path: root/include/alsa/control_external.h

/**
 * \file include/control_external.h
 * \brief External control plugin SDK
 * \author Takashi Iwai <tiwai@suse.de>
 * \date 2005
 *
 * External control plugin SDK.
 */

/*
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as
 *   published by the Free Software Foundation; either version 2.1 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
#ifndef __ALSA_CONTROL_EXTERNAL_H
#define __ALSA_CONTROL_EXTERNAL_H

#include "control.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 *  \defgroup CtlPlugin_SDK External Control Plugin SDK
 *  \{
 */

/**
 * Define the object entry for external control plugins
 */
#define SND_CTL_PLUGIN_ENTRY(name) _snd_ctl_##name##_open

/**
 * Define the symbols of the given control plugin with versions
 */
#define SND_CTL_PLUGIN_SYMBOL(name) SND_DLSYM_BUILD_VERSION(SND_CTL_PLUGIN_ENTRY(name), SND_CONTROL_DLSYM_VERSION);

/**
 * Define the control plugin
 */
#define SND_CTL_PLUGIN_DEFINE_FUNC(plugin) \
int SND_CTL_PLUGIN_ENTRY(plugin) (snd_ctl_t **handlep, const char *name,\
                                  snd_config_t *root, snd_config_t *conf, int mode)

/** External control plugin handle */
typedef struct snd_ctl_ext snd_ctl_ext_t;
/** Callback table of control ext */
typedef struct snd_ctl_ext_callback snd_ctl_ext_callback_t;
/** Key to access a control pointer */
typedef unsigned long snd_ctl_ext_key_t;
#ifdef DOC_HIDDEN
/* redefine typedef's for stupid doxygen */
typedef snd_ctl_ext snd_ctl_ext_t;
typedef snd_ctl_ext_callback snd_ctl_ext_callback_t;
#endif
/** Callback to handle TLV commands. */
typedef int (snd_ctl_ext_tlv_rw_t)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int op_flag, unsigned int numid,
                                   unsigned int *tlv, unsigned int tlv_size);

/*
 * Protocol version
 */
#define SND_CTL_EXT_VERSION_MAJOR       1       /**< Protocol major version */
#define SND_CTL_EXT_VERSION_MINOR       0       /**< Protocol minor version */
#define SND_CTL_EXT_VERSION_TINY        1       /**< Protocol tiny version */
/**
 * external plugin protocol version
 */
#define SND_CTL_EXT_VERSION             ((SND_CTL_EXT_VERSION_MAJOR<<16) |\
                                         (SND_CTL_EXT_VERSION_MINOR<<8) |\
                                         (SND_CTL_EXT_VERSION_TINY))

/** Handle of control ext */
struct snd_ctl_ext {
        /**
         * protocol version; #SND_CTL_EXT_VERSION must be filled here
         * before calling #snd_ctl_ext_create()
         */
        unsigned int version;
        /**
         * Index of this card; must be filled before calling #snd_ctl_ext_create()
         */
        int card_idx;
        /**
         * ID string of this card; must be filled before calling #snd_ctl_ext_create()
         */
        char id[16];
        /**
         * Driver name of this card; must be filled before calling #snd_ctl_ext_create()
         */
        char driver[16];
        /**
         * short name of this card; must be filled before calling #snd_ctl_ext_create()
         */
        char name[32];
        /**
         * Long name of this card; must be filled before calling #snd_ctl_ext_create()
         */
        char longname[80];
        /**
         * Mixer name of this card; must be filled before calling #snd_ctl_ext_create()
         */
        char mixername[80];
        /**
         * poll descriptor
         */
        int poll_fd;

        /**
         * callbacks of this plugin; must be filled before calling #snd_pcm_ioplug_create()
         */
        const snd_ctl_ext_callback_t *callback;
        /**
         * private data, which can be used freely in the driver callbacks
         */
        void *private_data;
        /**
         * control handle filled by #snd_ctl_ext_create()
         */
        snd_ctl_t *handle;

        int nonblock;                   /**< non-block mode; read-only */
        int subscribed;                 /**< events subscribed; read-only */

        /**
         * optional TLV data for the control (since protocol 1.0.1)
         */
        union {
                snd_ctl_ext_tlv_rw_t *c;
                const unsigned int *p;
        } tlv;
};

/** Callback table of ext. */
struct snd_ctl_ext_callback {
        /**
         * close the control handle; optional
         */
        void (*close)(snd_ctl_ext_t *ext);
        /**
         * return the total number of elements; required
         */
        int (*elem_count)(snd_ctl_ext_t *ext);
        /**
         * return the element id of the given offset (array index); required
         */
        int (*elem_list)(snd_ctl_ext_t *ext, unsigned int offset, snd_ctl_elem_id_t *id);
        /**
         * convert the element id to a search key; required
         */
        snd_ctl_ext_key_t (*find_elem)(snd_ctl_ext_t *ext, const snd_ctl_elem_id_t *id);
        /**
         * the destructor of the key; optional
         */
        void (*free_key)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key);
        /**
         * get the attribute of the element; required
         */
        int (*get_attribute)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
                             int *type, unsigned int *acc, unsigned int *count);
        /**
         * get the element information of integer type
         */
        int (*get_integer_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
                                long *imin, long *imax, long *istep);
        /**
         * get the element information of integer64 type
         */
        int (*get_integer64_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
                                  int64_t *imin, int64_t *imax, int64_t *istep);
        /**
         * get the element information of enumerated type
         */
        int (*get_enumerated_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items);
        /**
         * get the name of the enumerated item
         */
        int (*get_enumerated_name)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int item,
                                   char *name, size_t name_max_len);
        /**
         * read the current values of integer type
         */
        int (*read_integer)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value);
        /**
         * read the current values of integer64 type
         */
        int (*read_integer64)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int64_t *value);
        /**
         * read the current values of enumerated type
         */
        int (*read_enumerated)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items);
        /**
         * read the current values of bytes type
         */
        int (*read_bytes)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned char *data,
                          size_t max_bytes);
        /**
         * read the current values of iec958 type
         */
        int (*read_iec958)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, snd_aes_iec958_t *iec958);
        /**
         * update the current values of integer type with the given values
         */
        int (*write_integer)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value);
        /**
         * update the current values of integer64 type with the given values
         */
        int (*write_integer64)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int64_t *value);
        /**
         * update the current values of enumerated type with the given values
         */
        int (*write_enumerated)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items);
        /**
         * update the current values of bytes type with the given values
         */
        int (*write_bytes)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned char *data,
                           size_t max_bytes);
        /**
         * update the current values of iec958 type with the given values
         */
        int (*write_iec958)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, snd_aes_iec958_t *iec958);
        /**
         * subscribe/unsubscribe the event notification; optional
         */
        void (*subscribe_events)(snd_ctl_ext_t *ext, int subscribe);
        /**
         * read a pending notification event; optional
         */
        int (*read_event)(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id, unsigned int *event_mask);
        /**
         * return the number of poll descriptors; optional
         */
        int (*poll_descriptors_count)(snd_ctl_ext_t *ext);
        /**
         * fill the poll descriptors; optional
         */
        int (*poll_descriptors)(snd_ctl_ext_t *ext, struct pollfd *pfds, unsigned int space);
        /**
         * mangle the revents of poll descriptors
         */
        int (*poll_revents)(snd_ctl_ext_t *ext, struct pollfd *pfds, unsigned int nfds, unsigned short *revents);
};

/**
 * The access type bits stored in get_attribute callback
 */
typedef enum snd_ctl_ext_access {
        SND_CTL_EXT_ACCESS_READ = (1<<0),
        SND_CTL_EXT_ACCESS_WRITE = (1<<1),
        SND_CTL_EXT_ACCESS_READWRITE = (3<<0),
        SND_CTL_EXT_ACCESS_VOLATILE = (1<<2),
        SND_CTL_EXT_ACCESS_TLV_READ = (1<<4),
        SND_CTL_EXT_ACCESS_TLV_WRITE = (1<<5),
        SND_CTL_EXT_ACCESS_TLV_READWRITE = (3<<4),
        SND_CTL_EXT_ACCESS_TLV_COMMAND = (1<<6),
        SND_CTL_EXT_ACCESS_INACTIVE = (1<<8),
        SND_CTL_EXT_ACCESS_TLV_CALLBACK = (1<<28),
} snd_ctl_ext_access_t;

/**
 * find_elem callback returns this if no matching control element is found
 */
#define SND_CTL_EXT_KEY_NOT_FOUND       (snd_ctl_ext_key_t)(-1)

int snd_ctl_ext_create(snd_ctl_ext_t *ext, const char *name, int mode);
int snd_ctl_ext_delete(snd_ctl_ext_t *ext);

/** \} */

#ifdef __cplusplus
}
#endif

#endif /* __ALSA_CONTROL_EXTERNAL_H */