2011-03-02 10:56:56     i2c-dev Issues

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2011-03-02 10:56:56     i2c-dev Issues

Nathan V (CANADA)

Message: 98597   





I've been trying for days to get i2c-dev working properly. I have everything I need according to instructions, but for some reason I keep getting errors at ioctl.








int file;




//Open i2c dev


if(file = open( "/dev/i2c-0", O_RDWR )<0)




enabled = -1;


printf("Unable to open file /dev/i2c-0.\n");








printf("Opened file /dev/i2c-0.\n");


enabled = 1;





printf("File is %d\n",file);



if( ioctl( file, I2C_SLAVE, 0x4b ) < 0 )




printf("Error opening file: %s\n", strerror( errno ) );


printf("Open chip %d FAILED file %d\n", 0x4b, file);








printf("Open chip %d Succeeded file %d\n",0x4b, file);











At the level of ioctl(file, i2C_SLAVE,address) I get the following error: "Error opening file: Invalid argument". So I'm successfully opening /dev/i2c-0 but I can't do a ioctl to the specific chip address. I've already verified the chip address using i2cdetect, and I've also verified that I can read/write with the other i2ctools suite.


What am I missing?


I am including the i2c-dev.h file from the the i2c-tools package. I just put it in my src directory and I #include "i2c-dev.h" as my final include in my .cpp file. All the defines and functions are configuring correctly, so I imagine it's included right. But I wonder if I need to compile the i2c-dev.h file separately or in a different way than my other code?


I am compiling with -O2 as I understand that's somehow required. Not sure if there needs to be anything else special in my make file since everything is building correctly without errors.







2011-03-02 21:39:18     Re: i2c-dev Issues

Mike Frysinger (UNITED STATES)

Message: 98605   


please dont post the same question multiple times to the forum.  once is enough.