Why do I get an error message: 'Inappropriate ioctl for device' with I2C connection?

Question

I am trying to connect a particle sensor to RPi via I2C.

I have added dtparam=i2c_arm=on to the config.txt file and I have also un-blacklisted I2C.

Using the Serial Python module, I have a script that defines a connection with /dev/i2c-0 and when I try and run this script in the Linux terminal, I get this message:

Traceback (most recent call last):
  File "fly_modt.py", line 23, in <module>
    ser2 = serial.Serial('/dev/i2c-0')
  File "/home/pi/OPC/serial/serialutil.py", line 282, in __init__
    self.open()
  File "/home/pi/OPC/serial/serialposix.py", line 296, in open
    self._reconfigurePort()
  File "/home/pi/OPC/serial/serialposix.py", line 325, in _reconfigurePort
    raise SerialException("Could not configure port: %s" % msg)
serial.serialutil.SerialException: Could not configure port: (25, 'Inappropriate ioctl for device')

I am wondering what is going on and what I need to do in order to get this I2C connection to work.

Also, to add more information to the question, when I use the cat command for i2c-0, I get an Input/ouput error:

cat i2c-0
cat: i2c-0: Input/output error

Thanks

Answer 1

The script is trying to manipulate /dev/i2c-0 (an I2C bus) as if it is a serial link. An I2C bus is not a serial link.

To talk to as I2C bus use the Python SMBus module (or my pigpio's inbuilt I2C support).