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123 lines
2.9 KiB
123 lines
2.9 KiB
/*
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* wiringPiI2C.c:
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* Simplified I2C access routines
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* Copyright (c) 2013 Gordon Henderson
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***********************************************************************
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* This file is part of wiringPi:
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* https://projects.drogon.net/raspberry-pi/wiringpi/
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*
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* wiringPi is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* wiringPi is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with wiringPi.
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* If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <linux/i2c-dev.h>
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#include "wiringPi.h"
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#include "wiringPiI2C.h"
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/*
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* wiringPiI2CRead:
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* Simple device read
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*********************************************************************************
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*/
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int wiringPiI2CRead (int fd)
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{
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return i2c_smbus_read_byte (fd) ;
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}
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/*
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* wiringPiI2CReadReg8: wiringPiI2CReadReg16:
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* Read an 8 or 16-bit value from a regsiter on the device
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*********************************************************************************
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*/
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int wiringPiI2CReadReg8 (int fd, int reg)
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{
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return i2c_smbus_read_byte_data (fd, reg) ;
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}
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int wiringPiI2CReadReg16 (int fd, int reg)
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{
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return i2c_smbus_read_word_data (fd, reg) ;
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}
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/*
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* wiringPiI2CWrite:
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* Simple device write
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*********************************************************************************
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*/
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int wiringPiI2CWrite (int fd, int data)
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{
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return i2c_smbus_write_byte (fd, data) ;
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}
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/*
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* wiringPiI2CWriteReg8: wiringPiI2CWriteReg16:
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* Write an 8 or 16-bit value to the given register
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*********************************************************************************
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*/
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int wiringPiI2CWriteReg8 (int fd, int reg, int data)
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{
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return i2c_smbus_write_byte_data (fd, reg, data) ;
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}
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int wiringPiI2CWriteReg16 (int fd, int reg, int data)
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{
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return i2c_smbus_write_word_data (fd, reg, data) ;
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}
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/*
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* wiringPiI2CSetup:
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* Open the I2C device, and regsiter the target device
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*********************************************************************************
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*/
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int wiringPiI2CSetup (int devId)
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{
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int rev, fd ;
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char *device ;
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if ((rev = piBoardRev ()) < 0)
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{
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fprintf (stderr, "wiringPiI2CSetup: Unable to determine Pi board revision\n") ;
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exit (1) ;
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}
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if (rev == 1)
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device = "/dev/i2c-0" ;
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else
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device = "/dev/i2c-1" ;
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if ((fd = open (device, O_RDWR)) < 0)
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return -1 ;
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if (ioctl (fd, I2C_SLAVE, devId) < 0)
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return -1 ;
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return fd ;
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}
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