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+/****************************************************************************
+*
+* Copyright (c) 2006 Dave Hylands <dhylands@gmail.com>
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License version 2 as
+* published by the Free Software Foundation.
+*
+* Alternatively, this software may be distributed under the terms of BSD
+* license.
+*
+* See README and COPYING for more details.
+*
+****************************************************************************/
+/**
+*
+* @file i2c-api.c
+*
+* @brief This file contains the implementation for performing I2C operations
+* on the gumstix.
+*
+****************************************************************************/
+
+// ---- Include Files -------------------------------------------------------
+
+#include <string.h>
+#include <errno.h>
+
+#include "i2c.h"
+#include "i2c-dev.h"
+#include "i2c-api.h"
+
+#include "Crc8.h"
+#include "DumpMem.h"
+#include "Log.h"
+
+// ---- Public Variables ----------------------------------------------------
+
+// ---- Private Constants and Types -----------------------------------------
+
+// ---- Private Variables ---------------------------------------------------
+
+static I2C_Addr_t gI2cAddr;
+static int gUseCrc;
+
+// ---- Private Function Prototypes -----------------------------------------
+
+// ---- Functions -----------------------------------------------------------
+
+//***************************************************************************
+/**
+*
+* Sets the I2C address that we'll be communicating with, as well as whether
+* the device uses smbus PEC (CRC).
+*/
+
+void I2cSetSlaveAddress( int i2cDev, I2C_Addr_t i2cAddr, int useCrc )
+{
+ gI2cAddr = i2cAddr;
+ gUseCrc = useCrc;
+
+ LogDebug( "----- I2cSetSlaveAddress i2cAddr:0x%02x useCrc:%d -----\n",
+ i2cAddr, useCrc );
+
+ // Indicate which slave we wish to speak to
+
+ if ( ioctl( i2cDev, I2C_SLAVE, gI2cAddr ) < 0 )
+ {
+ LogError( "I2cSetSlaveAddress: Error trying to set slave address to 0x%02x (%d %s)\n",
+ gI2cAddr, errno, strerror( errno ));
+ }
+
+ // We do the CRC calculation ourself, so we don't need to tell the driver
+ // that we're using it.
+
+#if 0
+ // Indicate that we use PEC (aka CRCs)
+
+ if ( ioctl( i2cDev, I2C_PEC, 1 ) < 0 )
+ {
+ LogError( "I2cSetSlaveAddress: Error trying to set PEC mode\n" );
+ }
+#endif
+
+} // I2cSetSlaveAddress
+
+//***************************************************************************
+/**
+* Transfer data to/from an i2c device.
+*
+* This function implements the equivalent of the smbus functions using
+* I2C_RDWR.
+*
+* The PXA driver doesn't support the smbus transfers.
+*
+* This function can perform the following SMBUS transactions:
+*
+* Write Byte: wrLen == 1, rdLen == 0
+* Read Byte: wrLen == 0, rdLen == 1
+* Write Word: wrLen == 2, rdLen == 0
+* Read Word: wrLen == 0, rdLen == 2
+* Process Call: wrLen == 2, rdLen == 2
+* Write Block: wrLen == 0x80 + numBytes, rdLen == 0
+* Read Block: wrLen == 0, rdLen == 0x80 + numBytes
+* Process Block: wrLen == 0x80 + numBytes, rdLen == 0x80 + numBytes
+*/
+
+int I2cTransfer
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ const void *wrData, ///< Data to write
+ uint8_t wrLen, ///< Number of bytes to write (or in 0x80 for a block write)
+ void *rdData, ///< Place to store data read
+ uint8_t rdLen, ///< Number of bytes to read (or in 0x80 for a block read)
+ uint8_t *bytesReadp ///< Place to store number of bytes read
+)
+{
+ struct i2c_rdwr_ioctl_data rdwr;
+ struct i2c_msg msg[ 2 ];
+ uint8_t wrBuf[ I2C_MAX_DATA_LEN + 3 ]; // +1 for cmd, +1 for len, +1 for CRC
+ uint8_t rdBuf[ I2C_MAX_DATA_LEN + 2 ]; // +1 for len, +1 for CRC
+ uint8_t crc = 0;
+ uint8_t wrBlock = (( wrLen & 0x80 ) != 0 );
+ uint8_t rdBlock = (( rdLen & 0x80 ) != 0 );
+ int rc = 0;
+
+ LogDebug( "----- I2cTransfer: cmd:0x%02x wrLen:0x%02x rdLen:0x%02x wrBlock:%d rdBlock:%d -----\n",
+ cmd, wrLen, rdLen, wrBlock, rdBlock );
+ if ( wrData != NULL )
+ {
+ LogDebug( "----- wrData:0x%08x *wrData:0x%02x -----\n", wrData, *(const uint8_t *)wrData );
+ }
+
+ rdLen &= 0x7f;
+ wrLen &= 0x7f;
+
+ if ( bytesReadp != NULL )
+ {
+ *bytesReadp = 0;
+ }
+
+ if ( wrLen > I2C_MAX_DATA_LEN )
+ {
+ LogError( "I2cTransfer: wrLen too big: %d, max is %d\n",
+ wrLen, I2C_MAX_DATA_LEN );
+ errno = ENOBUFS;
+ return -1;
+ }
+
+ if ( rdLen > I2C_MAX_DATA_LEN )
+ {
+ LogError( "I2cTransfer: rdLen too big: %d, max is %d\n",
+ rdLen, I2C_MAX_DATA_LEN );
+ errno = ENOBUFS;
+ return -1;
+ }
+
+ // Whether we're doing a read or a write, we always send
+ // the command.
+
+ msg[ 0 ].addr = gI2cAddr;
+ msg[ 0 ].flags = 0;
+ msg[ 0 ].len = wrLen + 1 + wrBlock; // +1 for cmd
+ msg[ 0 ].buf = (char *)&wrBuf[ 0 ];
+
+ if ( gUseCrc )
+ {
+ crc = Crc8( 0, gI2cAddr << 1 );
+ crc = Crc8( crc, cmd );
+ }
+
+ wrBuf[ 0 ] = cmd;
+
+ if ( wrLen > 0 )
+ {
+ // We have some data to send down to the device
+
+ if ( wrBlock )
+ {
+ wrBuf[ 1 ] = wrLen;
+ memcpy( &wrBuf[ 2 ], wrData, wrLen );
+ wrLen++; // Add in cmd to the length
+ }
+ else
+ {
+ memcpy( &wrBuf[ 1 ], wrData, wrLen );
+ }
+ if ( gUseCrc )
+ {
+ crc = Crc8Block( crc, &wrBuf[ 1 ], wrLen );
+
+ if ( rdLen == 0 )
+ {
+ // This is a write-only, so we need to send the CRC
+
+ wrBuf[ wrLen + 1 ] = crc;
+ msg[ 0 ].len++;
+ }
+ }
+ }
+
+ if ( gDebug )
+ {
+ Log( "msg[ 0 ].addr = 0x%02x\n", msg[ 0 ].addr );
+ Log( "msg[ 0 ].flags = 0x%04x\n", msg[ 0 ].flags );
+ Log( "msg[ 0 ].len = %d\n", msg[ 0 ].len );
+ DumpMem( "I2cTransfer W", 0, &wrBuf[ 0 ], msg[ 0 ].len );
+ }
+
+ rdwr.msgs = msg;
+ rdwr.nmsgs = 1;
+
+ if ( rdLen > 0 )
+ {
+ // We're expecting some data to come back
+
+ msg[ 1 ].addr = gI2cAddr;
+ msg[ 1 ].flags = I2C_M_RD;
+ msg[ 1 ].len = rdLen + rdBlock + gUseCrc;
+ msg[ 1 ].buf = (char *)&rdBuf[ 0 ];
+
+ rdwr.nmsgs = 2;
+
+ if ( gUseCrc )
+ {
+ crc = Crc8( crc, ( gI2cAddr << 1 ) | 1 );
+ }
+
+ if ( gDebug )
+ {
+ Log( "msg[ 1 ].addr = 0x%02x\n", msg[ 1 ].addr );
+ Log( "msg[ 1 ].flags = 0x%04x\n", msg[ 1 ].flags );
+ Log( "msg[ 1 ].len = %d\n", msg[ 1 ].len );
+ }
+ }
+
+ if ( ioctl( i2cDev, I2C_RDWR, &rdwr ) < 0 )
+ {
+ LogError( "I2cTransfer: ioctl failed: %s (%d)\n", strerror( errno ), errno );
+ return -1;
+ }
+
+ if ( rdLen > 0 )
+ {
+ if ( rdBlock )
+ {
+ if ( rdBuf[ 0 ] > rdLen )
+ {
+ LogError( "I2cTransfer: length is too big: %d max: %d\n", rdBuf[ 0 ], rdLen );
+
+ rc = EMSGSIZE;
+ }
+ else
+ {
+ rdLen = rdBuf[ 0 ];
+ }
+ }
+
+ if ( gUseCrc )
+ {
+ crc = Crc8Block( crc, &rdBuf[ 0 ], rdLen + rdBlock );
+
+ if ( crc != rdBuf[ rdLen + rdBlock ] )
+ {
+ LogError( "I2cTransfer: CRC failed: Rcvd: 0x%02x, expecting: 0x%02x\n",
+ rdBuf[ rdLen + rdBlock ], crc );
+ rc = EBADMSG;
+ }
+ }
+
+ if ( gDebug )
+ {
+ DumpMem( "I2cTransfer R", 0, &rdBuf[ 0 ], msg[ 1 ].len );
+ }
+ memcpy( rdData, &rdBuf[ rdBlock ], rdLen );
+
+ if ( bytesReadp != NULL )
+ {
+ *bytesReadp = rdLen;
+ }
+ }
+ return rc;
+
+} // I2cTransfer
+
+//***************************************************************************
+/**
+* Uses the SMBUS Process-Block protocol to read data from a device.
+*/
+
+int I2cProcessBlock
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ const void *wrData, ///< Data to write
+ uint8_t wrLen, ///< Number of bytes to write
+ void *rdData, ///< Place to store data read
+ uint8_t rdLen, ///< Number of bytes to read
+ uint8_t *bytesReadp ///< Place to store number of bytes read
+)
+{
+ LogDebug( "----- I2cProcessBlock cmd: 0x%02x wrLen:0x%02x rdLen:0x%02x -----\n", cmd, wrLen, rdLen );
+
+ return I2cTransfer( i2cDev, cmd, wrData, 0x80 | wrLen, rdData, 0x80 | rdLen, bytesReadp );
+
+} // I2cProcessBlock
+
+//***************************************************************************
+/**
+* Uses the SMBUS Read-Block protocol to read data from a device.
+*/
+
+int I2cReadBlock
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ void *rdData, ///< Place to store data read
+ uint8_t rdLen, ///< Number of bytes to read
+ uint8_t *bytesReadp ///< Place to store number of bytes read
+)
+{
+ LogDebug( "----- I2cReadBlock cmd: 0x%02x rdLen:0x%02x -----\n", cmd, rdLen );
+
+ return I2cTransfer( i2cDev, cmd, NULL, 0, rdData, 0x80 | rdLen, bytesReadp );
+
+} // I2cReadBlock
+
+//***************************************************************************
+/**
+* Uses the SMBUS Read-Byte protocol to read a byte.
+*/
+
+int I2cReadByte
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ uint8_t *rdByte ///< Place to store byte read
+)
+{
+ LogDebug( "----- I2cReadByte cmd: 0x%02x -----\n", cmd );
+
+ return I2cTransfer( i2cDev, cmd, NULL, 0, rdByte, 1, NULL );
+
+} // I2cReadByte
+
+//***************************************************************************
+/**
+* Reads an array of bytes usinng i2c (not compatible with SMBUS)
+*/
+
+int I2cReadBytes
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ void *rdByte, ///< Place to store bytes read
+ uint8_t rdLen ///< Number of bytes to read
+)
+{
+ LogDebug( "----- I2cReadBytes cmd: 0x%02x rdLen: 0x%02x -----\n", cmd, rdLen );
+
+ return I2cTransfer( i2cDev, cmd, NULL, 0, rdByte, rdLen, NULL );
+
+} // I2cReadBytes
+
+//***************************************************************************
+/**
+* Uses the SMBUS Write-Block protocol to write data from a device.
+*/
+
+int I2cWriteBlock
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ const void *wrData, ///< Data to write
+ uint8_t wrLen ///< Number of bytes to write
+)
+{
+ LogDebug( "----- I2cWriteBlock cmd: 0x%02x wrLen:0x%02x -----\n", cmd, wrLen );
+
+ return I2cTransfer( i2cDev, cmd, wrData, 0x80 | wrLen, NULL, 0, NULL );
+
+} // I2cWriteBlock
+
+//***************************************************************************
+/**
+* Uses the SMBUS Write-Byte protocol to write a byte.
+*/
+
+int I2cWriteByte
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ uint8_t wrByte ///< Byte to write
+)
+{
+ LogDebug( "----- I2cWriteByte cmd: 0x%02x wrByte:0x%02x -----\n", cmd, wrByte );
+ LogDebug( "----- &wrByte = 0x%08x wrByte = 0x%02x -----\n", &wrByte, *&wrByte );
+
+ return I2cTransfer( i2cDev, cmd, &wrByte, 1, NULL, 0, NULL );
+
+} // I2cWriteByte
+
+//***************************************************************************
+/**
+* Writes an array of bytes using i2c (not compatible with SMBUS)
+*/
+
+int I2cWriteBytes
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t cmd, ///< Command to send
+ const void *wrByte, ///< Bytes to write
+ uint8_t wrLen ///< Number of bytes to write
+)
+{
+ LogDebug( "----- I2cWriteBytes cmd: 0x%02x wrLen: 0x%02x -----\n", cmd, wrLen );
+
+ return I2cTransfer( i2cDev, cmd, wrByte, wrLen, NULL, 0, NULL );
+
+} // I2cWriteBytes
+
+//***************************************************************************
+/**
+* Uses the SMBUS Receive-Byte protocol to read a byte.
+*/
+
+int I2cReceiveByte
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t *rdByte ///< Place to store byte read
+)
+{
+ return I2cReceiveBytes( i2cDev, rdByte, 1 );
+
+} // I2cReceiveByte
+
+//***************************************************************************
+/**
+* Uses the SMBUS Receive-Byte protocol to read multiple (or one or zero) bytes.
+*/
+
+int I2cReceiveBytes
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t *rdData, ///< Place to store data read
+ uint8_t rdLen ///< Number of bytes to read
+)
+{
+ struct i2c_rdwr_ioctl_data rdwr;
+ struct i2c_msg msg;
+
+ LogDebug( "----- I2cReceiveBytes -----\n" );
+
+ msg.addr = gI2cAddr;
+ msg.flags = I2C_M_RD;
+ msg.len = rdLen;
+ msg.buf = (char *)rdData;
+
+ rdwr.msgs = &msg;
+ rdwr.nmsgs = 1;
+
+ if ( ioctl( i2cDev, I2C_RDWR, &rdwr ) < 0 )
+ {
+ LogError( "I2cReceiveBytes: ioctl failed: %s (%d)\n", strerror( errno ), errno );
+ return -1;
+ }
+
+ return 0;
+
+} // I2cReceiveBytes
+
+//***************************************************************************
+/**
+* Uses the SMBUS Send-Byte protocol to write a byte.
+*/
+
+int I2cSendByte
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t wrByte ///< Byte to write
+)
+{
+ return I2cSendBytes( i2cDev, &wrByte, 1 );
+
+} // I2cSendByte
+
+//***************************************************************************
+/**
+* Uses the SMBUS Send-Byte protocol to write multiple (or zero or one) bytes.
+*/
+
+int I2cSendBytes
+(
+ int i2cDev, ///< Handle to i2c-dev file
+ uint8_t *wrData, ///< Pointer to data to write
+ uint8_t wrLen ///< NUmber of bytes to write
+)
+{
+ struct i2c_rdwr_ioctl_data rdwr;
+ struct i2c_msg msg;
+
+ LogDebug( "----- I2cSendBytes wrLen = 0x%02x -----\n", wrLen );
+
+ msg.addr = gI2cAddr;
+ msg.flags = 0;
+ msg.len = wrLen;
+ msg.buf = (char *)wrData;
+
+ rdwr.msgs = &msg;
+ rdwr.nmsgs = 1;
+
+ if ( ioctl( i2cDev, I2C_RDWR, &rdwr ) < 0 )
+ {
+ LogError( "I2cSendBytes: ioctl failed: %s (%d)\n", strerror( errno ), errno );
+ return -1;
+ }
+
+ return 0;
+
+} // I2cSendBytes
+
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