params params;
82};
83
84static inline struct g_audio *func_to_g_audio(struct usb_function *f)
85{
86 return container_of(f, struct g_audio, func);
87}
88
89static inline uint num_channels(uint chanmask)
90{
91 uint num = 0;
92
93 while (chanmask) {
94 num += (chanmask & 1);
95 chanmask >>= 1;
96 }
97
98 return num;
99}
100
101/*
102 * g_audio_setup - initialize one virtual ALSA sound card
103 * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize
104 * @pcm_name: the id string for a PCM instance of this sound card
105 * @card_name: name of this soundcard
106 *
107 * This sets up the single virtual ALSA sound card that may be exported by a
108 * gadget driver using this framework.
109 *
110 * Context: may sleep
111 *
112 * Returns zero on success, or a negative error on failure.
113 */
114int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
115 const char *card_name);
116void g_audio_cleanup(struct g_audio *g_audio);
117
118int u_audio_start_capture(struct g_audio *g_audio);
119void u_audio_stop_capture(struct g_audio *g_audio);
120int u_audio_start_playback(struct g_audio *g_audio);
121void u_audio_stop_playback(struct g_audio *g_audio);
122
123int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val);
124int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate);
125int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val);
126int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate);
127
128int u_audio_get_volume(struct g_audio *g_audio, int playback, s16 *val);
129int u_audio_set_volume(struct g_audio *g_audio, int playback, s16 val);
130int u_audio_get_mute(struct g_audio *g_audio, int playback, int *val);
131int u_audio_set_mute(struct g_audio *g_audio, int playback, int val);
132
133void u_audio_suspend(struct g_audio *g_audio);
134
135#endif /* __U_AUDIO_H */
136

source code of linux/drivers/usb/gadget/function/u_audio.h