zephyr/include/bluetooth/audio/vocs.h

308 lines
10 KiB
C

/*
* Copyright (c) 2020 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_BLUETOOTH_SERVICES_VOCS_H_
#define ZEPHYR_INCLUDE_BLUETOOTH_SERVICES_VOCS_H_
/**
* @brief Volume Offset Control Service (VOCS)
*
* @defgroup bt_gatt_vocs Volume Offset Control Service (VOCS)
*
* @ingroup bluetooth
* @{
*
* The Volume Offset Control Service is a secondary service, and as such should not be used own its
* own, but rather in the context of another (primary) service.
*
* This API implements both the server and client functionality.
* Note that the API abstracts away the change counter in the volume offset control state and will
* automatically handle any changes to that. If out of date, the client implementation will
* autonomously read the change counter value when executing a write request.
*
* [Experimental] Users should note that the APIs can change as a part of ongoing development.
*/
#include <zephyr/types.h>
#ifdef __cplusplus
extern "C" {
#endif
/** Volume Offset Control Service Error codes */
#define BT_VOCS_ERR_INVALID_COUNTER 0x80
#define BT_VOCS_ERR_OP_NOT_SUPPORTED 0x81
#define BT_VOCS_ERR_OUT_OF_RANGE 0x82
#define BT_VOCS_MIN_OFFSET -255
#define BT_VOCS_MAX_OFFSET 255
/** @brief Opaque Volume Offset Control Service instance. */
struct bt_vocs;
/** @brief Structure for initializing a Volume Offset Control Service instance. */
struct bt_vocs_init_param {
/** Audio Location bitmask */
uint32_t location;
/** Boolean to set whether the location is writable by clients */
bool location_writable;
/** Initial volume offset (-255 to 255) */
int16_t offset;
/** Initial audio output description */
char *output_desc;
/** Boolean to set whether the description is writable by clients */
bool desc_writable;
};
/** @brief Structure for discovering a Volume Offset Control Service instance. */
struct bt_vocs_discover_param {
/**
* @brief The start handle of the discovering.
*
* Typically the @p start_handle of a @ref bt_gatt_include.
*/
uint16_t start_handle;
/**
* @brief The end handle of the discovering.
*
* Typically the @p end_handle of a @ref bt_gatt_include.
*/
uint16_t end_handle;
};
/**
* @brief Get a free service instance of Volume Offset Control Service from the pool.
*
* @return Volume Offset Control Service instance in case of success or NULL in case of error.
*/
struct bt_vocs *bt_vocs_free_instance_get(void);
/**
* @brief Get the service declaration attribute.
*
* The first service attribute returned can be included in any other GATT service.
*
* @param vocs Volume Offset Control Service instance.
*
* @return Pointer to the attributes of the service.
*/
void *bt_vocs_svc_decl_get(struct bt_vocs *vocs);
/**
* @brief Initialize the Volume Offset Control Service instance.
*
* @param vocs Volume Offset Control Service instance.
* @param init Volume Offset Control Service initialization structure.
* May be NULL to use default values.
*
* @return 0 if success, errno on failure.
*/
int bt_vocs_init(struct bt_vocs *vocs, const struct bt_vocs_init_param *init);
/**
* @brief Callback function for the offset state.
*
* Called when the value is read, or if the value is changed by either the server or client.
*
* @param conn Connection to peer device, or NULL if local server read.
* @param inst The instance pointer.
* @param err Error value. 0 on success, GATT error on positive value
* or errno on negative value.
* For notifications, this will always be 0.
* @param offset The offset value.
*/
typedef void (*bt_vocs_state_cb_t)(struct bt_conn *conn, struct bt_vocs *inst,
int err, int16_t offset);
/**
* @brief Callback function for setting offset.
*
* @param conn Connection to peer device, or NULL if local server write.
* @param inst The instance pointer.
* @param err Error value. 0 on success, GATT error on positive value
* or errno on negative value.
*/
typedef void (*bt_vocs_set_offset_cb_t)(struct bt_conn *conn, struct bt_vocs *inst, int err);
/**
* @brief Callback function for the location.
*
* Called when the value is read, or if the value is changed by either the server or client.
*
* @param conn Connection to peer device, or NULL if local server read.
* @param inst The instance pointer.
* @param err Error value. 0 on success, GATT error on positive value
* or errno on negative value.
* For notifications, this will always be 0.
* @param location The location value.
*/
typedef void (*bt_vocs_location_cb_t)(struct bt_conn *conn, struct bt_vocs *inst, int err,
uint32_t location);
/**
* @brief Callback function for the description.
*
* Called when the value is read, or if the value is changed by either the server or client.
*
* @param conn Connection to peer device, or NULL if local server read.
* @param inst The instance pointer.
* @param err Error value. 0 on success, GATT error on positive value
* or errno on negative value.
* For notifications, this will always be 0.
* @param description The description as an UTF-8 encoded string.
*/
typedef void (*bt_vocs_description_cb_t)(struct bt_conn *conn, struct bt_vocs *inst, int err,
char *description);
/**
* @brief Callback function for bt_vocs_discover.
*
* This callback will usually be overwritten by the primary service that
* includes the Volume Control Offset Service client.
*
* @param conn Connection to peer device, or NULL if local server read.
* @param inst The instance pointer.
* @param err Error value. 0 on success, GATT error on positive value
* or errno on negative value.
* For notifications, this will always be 0.
*/
typedef void (*bt_vocs_discover_cb_t)(struct bt_conn *conn, struct bt_vocs *inst, int err);
struct bt_vocs_cb {
bt_vocs_state_cb_t state;
bt_vocs_location_cb_t location;
bt_vocs_description_cb_t description;
#if defined(CONFIG_BT_VOCS_CLIENT)
/* Client only */
bt_vocs_discover_cb_t discover;
bt_vocs_set_offset_cb_t set_offset;
#endif /* CONFIG_BT_VOCS_CLIENT */
};
/**
* @brief Read the Volume Offset Control Service offset state.
*
* The value is returned in the bt_vocs_cb.state callback.
*
* @param conn Connection to peer device, or NULL to read local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_state_get(struct bt_conn *conn, struct bt_vocs *inst);
/**
* @brief Set the Volume Offset Control Service offset state.
*
* @param conn Connection to peer device, or NULL to set local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
* @param offset The offset to set (-255 to 255).
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_state_set(struct bt_conn *conn, struct bt_vocs *inst, int16_t offset);
/**
* @brief Read the Volume Offset Control Service location.
*
* The value is returned in the bt_vocs_cb.location callback.
*
* @param conn Connection to peer device, or NULL to read local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_location_get(struct bt_conn *conn, struct bt_vocs *inst);
/**
* @brief Set the Volume Offset Control Service location.
*
* @param conn Connection to peer device, or NULL to read local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
* @param location The location to set.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_location_set(struct bt_conn *conn, struct bt_vocs *inst, uint32_t location);
/**
* @brief Read the Volume Offset Control Service output description.
*
* The value is returned in the bt_vocs_cb.description callback.
*
* @param conn Connection to peer device, or NULL to read local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_description_get(struct bt_conn *conn, struct bt_vocs *inst);
/**
* @brief Set the Volume Offset Control Service description.
*
* @param conn Connection to peer device, or NULL to set local server value.
* @param inst Pointer to the Volume Offset Control Service instance.
* @param description The UTF-8 encoded string description to set.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_description_set(struct bt_conn *conn, struct bt_vocs *inst,
const char *description);
/**
* @brief Register callbacks for the Volume Offset Control Service.
*
* @param inst Pointer to the Volume Offset Control Service instance.
* @param cb Pointer to the callback structure.
*
* @return 0 on success, GATT error value on fail.
*/
int bt_vocs_cb_register(struct bt_vocs *inst, struct bt_vocs_cb *cb);
/**
* @brief Registers the callbacks for the Volume Offset Control Service client.
*
* @param inst Pointer to the Volume Offset Control Service client instance.
* @param cb Pointer to the callback structure.
*/
void bt_vocs_client_cb_register(struct bt_vocs *inst, struct bt_vocs_cb *cb);
/**
* @brief Returns a pointer to a Volume Offset Control Service client instance.
*
* @return Pointer to the instance, or NULL if no free instances are left.
*/
struct bt_vocs *bt_vocs_client_free_instance_get(void);
/**
* @brief Discover a Volume Offset Control Service.
*
* Attempts to discover a Volume Offset Control Service on a server given the @p param.
*
* @param conn Connection to the peer with the Volume Offset Control Service.
* @param inst Pointer to the Volume Offset Control Service client instance.
* @param param Pointer to the parameters.
*
* @return 0 on success, errno on fail.
*/
int bt_vocs_discover(struct bt_conn *conn, struct bt_vocs *inst,
const struct bt_vocs_discover_param *param);
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#endif /* ZEPHYR_INCLUDE_BLUETOOTH_SERVICES_VOCS_H_ */