[SOLVED] i2c-1 device exist but cant open\ no such file or directory

I have a little problem about my app.

Firstly I install package i2c-tools,
I give all permission to all user for dev/i2c* files.
After, add the line i2c-dev in etc/modules file
i2c devices are exist in /dev/ directory.

I guess problem is in my C code:

int fd = open("/dev/i2c-1", O_RDWR);

returns -1 value and it give errno:2 No such file or directory.

Anyone has a suggestions, whats the problem I couldnt found?
Below i2cdetect, device and permission output.

root@arge16-HP-600B:/home/arge1-6# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- 37 -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- 49 -- -- -- -- -- -- 
50: 50 -- -- -- -- -- -- -- -- 59 -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

root@arge16-HP-600B:/home/arge1-6# i2cdetect -l
i2c-0   i2c         i915 gmbus ssc                      I2C adapter
i2c-1   i2c         i915 gmbus vga                      I2C adapter
i2c-2   i2c         i915 gmbus panel                    I2C adapter
i2c-3   i2c         i915 gmbus dpc                      I2C adapter
i2c-4   i2c         i915 gmbus dpb                      I2C adapter
i2c-5   i2c         i915 gmbus dpd                      I2C adapter
i2c-6   i2c         DPDDC-B

I2C adapter

root@arge16-HP-600B:/home/arge1-6# ls -l /dev/i2c*
crw-rw-rw- 1 root i2c 89, 0 Oct  2 14:36 /dev/i2c-0
crw-rw-rw- 1 root i2c 89, 1 Oct  2 14:36 /dev/i2c-1
crw-rw-rw- 1 root i2c 89, 2 Oct  2 14:36 /dev/i2c-2
crw-rw-rw- 1 root i2c 89, 3 Oct  2 14:36 /dev/i2c-3
crw-rw-rw- 1 root i2c 89, 4 Oct  2 14:36 /dev/i2c-4
crw-rw-rw- 1 root i2c 89, 5 Oct  2 14:36 /dev/i2c-5
crw-rw-rw- 1 root i2c 89, 6 Oct  2 14:36 /dev/i2c-6

You seem to have a module picking up the hardware. This may be an ignorant question, but have you one for a protocol to talk down that hardware. Do the other ones work?

business_kid I try other no changes there/ No such file or directory.
I asked for this issue in many forums I couldnt get any solution

I try other

int fd = open("/dev/i2c-1", O_RDWR);
int fd = open("/dev/i2c-2", O_RDWR);
int fd = open("/dev/i2c-3", O_RDWR);

I get

errno:2 No such file or directory

but I have this device.

What protocol are you talking? If you take a look in your kernel's Documentation/i2c, you will see documents on protocols and clients. Have a look there. The protocol is the file format or language that the cl;ient speaks.

As we are on i2c, some obvious questions: Is port 1 on the same bank as the others. What about i2c-0? Does it need initialization. What makes it different from the others?

Originally Posted by ylmzekrm business_kid I try other no changes there/ No such file or directory. I asked for this issue in many forums I couldnt get any solution I try other int fd = open("/dev/i2c-1", O_RDWR); int fd = open("/dev/i2c-2", O_RDWR); int fd = open("/dev/i2c-3", O_RDWR); I get errno:2 No such file or directory but I have this device.

That's exactly how to do it. I'm sure you've looked after recommendations for I2C Linux source examples. Running this as root? If those devices exist in the system, those open calls should work. I guess also make sure that no other resources are using them, but honestly I'd expect you to get an EACCESS error. I sort of wish that strerror() would also give you the name of the type define symbol versus the string, because I always have to look and find errno.h to validate that it maps to E{whatever}, so my added suggestion is to make sure that 2 does in your system and compile case correspond to the "no such file or directory". That would seem to be ENOENT as called out by the manpage for open(2), but if you look at possible errors from that function, it is highly varied.

I also would say that many, many times with such a varied utility function as open(2) I see general complaints like this and they're not general complaints. For what it's worth, you seem to be doing things correctly. See also if you can download some I2C application, even the source for i2cdetect and see if it's doing an open() and how that works, if not that you have to do it all as root.

Thansk for assist friends, i2c-1 device opened, it was about permission and I solved it with your suggestions.