421 lines
11 KiB
C
421 lines
11 KiB
C
// Library: libi2c API
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// File: smbus.c
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/*! \file
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*
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* $LastChangedDate: 2009-09-09 09:44:12 -0600 (Wed, 09 Sep 2009) $
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* $Rev: 130 $
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*
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* \brief System Management Bus (SMBus) over I<sup>2</sup>C communication
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* interface.
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*
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* \author Robin Knight (robin.knight@roadnarrows.com)
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*
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* \par Copyright:
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* (C) 2009. RoadNarrows LLC.
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* (http://www.roadnarrows.com) \n
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* All Rights Reserved
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*
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* <hr>
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* \par Original Source and Copyright:
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* See i2c-dev.h.
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*
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* <hr>
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*/
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// Permission is hereby granted, without written agreement and without
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// license or royalty fees, to use, copy, modify, and distribute this
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// software and its documentation for any purpose, provided that
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// (1) The above copyright notice and the following two paragraphs
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// appear in all copies of the source code and (2) redistributions
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// including binaries reproduces these notices in the supporting
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// documentation. Substantial modifications to this software may be
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// copyrighted by their authors and need not follow the licensing terms
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// described here, provided that the new terms are clearly indicated in
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// all files where they apply.
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//
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// IN NO EVENT SHALL THE AUTHOR, ROADNARROWS LLC, OR ANY MEMBERS/EMPLOYEES
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// OF ROADNARROW LLC OR DISTRIBUTORS OF THIS SOFTWARE BE LIABLE TO ANY
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// PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
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// DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
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// EVEN IF THE AUTHORS OR ANY OF THE ABOVE PARTIES HAVE BEEN ADVISED OF
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// THE POSSIBILITY OF SUCH DAMAGE.
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//
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// THE AUTHOR AND ROADNARROWS LLC SPECIFICALLY DISCLAIM ANY WARRANTIES,
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// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN
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// "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO
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// PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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//
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////////////////////////////////////////////////////////////////////////////////
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#include "smbus.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*!
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* \brief Execute an SMBus IOCTL.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param read_write Operation access type.
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* \param command Operation command or immediate data.
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* \param size Data size.
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* \param [in,out] data Read/write/control data
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_access(int fd, uint8_t read_write, uint8_t command,
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int size, i2c_smbus_data_t *data)
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{
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i2c_smbus_ioctl_data_t args;
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args.read_write = read_write;
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args.command = command;
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args.size = size;
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args.data = data;
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return ioctl(fd, I2C_SMBUS, &args);
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}
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/*!
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* \brief Write a quick value to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param value Value to write
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_quick(int fd, uint8_t value)
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{
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return i2c_smbus_access(fd, value, I2C_NOCMD, I2C_SMBUS_QUICK, NULL);
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}
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/*!
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* \brief Read an immediate byte from the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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*
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* \return
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* Returns read byte on on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_read_byte(int fd)
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{
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i2c_smbus_data_t data;
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int rc;
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rc = i2c_smbus_access(fd, I2C_SMBUS_READ, I2C_NOCMD, I2C_SMBUS_BYTE, &data);
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return rc>=0? 0x0FF & data.byte: -1;
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}
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/*!
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* \brief Write an immediate byte to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param value Byte value to write.
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_byte(int fd, uint8_t value)
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{
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return i2c_smbus_access(fd, I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
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}
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/*!
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* \brief Read a data byte from the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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*
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* \return
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* Returns read byte on on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_read_byte_data(int fd, uint8_t command)
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{
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i2c_smbus_data_t data;
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int rc;
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rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_BYTE_DATA,
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&data);
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return rc>=0? 0x0FF & data.byte: -1;
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}
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/*!
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* \brief Write a data byte to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param value Byte value to write.
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_byte_data(int fd, uint8_t command, uint8_t value)
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{
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i2c_smbus_data_t data;
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data.byte = value;
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return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
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I2C_SMBUS_BYTE_DATA, &data);
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}
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/*!
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* \brief Read a data 2-byte word from the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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*
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* \return
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* Returns read 2-byte word on on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_read_word_data(int fd, uint8_t command)
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{
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i2c_smbus_data_t data;
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int rc;
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rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_WORD_DATA,
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&data);
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return rc>=0? 0x0FFFF & data.word: -1;
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}
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/*!
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* \brief Write a data 2-byte word to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param value Word value to write.
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_word_data(int fd, uint8_t command, unsigned short value)
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{
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i2c_smbus_data_t data;
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data.word = value;
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return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
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I2C_SMBUS_WORD_DATA, &data);
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}
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/*!
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* \brief Issue a 2-byte word process call (write/read) to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param value Word value to write.
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*
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* \return
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* Returns read 2-byte word on on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_process_call(int fd, uint8_t command, unsigned short value)
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{
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i2c_smbus_data_t data;
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int rc;
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data.word = value;
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rc = i2c_smbus_access(fd, I2C_SMBUS_WRITE, command, I2C_SMBUS_PROC_CALL,
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&data);
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return rc>=0? 0x0FFFF & data.word: -1;
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}
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/*!
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* \brief Read a block of data from the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param [out] values Buffer to hold the block of read byte values.\n
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* Must be large enough to receive the data.
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*
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* \return
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* On success, returns \h_ge 0 the number of bytes read, excluding any header
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* fields. Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_read_block_data(int fd, uint8_t command, uint8_t *values)
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{
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i2c_smbus_data_t data;
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int i;
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int rc;
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rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_BLOCK_DATA,
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&data);
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if( rc >= 0 )
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{
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for(i=1; i<=data.block[0]; ++i)
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{
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values[i-1] = data.block[i];
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}
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rc = data.block[0];
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}
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return rc;
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}
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/*!
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* \brief Write a data block to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param length Length of buffer (bytes) to write.
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* \param [in] values Buffer of data to write.
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_block_data(int fd, uint8_t command, uint8_t length,
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const uint8_t *values)
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{
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i2c_smbus_data_t data;
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int i;
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if( length > I2C_SMBUS_BLOCK_MAX )
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{
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length = I2C_SMBUS_BLOCK_MAX;
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}
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for(i=1; i<=length; i++)
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{
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data.block[i] = values[i-1];
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}
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data.block[0] = length;
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return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
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I2C_SMBUS_BLOCK_DATA, &data);
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}
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/*!
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* \brief Read a block of data from the SMBus via low-level I<sup>2</sup>C.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param [out] values Buffer to hold the block of read byte values.\n
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* Must be large enough to receive the data.
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*
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* \return
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* On success, returns \h_ge 0 the number of bytes read, excluding any header
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* fields. Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_read_i2c_block_data(int fd, uint8_t command, uint8_t *values)
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{
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i2c_smbus_data_t data;
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int i;
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int rc;
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rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_I2C_BLOCK_DATA,
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&data);
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if( rc >= 0 )
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{
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for(i=1; i<=data.block[0]; i++)
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{
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values[i-1] = data.block[i];
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}
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rc = data.block[0];
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}
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return rc;
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}
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/*!
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* \brief Write a block of data to the SMBus via low-level I<sup>2</sup>C.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param length Length of buffer (bytes) to write.
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* \param [in] values Buffer of data to write.
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*
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* \return
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* Returns \h_ge 0 on success.
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* Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_write_i2c_block_data(int fd, uint8_t command, uint8_t length,
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const uint8_t *values)
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{
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i2c_smbus_data_t data;
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int i;
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if( length > I2C_SMBUS_I2C_BLOCK_MAX )
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{
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length = I2C_SMBUS_I2C_BLOCK_MAX;
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}
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for(i=1; i<=length; i++)
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{
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data.block[i] = values[i-1];
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}
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data.block[0] = length;
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return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
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I2C_SMBUS_I2C_BLOCK_DATA, &data);
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}
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/*!
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* \brief Issue a block process call (write/read) to the SMBus.
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*
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* \param fd File descriptor to opened SMBus device.
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* \param command Command to SMBus device.
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* \param length Length of buffer (bytes) to write.
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* \param [in,out] values Buffer of data to write and to hold the block of
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* read byte values.\n
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* Must be large enough to receive the data.
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*
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* \return
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* On success, returns \h_ge 0 the number of bytes read, excluding any header
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* fields. Else errno is set appropriately and -1 is returned.
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*/
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int i2c_smbus_block_process_call(int fd, uint8_t command, uint8_t length,
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uint8_t *values)
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{
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i2c_smbus_data_t data;
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int i;
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int rc;
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if( length > I2C_SMBUS_BLOCK_MAX )
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{
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length = I2C_SMBUS_BLOCK_MAX;
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}
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for(i=1; i<=length; i++)
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{
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data.block[i] = values[i-1];
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}
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data.block[0] = length;
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rc = i2c_smbus_access(fd, I2C_SMBUS_WRITE, command, I2C_SMBUS_BLOCK_PROC_CALL,
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&data);
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if( rc >= 0 )
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{
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for(i=1; i<=data.block[0]; i++)
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{
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values[i-1] = data.block[i];
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}
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rc = data.block[0];
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}
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return rc;
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}
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#ifdef __cplusplus
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}
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#endif
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