<div dir="ltr">Hi,<div><br></div><div>[USING : Ubuntu 12.04 LTS]</div><div><br><div>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.<br clear="all">
<div><br></div><div style>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.</div><div style><br></div><div style>The doc also tells about i2c stub. which can be used as follows:</div>
<div style><div><span class="" style="white-space:pre"> </span>1. load the i2c module</div><div><span class="" style="white-space:pre"> </span>2. use i2cset (from the i2c-tools project) to pre-load some data</div><div><span class="" style="white-space:pre"> </span>3. load the target chip driver module</div>
<div><span class="" style="white-space:pre"> </span>4. observe its behavior in the kernel log</div><div><br></div><div style>I was able to achieve just the 1st step here. I loaded the module successfully.</div><div style>
$ sudo modprobe i2c-stub chip_addr=0x023</div><div style><br></div><div style>I got following Kern msg</div><div style>$dmesg</div><div style>...</div><div style>[658.071706] i2c-stub: Virtual chip at 0x23</div><div style>
<br></div><div style>So I believe that step 1 is clear.</div><div style><br></div><div style>in second step I have no idea how to provide needed inputs to command</div><div style>-></div><div style>Usage : i2cset [-f] [-y] [-m mask] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] [MODE]</div>
<div style>I tried to give I2CBUS = 0, Chip addr = 0x23 & data addr=0 but it gives error</div><div style>Error : Could not open file '/dev/i2c-0' or '/dev/i2c/0' : No such file or directory</div><div style>
<br></div><div style>There is no file at all created in /dev corrosponding to this device.</div><div style><br></div><div style>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?</div>
<div style><br></div></div>-- <br><div dir="ltr">Thanks and Regards,<div>Sagar</div></div>
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