/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * u_audio.h -- interface to USB gadget "ALSA sound card" utilities
 *
 * Copyright (C) 2016
 * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
 */

#ifndef __U_AUDIO_H
#define __U_AUDIO_H

#include <linux/usb/composite.h>
#include "uac_common.h"

/*
 * Same maximum frequency deviation on the slower side as in
 * sound/usb/endpoint.c. Value is expressed in per-mil deviation.
 */
#define FBACK_SLOW_MAX  250

/*
 * Maximum frequency deviation on the faster side, default value for UAC1/2.
 * Value is expressed in per-mil deviation.
 * UAC2 provides the value as a parameter as it impacts the endpoint required
 * bandwidth.
 */
#define FBACK_FAST_MAX 5

/* Feature Unit parameters */
struct uac_fu_params {
        int id;                 /* Feature Unit ID */

        bool mute_present;      /* mute control enable */

        bool volume_present;    /* volume control enable */
        s16 volume_min;         /* min volume in 1/256 dB */
        s16 volume_max;         /* max volume in 1/256 dB */
        s16 volume_res;         /* volume resolution in 1/256 dB */
};

struct uac_params {
        /* playback */
        int p_chmask;   /* channel mask */
        int p_srates[UAC_MAX_RATES];    /* available rates in Hz (0 terminated list) */
        int p_ssize;    /* sample size */
        struct uac_fu_params p_fu;      /* Feature Unit parameters */

        /* capture */
        int c_chmask;   /* channel mask */
        int c_srates[UAC_MAX_RATES];    /* available rates in Hz (0 terminated list) */
        int c_ssize;    /* sample size */
        struct uac_fu_params c_fu;      /* Feature Unit parameters */

        /* rates are dynamic, in uac_rtd_params */

        int req_number; /* number of preallocated requests */
        int fb_max;     /* upper frequency drift feedback limit per-mil */
};

struct g_audio {
        struct usb_function func;
        struct usb_gadget *gadget;

        struct usb_ep *in_ep;

        struct usb_ep *out_ep;
        /* feedback IN endpoint corresponding to out_ep */
        struct usb_ep *in_ep_fback;

        /* Max packet size for all in_ep possible speeds */
        unsigned int in_ep_maxpsize;
        /* Max packet size for all out_ep possible speeds */
        unsigned int out_ep_maxpsize;

        /* Notify UAC driver about control change */
        int (*notify)(struct g_audio *g_audio, int unit_id, int cs);

        /* The ALSA Sound Card it represents on the USB-Client side */
        struct snd_uac_chip *uac;

        struct uac_params params;
};

static inline struct g_audio *func_to_g_audio(struct usb_function *f)
{
        return container_of(f, struct g_audio, func);
}

static inline uint num_channels(uint chanmask)
{
        uint num = 0;

        while (chanmask) {
                num += (chanmask & 1);
                chanmask >>= 1;
        }

        return num;
}

/*
 * g_audio_setup - initialize one virtual ALSA sound card
 * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize
 * @pcm_name: the id string for a PCM instance of this sound card
 * @card_name: name of this soundcard
 *
 * This sets up the single virtual ALSA sound card that may be exported by a
 * gadget driver using this framework.
 *
 * Context: may sleep
 *
 * Returns zero on success, or a negative error on failure.
 */
int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
                                        const char *card_name);
void g_audio_cleanup(struct g_audio *g_audio);

int u_audio_start_capture(struct g_audio *g_audio);
void u_audio_stop_capture(struct g_audio *g_audio);
int u_audio_start_playback(struct g_audio *g_audio);
void u_audio_stop_playback(struct g_audio *g_audio);

int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val);
int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate);
int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val);
int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate);

int u_audio_get_volume(struct g_audio *g_audio, int playback, s16 *val);
int u_audio_set_volume(struct g_audio *g_audio, int playback, s16 val);
int u_audio_get_mute(struct g_audio *g_audio, int playback, int *val);
int u_audio_set_mute(struct g_audio *g_audio, int playback, int val);

void u_audio_suspend(struct g_audio *g_audio);

#endif /* __U_AUDIO_H */