title: I2C tools, i2cdetect and i2cset works perfectly, but i2cget returns 'read failed'
body: <p>I am pretty new to I2C protocol, but I managed to write to my device.  I bought the ADV7630 evaluation board, which is an HDMI switch controlled by I2C.  </p>
  
  <p>I can write to registers using I2c, also i2cDetect works showing all devices.  I also tried to read register contents, but whatever I try to read, I always get 'Read failed'.  Also i2Cdump get all 'XX'.</p>
  
  <p>Whai I read somewhere is bad connection, so I double checked, and soldered connectors, but this does not helped.</p>
  
  <p>My hardware is ADV7630 Evaluation board from Analog Device, and a Raspberry Pi using raspbian latest distro.</p>
  
  <p>Any clue about that would be really appreciated.</p>
  
  <p>Thanks.</p>
  
  <p>Command used:</p>
  
  <pre><code>i2cdetect -y 1
  </code></pre>
  
  <p>I got only 0x74 device (which is normal according to the adv7630 datasheet)</p>
  
  <pre><code>i2cset -y 1 0x58 0xff 0xff  # reset device
  i2cset -y 1 0x58 0x0c 0x40  # disable chip powerdown
  i2cset -y 1 0x58 0xea 0xc8  # set TXB main map address
  i2cset -y 1 0x58 0xeb 0x80  # set TXB packet map address
  i2cset -y 1 0x58 0xec 0x8e  # set TXB EDID map address
  i2cset -y 1 0x58 0xed 0x8c  # set TXB Test map address
  i2cset -y 1 0x58 0xee 0xb8  # set TXA main map address 
  i2cset -y 1 0x58 0xef 0x70  # set TXA packet map address
  i2cset -y 1 0x58 0xf0 0x7e  # set TXA EDID map address
  i2cset -y 1 0x58 0xf1 0x7a  # set TXA test map address
  i2cset -y 1 0x58 0xf9 0x64  # set repeater map address
  i2cset -y 1 0x58 0xfa 0x6c  # set EDID map address
  i2cset -y 1 0x58 0xfb 0x68  # set HDMI rx map address
  
  
  i2cget -y 1 0x58 0xe1
  </code></pre>
  
  <p>Error: Read failed</p>
  
  <pre><code>i2cdetect -y 1
  </code></pre>
  
  <p>I got devices numbers detected:  (in this case: 38,3d,3f,40,46,47,64,74) which is expected.</p>