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
14 /*
15 * Same maximum frequency deviation on the slower side as in
16 * sound/usb/endpoint.c. Value is expressed in per-mil deviation.
17 * The maximum deviation on the faster side will be provided as
18 * parameter, as it impacts the endpoint required bandwidth.
19 */
20 #define FBACK_SLOW_MAX 250
21
22 /* Feature Unit parameters */
23 struct uac_fu_params {
24 int id; /* Feature Unit ID */
25
26 bool mute_present; /* mute control enable */
27
28 bool volume_present; /* volume control enable */
29 s16 volume_min; /* min volume in 1/256 dB */
30 s16 volume_max; /* max volume in 1/256 dB */
31 s16 volume_res; /* volume resolution in 1/256 dB */
32 };
33
34 struct uac_params {
35 /* playback */
36 int p_chmask; /* channel mask */
37 int p_srate; /* rate in Hz */
38 int p_ssize; /* sample size */
39 struct uac_fu_params p_fu; /* Feature Unit parameters */
40
41 /* capture */
42 int c_chmask; /* channel mask */
43 int c_srate; /* rate in Hz */
44 int c_ssize; /* sample size */
45 struct uac_fu_params c_fu; /* Feature Unit parameters */
46
47 int req_number; /* number of preallocated requests */
48 int fb_max; /* upper frequency drift feedback limit per-mil */
49 };
50
51 struct g_audio {
52 struct usb_function func;
53 struct usb_gadget *gadget;
54
55 struct usb_ep *in_ep;
56
57 struct usb_ep *out_ep;
58 /* feedback IN endpoint corresponding to out_ep */
59 struct usb_ep *in_ep_fback;
60
61 /* Max packet size for all in_ep possible speeds */
62 unsigned int in_ep_maxpsize;
63 /* Max packet size for all out_ep possible speeds */
64 unsigned int out_ep_maxpsize;
65
66 /* Notify UAC driver about control change */
67 int (*notify)(struct g_audio *g_audio, int unit_id, int cs);
68
69 /* The ALSA Sound Card it represents on the USB-Client side */
70 struct snd_uac_chip *uac;
71
72 struct uac_params params;
73 };
74
func_to_g_audio(struct usb_function * f)75 static inline struct g_audio *func_to_g_audio(struct usb_function *f)
76 {
77 return container_of(f, struct g_audio, func);
78 }
79
num_channels(uint chanmask)80 static inline uint num_channels(uint chanmask)
81 {
82 uint num = 0;
83
84 while (chanmask) {
85 num += (chanmask & 1);
86 chanmask >>= 1;
87 }
88
89 return num;
90 }
91
92 /*
93 * g_audio_setup - initialize one virtual ALSA sound card
94 * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize
95 * @pcm_name: the id string for a PCM instance of this sound card
96 * @card_name: name of this soundcard
97 *
98 * This sets up the single virtual ALSA sound card that may be exported by a
99 * gadget driver using this framework.
100 *
101 * Context: may sleep
102 *
103 * Returns zero on success, or a negative error on failure.
104 */
105 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
106 const char *card_name);
107 void g_audio_cleanup(struct g_audio *g_audio);
108
109 int u_audio_start_capture(struct g_audio *g_audio);
110 void u_audio_stop_capture(struct g_audio *g_audio);
111 int u_audio_start_playback(struct g_audio *g_audio);
112 void u_audio_stop_playback(struct g_audio *g_audio);
113
114 int u_audio_get_volume(struct g_audio *g_audio, int playback, s16 *val);
115 int u_audio_set_volume(struct g_audio *g_audio, int playback, s16 val);
116 int u_audio_get_mute(struct g_audio *g_audio, int playback, int *val);
117 int u_audio_set_mute(struct g_audio *g_audio, int playback, int val);
118
119 #endif /* __U_AUDIO_H */
120