I2C again

[<viper@xxxxxxxxxxx>]

Hi all,
I’m trying to use a Texas Instruments TMP175 temprature sensor on anAT91RM9200 system ( i2c-gpio).
The code (part of it):
//global varsint i2c_handler;
int main( int argc, char *argv[] ) {    int i=0;    int value=0;    int adapter_nr;    int err;    int funcs;    char buf[8];
    //we don't have to initialize the I2C, since it's done by the driver
    //opening the device    printf("Opening /dev/i2c\n");    if ( ( err = ( i2c_handler = open("/dev/i2c-0",O_RDWR) ) ) < 0 ) {        printf("Error opening /dev/i2c-0! Exiting (%d -%s).\n",err,strerror(errno));        exit(1);    }
    // check for req funcs    printf("Getting available IOCTLs\n");    // get funcs list    if((err = ioctl(i2c_handler, I2C_FUNCS, &funcs) < 0)) {        printf( "Error eeprom_open: %s\n", strerror(err));        exit(1);    }    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_BYTE );    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_BYTE );    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_BYTE_DATA );    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_BYTE_DATA );    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_WORD_DATA );    CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_WORD_DATA );
    printf("Setting slave addr to 0x79\n");    if ( ( err = ioctl(i2c_handler,I2C_SLAVE,0x79) ) < 0 ) {        printf("Error setting SLAVE address! Exiting (%d).\n",err);        exit(1);    }
    value = i2c_smbus_read_byte(i2c_handler);    if ( value < 0 )        fprintf( stderr, "Failed to read from I2C device: %m\n" );
    printf("Reading with read\n");    if ( read(i2c_handler,buf,1) != 1 ) {        printf("Error reading byte! (%s)\n",buf);    }
    printf("Reading with i2c_read\n");    if ( ( value = i2c_smbus_read_byte(i2c_handler)) < 0 ) {        printf("Error readiny byte! (%d)\n",value);    }
    printf("Trying direct write!\n");    buf[0] = 0;
    if ( write(i2c_handler,buf,1) != 1 ) {        printf("Error writing byte! (%s)\n",buf);        return -1;    }
The result:root@(none):/mnt/tmp175# ./tmp175Opening /dev/i2cGetting available IOCTLsSetting slave addr to 0x79Failed to read from I2C device: Operation not permittedReading with readError reading byte! (X†)Reading with i2c_readError readiny byte! (-1)Trying direct write!Error writing byte! ()
The ’dmesg’ output, since debug messages are turned on:i2c-adapter i2c-0: ioctl, cmd=0x705, arg=0xbee5fde4i2c-adapter i2c-0: ioctl, cmd=0x703, arg=0x79i2c-adapter i2c-0: ioctl, cmd=0x720, arg=0xbee5fd74i2c-adapter i2c-0: master_xfer[0] R, addr=0x79, len=1i2c-adapter i2c-0: NAK from device addr 0x79 msg #0i2c-dev: i2c-0 reading 1 bytes.i2c-adapter i2c-0: master_xfer[0] R, addr=0x79, len=1i2c-adapter i2c-0: NAK from device addr 0x79 msg #0i2c-adapter i2c-0: ioctl, cmd=0x720, arg=0xbee5fd74i2c-adapter i2c-0: master_xfer[0] R, addr=0x79, len=1i2c-adapter i2c-0: NAK from device addr 0x79 msg #0i2c-dev: i2c-0 writing 1 bytes.i2c-adapter i2c-0: master_xfer[0] W, addr=0x79, len=1i2c-adapter i2c-0: NAK from device addr 0x79 msg #0
What’s wrong? Am I just lame, or it’s something with the device?
Thanks,
                Tamas



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