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 */
30 struct 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 
41 struct 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 
60 struct 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 
84 static inline struct g_audio *func_to_g_audio(struct usb_function *f)
85 {
86 	return container_of(f, struct g_audio, func);
87 }
88 
89 static 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  */
114 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
115 					const char *card_name);
116 void g_audio_cleanup(struct g_audio *g_audio);
117 
118 int u_audio_start_capture(struct g_audio *g_audio);
119 void u_audio_stop_capture(struct g_audio *g_audio);
120 int u_audio_start_playback(struct g_audio *g_audio);
121 void u_audio_stop_playback(struct g_audio *g_audio);
122 
123 int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val);
124 int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate);
125 int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val);
126 int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate);
127 
128 int u_audio_get_volume(struct g_audio *g_audio, int playback, s16 *val);
129 int u_audio_set_volume(struct g_audio *g_audio, int playback, s16 val);
130 int u_audio_get_mute(struct g_audio *g_audio, int playback, int *val);
131 int u_audio_set_mute(struct g_audio *g_audio, int playback, int val);
132 
133 void u_audio_suspend(struct g_audio *g_audio);
134 
135 #endif /* __U_AUDIO_H */
136