title: I2C gives I/O- Errors and EEPROM only gives 0x00
body: <p>I got some troubles with my <strong>Pi Zero W (Stretch)</strong> and my <strong>SparkFun AS7265x</strong> Sensor(<a href="https://cdn.sparkfun.com/assets/c/2/9/0" rel="nofollow noreferrer">https://cdn.sparkfun.com/assets/c/2/9/0</a> ... asheet.pdf):
  I connected them over my GPIOs and created an <strong>I2C Bus</strong>:</p>
  
  <ul>
  <li>I detected my <strong>sensor at 0x49</strong> via "i2cdetect -y 1" </li>
  <li>I configured my rapsi-config (enable i2c)</li>
  <li>I installed the <strong>drivers i2c-tools</strong>, used the <strong>mods i2c-dev and i2c-bcm2708</strong> and edited to my boot/config.txt additionally "dtoverlay=i2c1-bcm2708" and put pi to group i2c for no carrying any longer a sudo with myself.....</li>
  </ul>
  
  <p>--> Now I want to read out some registers e.g. the temperature (0x06) but <strong>everything I get is a 0x00</strong> ("i2cget -y 1 0x49 0x06 b")
  --> The only register I can read is 0x00 and there I get 0x80 (but             default should be 0x40)</p>
  
  <p>so I tried pyserial, but when I want to use: serial.Serial("/dev/i2c-1", 115200) --> I get a <strong>cannot configure port error 25</strong> 
  if I write cat /dev/i2c-1 (as explained in some stack overflow topics) I get an <strong>I/O-Error</strong>..... </p>
  
  <p>I am pretty keyless now.... Maybe there is a clock stretching, but none is mentioned in the data sheet ??</p>
  
  <p>Would be likely if anybody could help me :)</p>
  
  <p>Cheers!</p>
  
  <pre><code>raise SerialException("Could not configure port: {}".format(msg)) 
   serial.serialutil.SerialException: Could not configure port: (25, 'Inappropriate ioctl for device')
  </code></pre>