[Voyage-linux] ALIX.2D2 and I2C EEPROM

[Markus Cords]

Hello John,

1. yes, /dev/i2c-0 exist
2. crw-rw---- 1 root i2c 89, 0 Jan  1  2000 /dev/i2c-0
3. user root is using the Software

lg, markus



Am 02.05.2012 11:15, schrieb John Coltrane:
> Hello Markus,
>
> 1. does /dev/i2c-0 exist ?
> 2. what are it's permissions ?
> 3. has the user you try to run your software permissions to write to
> /dev/i2c-0 ?
>
> cheers, John
>
>
> On 05/01/2012 01:26 PM, Markus Cords wrote:
>> Hello,
>>
>> I have a ALIX 2D2 Board with Voyage 0.8.
>> My Problem is to access the I2C EEPROM (externel) with my programm.
>>
>> root at voyage:/tmp# i2cdetect -y 0
>>       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
>> 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>> 40: -- -- -- -- -- -- -- -- -- -- -- -- UU -- -- --
>> 50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>> 70: -- -- -- -- -- -- -- --
>> root at voyage:/tmp#
>>
>>
>> The Address of the eeprom is 0x50
>>
>>
>> with my programm:
>> root at voyage:/tmp# ./main
>> Failed to write to the i2c bus.
>>
>>
>> [code]
>>
>> #include<errno.h>
>> #include<string.h>
>> #include<stdio.h>
>> #include<stdlib.h>
>> #include<unistd.h>
>> #include<linux/i2c-dev.h>
>> #include<sys/ioctl.h>
>> #include<sys/types.h>
>> #include<sys/stat.h>
>> #include<fcntl.h>
>>
>> void main(void) {
>>    int file;
>>    char *filename = "/dev/i2c-0";
>>    if((file = open(filename, O_RDWR))<  0)
>>    {
>>      perror("Failed to open the i2c bus");
>>      exit(1);
>>    }
>>
>>    int addr = 0x50;
>>    if (ioctl(file, I2C_SLAVE, addr)<  0) {
>>      printf("Failed to acquire bus access and/or talk to slave.\n");
>>      exit(1);
>>    }
>>    char buf[10] = {0};
>>
>>    buf[0] = 0x00;
>>    buf[1] = 0xAA;
>>    if(write(file, buf, 2) != 1)
>>    {
>>      printf("Failed to write to the i2c bus.\n");
>>      printf("\n\n");
>>    }
>> }
>> [/code]
>>
>> I hope anybody can help me.
>>
>> Thanks,
>> Markus
>>
>> _______________________________________________
>> Voyage-linux mailing list
>> Voyage-linux at list.voyage.hk
>> http://list.voyage.hk/mailman/listinfo/voyage-linux
>
> _______________________________________________
> Voyage-linux mailing list
> Voyage-linux at list.voyage.hk
> http://list.voyage.hk/mailman/listinfo/voyage-linux