I tried to use '*mknod* /dev/i2c-*0 c 89 0' and then tried to use the device. but still when I try to use device it gives IO error (so I concluded, I created incorrect device)*
On Mon, Apr 22, 2013 at 7:41 PM, anish singh <[email protected]>wrote: > does I2c-stub create the /dev node?If it is not creating then you > have to do it yourself. > > > On Mon, Apr 22, 2013 at 5:11 PM, Sagar Padhye <[email protected]> wrote: > >> Hi, >> >> [USING : Ubuntu 12.04 LTS] >> >> I am trying to learn I2C subsystem. I havent found much of well >> documented things that can help a newbie on google. I just chose to read >> the linux kernel documentation txts. >> >> I read the way kernel can interact with i2c through both SMBus calls & >> raw file op calls (ioctl, read, write). It looks good till that point. >> >> The doc also tells about i2c stub. which can be used as follows: >> 1. load the i2c module >> 2. use i2cset (from the i2c-tools project) to pre-load some data >> 3. load the target chip driver module >> 4. observe its behavior in the kernel log >> >> I was able to achieve just the 1st step here. I loaded the module >> successfully. >> $ sudo modprobe i2c-stub chip_addr=0x023 >> >> I got following Kern msg >> $dmesg >> ... >> [658.071706] i2c-stub: Virtual chip at 0x23 >> >> So I believe that step 1 is clear. >> >> in second step I have no idea how to provide needed inputs to command >> -> >> Usage : i2cset [-f] [-y] [-m mask] I2CBUS CHIP-ADDRESS DATA-ADDRESS >> [VALUE] [MODE] >> I tried to give I2CBUS = 0, Chip addr = 0x23 & data addr=0 but it gives >> error >> Error : Could not open file '/dev/i2c-0' or '/dev/i2c/0' : No such file >> or directory >> >> There is no file at all created in /dev corrosponding to this device. >> >> Any idea how to use i2c properly? Is this an ubuntu only problem? Can >> anybody provide a good tutorial like thing to learn about i2c kernel & >> userspace driver programming? >> >> -- >> Thanks and Regards, >> Sagar >> >> _______________________________________________ >> Kernelnewbies mailing list >> [email protected] >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> >> > > _______________________________________________ > Kernelnewbies mailing list > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Thanks and Regards, Sagar
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