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 struct uac_params { 15 /* playback */ 16 int p_chmask; /* channel mask */ 17 int p_srate; /* rate in Hz */ 18 int p_ssize; /* sample size */ 19 20 /* capture */ 21 int c_chmask; /* channel mask */ 22 int c_srate; /* rate in Hz */ 23 int c_ssize; /* sample size */ 24 25 int req_number; /* number of preallocated requests */ 26 }; 27 28 struct g_audio { 29 struct usb_function func; 30 struct usb_gadget *gadget; 31 32 struct usb_ep *in_ep; 33 struct usb_ep *out_ep; 34 35 /* Max packet size for all in_ep possible speeds */ 36 unsigned int in_ep_maxpsize; 37 /* Max packet size for all out_ep possible speeds */ 38 unsigned int out_ep_maxpsize; 39 40 /* The ALSA Sound Card it represents on the USB-Client side */ 41 struct snd_uac_chip *uac; 42 43 struct uac_params params; 44 }; 45 46 static inline struct g_audio *func_to_g_audio(struct usb_function *f) 47 { 48 return container_of(f, struct g_audio, func); 49 } 50 51 static inline uint num_channels(uint chanmask) 52 { 53 uint num = 0; 54 55 while (chanmask) { 56 num += (chanmask & 1); 57 chanmask >>= 1; 58 } 59 60 return num; 61 } 62 63 /* 64 * g_audio_setup - initialize one virtual ALSA sound card 65 * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize 66 * @pcm_name: the id string for a PCM instance of this sound card 67 * @card_name: name of this soundcard 68 * 69 * This sets up the single virtual ALSA sound card that may be exported by a 70 * gadget driver using this framework. 71 * 72 * Context: may sleep 73 * 74 * Returns zero on success, or a negative error on failure. 75 */ 76 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name, 77 const char *card_name); 78 void g_audio_cleanup(struct g_audio *g_audio); 79 80 int u_audio_start_capture(struct g_audio *g_audio); 81 void u_audio_stop_capture(struct g_audio *g_audio); 82 int u_audio_start_playback(struct g_audio *g_audio); 83 void u_audio_stop_playback(struct g_audio *g_audio); 84 85 #endif /* __U_AUDIO_H */ 86