PROCESSOR-SDK-DRA8X-TDA4X: Execution of I2C test using Linux SDK

Hi Massimo,

The TRM mentions i2c controller registers which are programmed by the i2c driver.
The link: http://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/I2C.html

gives i2c debug tools for the slaves which are generally the ones that need a lot of testing.

Say you connect a PMIC on bus 0 of i2c.

i2cdump -fy -y 0x0 pmic_slave_id will give you all the registers of the PMIC on that slave_id.

Similarly i2cset can be used to write the slave pmic's registers.

What exactly are you looking for?

Best Regards,
Keerthy

Thank you for the response.

Following is what I am attempting to do:

From the Technical Reference Manual of the board, I found that there are 10 multi-master I2C controllers available. So what I wanted to do, was to use any one of these to communicate with the EEPROM (read and write some random data).

I found out the list of buses available using the i2cdetect -l command as mentioned on your documentation. However, this did not give me a clear picture as to which of these was already connected to the EEPROM. So, I checked the individual i2c buses, using the command "i2cdetect -y <0-7>" to check the memory allocation for each (For some reason, I am only able to see 8 devices through the Linux Kernel, not 10)

In two cases, I found that there were some devices on certain memory locations:

1. For bus 0, at 0x50, 0x51

2. For bus 2, at 0x50, 0x51 and 0x54

When I cross-verified with the "User's Guide" documentation, I saw that the I2C addresses mentioned for EEPROM were 0x50 0x53 and 0x54, all for WKUP_I2C0, and 0x50 and 0x51 for BOOT EEPROM.

So, am I correct in assuming that I will be able to communicate with the EEPROM using one of these two buses?

Since I wasn't sure, I wrote the following C code, to attempt to write some data to the EEPROM, and read it back.

#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

int main()
{
__u8 reg = 0x00;
__s32 res;
char buf[10];
buf[0] = reg;
buf[1] = 0x43;
//buf[2] = 0x65;
char buf_r[10];

    int file;
    int adapter_nr = 2;
    char filename[20];
    int i;
    
    file = open("/dev/i2c-2", O_RDWR);
    if(file < 0)
    {
        perror ("unopened");
    }

    int addr = 0x50;
    if(ioctl(file, I2C_SLAVE, addr) < 0)
    {
        perror("issue in file");
    }


    if(write(file, buf, 2) != 2)
    {
        perror("unable to write");        
    }

    printf("Data written :");
    for(i = 0; i<2; i++)
    {
               printf("%x ", buf[i]);
    }
    lseek(file, 0, SEEK_SET);
    
    if(read(file, buf_r, 2) != 2)
    {
        perror ("unable to read");
    }
    else
    {    
        printf("\nresponse read: ");
        for(i=0; i<2; i++)
        {
               printf("%x ", buf_r[i]);
        }
        
    }
    printf("\n");
}

When I run the above code, I notice that the data I attempted to write and the data being read are not the same. From what I can understand, it might be because of one of two reasons:

1. The bus I'm using is incorrect, and therefore the address 0x50 is not correct.

2. In order to write the data, I have to alter some of the I2C registered mentioned in the Technical Reference Manual for the TDA4VM. However, this would mean I have to initialize the I2C and do a little low-level programming, as mentioned in this document.

 Is my understanding correct? If so, what can I do to ensure data transfer?

Thank you.

Hi Massimo,

I will get in touch with experts and come back with more comprehensive answer.

I will get back to you by next week. Apologies for the delay.

Best Regards,
Keerthy