A protocol for interacting with I2C devices directly. Most of the time you'll want to use the Chip protocol for working with registers, but this is provided for consistency's sake.

This API is extremely similar to the Circuits.I2C APIs, except that it takes a Conn which implements I2C as an argument.

Deriving

If you're implementing your own Conn type that simply delegates to one of the lower level drivers then you can derive this protocol automatically:

defstruct MyI2CDevice do
  @derive Wafer.I2C
  defstruct [:conn]
endcopy

If your type uses a key other than conn for the inner connection you can specify it while deriving:

defstruct MyI2CDevice do
  @derive {Wafer.I2C, key: :i2c_conn}
  defstruct [:i2c_conn]
endcopy