> My suggestion is to not touch i2c-elektor at all for now, and remove
> the 'clock' parameter from the first iteration of i2c-icy. It can be
> added back in case someone complains, which I deem unlikely.

Full ack.

>   When the PCF8584 is addressed as slave, this register
>   must be loaded with the 7-bit I 2 C-bus address to which the
>   PCF8584 is to respond. During initialization, the own
>   address register S0' must be written to, regardless
>   whether it is later used.

I see. It must be written a non-zero value to leave the monitor mode.
But this really needs no callback, we can hardcode any non-zero value.
If slave support is (ever) to be implemented, the own address will come
from the I2C core.

> Okay, so we don't care. Cool, then it's safe to kick the 'clock'
> parameter from i2c-icy. All 2019 boards (which should be the vast
> majority in existence) came with a 12 MHz oscillator AFAIK, so the
> default should be good.

Most drivers don't allow users to change the bus speed, so I think it is
safe to remove.