The i2c shell was introduced just recently and scan was the first command, I had a prototype for write_byte and read_byte back then but never got to complete it, see
You are welcome to take a crack at it 😉
<devel@...> on behalf of Simon Glass <sjg@...>
I don't see a command to read/write from an i2c device, just 'i2c scan'. Am I missing something? If not, I could take a crack at it.