modbus: document return values of internal functions

};

/**

 * @brief Get Modbus interface context.

 *

 * @param ctx        Modbus interface context

 *

 * @retval           Pointer to interface context or NULL

 *                   if interface not available or not configured;

 */

struct modbus_context *modbus_get_context(const uint8_t iface);

/**

 * @brief Send ADU.

 *

 * @param ctx        Modbus interface context

 */

void modbus_tx_adu(struct modbus_context *ctx);

/**

 * @brief Send ADU and wait certain time for response.

 *

 * @param ctx        Modbus interface context

 *

 * @retval           0 If the function was successful,

 *                   -ENOTSUP if Modbus mode is not supported,

 *                   -ETIMEDOUT on timeout,

 *                   -EMSGSIZE on length error,

 *                   -EIO on CRC error.

 */

int modbus_tx_wait_rx_adu(struct modbus_context *ctx);

/**

 * @brief Let server handle the received ADU.

 *

 * @param ctx        Modbus interface context

 *

 * @retval           True if the server has prepared a response ADU

 *                   that should be sent.

 */

bool modbus_server_handler(struct modbus_context *ctx);

/**

 * @brief Reset server stats.

 *

 * @param ctx        Modbus interface context

 */

void modbus_reset_stats(struct modbus_context *ctx);

/**

 * @brief Disable serial line reception.

 *

 * @param ctx        Modbus interface context

 */

void modbus_serial_rx_disable(struct modbus_context *ctx);

/**

 * @brief Enable serial line reception.

 *

 * @param ctx        Modbus interface context

 */

void modbus_serial_rx_enable(struct modbus_context *ctx);

/**

 * @brief Assemble ADU from serial line RX buffer

 *

 * @param ctx        Modbus interface context

 *

 * @retval           0 If the function was successful,

 *                   -ENOTSUP if serial line mode is not supported,

 *                   -EMSGSIZE on length error,

 *                   -EIO on CRC error.

 */

int modbus_serial_rx_adu(struct modbus_context *ctx);

/**

 * @brief Assemble ADU from serial line RX buffer

 *

 * @param ctx        Modbus interface context

 *

 * @retval           0 If the function was successful,

 *                   -ENOTSUP if serial line mode is not supported.

 */

int modbus_serial_tx_adu(struct modbus_context *ctx);

/**

 * @brief Initialize serial line support.

 *

 * @param ctx        Modbus interface context

 * @param baudrate   Baudrate of the serial line

 * @param parity     UART's parity setting:

 *                       UART_CFG_PARITY_NONE,

 *                       UART_CFG_PARITY_EVEN,

 *                       UART_CFG_PARITY_ODD

 * @param ascii_mode Enable ASCII Transfer Mode

 *

 * @retval           0 If the function was successful.

 */

int modbus_serial_init(struct modbus_context *ctx,

		       uint32_t baudrate,

		       enum uart_config_parity parity,

		       const bool ascii_mode);

/**

 * @brief Disable serial line support.

 *

 * @param ctx        Modbus interface context

 */

void modbus_serial_disable(struct modbus_context *ctx);

#endif /* ZEPHYR_INCLUDE_MODBUS_INTERNAL_H_ */