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 */ 18 #define FBACK_SLOW_MAX 250 19 20 /* 21 * Maximum frequency deviation on the faster side, default value for UAC1/2. 22 * Value is expressed in per-mil deviation. 23 * UAC2 provides the value as a parameter as it impacts the endpoint required 24 * bandwidth. 25 */ 26 #define FBACK_FAST_MAX 5 27 28 /* Feature Unit parameters */ 29 struct uac_fu_params { 30 int id; /* Feature Unit ID */ 31 32 bool mute_present; /* mute control enable */ 33 34 bool volume_present; /* volume control enable */ 35 s16 volume_min; /* min volume in 1/256 dB */ 36 s16 volume_max; /* max volume in 1/256 dB */ 37 s16 volume_res; /* volume resolution in 1/256 dB */ 38 }; 39 40 struct uac_params { 41 /* playback */ 42 int p_chmask; /* channel mask */ 43 int p_srate; /* rate in Hz */ 44 int p_ssize; /* sample size */ 45 struct uac_fu_params p_fu; /* Feature Unit parameters */ 46 47 /* capture */ 48 int c_chmask; /* channel mask */ 49 int c_srate; /* rate in Hz */ 50 int c_ssize; /* sample size */ 51 struct uac_fu_params c_fu; /* Feature Unit parameters */ 52 53 int req_number; /* number of preallocated requests */ 54 int fb_max; /* upper frequency drift feedback limit per-mil */ 55 }; 56 57 struct g_audio { 58 struct usb_function func; 59 struct usb_gadget *gadget; 60 61 struct usb_ep *in_ep; 62 63 struct usb_ep *out_ep; 64 /* feedback IN endpoint corresponding to out_ep */ 65 struct usb_ep *in_ep_fback; 66 67 /* Max packet size for all in_ep possible speeds */ 68 unsigned int in_ep_maxpsize; 69 /* Max packet size for all out_ep possible speeds */ 70 unsigned int out_ep_maxpsize; 71 72 /* Notify UAC driver about control change */ 73 int (*notify)(struct g_audio *g_audio, int unit_id, int cs); 74 75 /* The ALSA Sound Card it represents on the USB-Client side */ 76 struct snd_uac_chip *uac; 77 78 struct uac_params params; 79 }; 80 81 static inline struct g_audio *func_to_g_audio(struct usb_function *f) 82 { 83 return container_of(f, struct g_audio, func); 84 } 85 86 static inline uint num_channels(uint chanmask) 87 { 88 uint num = 0; 89 90 while (chanmask) { 91 num += (chanmask & 1); 92 chanmask >>= 1; 93 } 94 95 return num; 96 } 97 98 /* 99 * g_audio_setup - initialize one virtual ALSA sound card 100 * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize 101 * @pcm_name: the id string for a PCM instance of this sound card 102 * @card_name: name of this soundcard 103 * 104 * This sets up the single virtual ALSA sound card that may be exported by a 105 * gadget driver using this framework. 106 * 107 * Context: may sleep 108 * 109 * Returns zero on success, or a negative error on failure. 110 */ 111 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name, 112 const char *card_name); 113 void g_audio_cleanup(struct g_audio *g_audio); 114 115 int u_audio_start_capture(struct g_audio *g_audio); 116 void u_audio_stop_capture(struct g_audio *g_audio); 117 int u_audio_start_playback(struct g_audio *g_audio); 118 void u_audio_stop_playback(struct g_audio *g_audio); 119 120 int u_audio_get_volume(struct g_audio *g_audio, int playback, s16 *val); 121 int u_audio_set_volume(struct g_audio *g_audio, int playback, s16 val); 122 int u_audio_get_mute(struct g_audio *g_audio, int playback, int *val); 123 int u_audio_set_mute(struct g_audio *g_audio, int playback, int val); 124 125 #endif /* __U_AUDIO_H */ 126