On 03/20/2018 10:52 AM, Wolfram Sang wrote:

quoted

I do believe the hw can support it, even it looks odd to me having the same I2C
in slave and master mode at the same time.

I2C is multi-master, so it is perfectly valid for a device to be master
and slave. I do have seen designs making use of that more than once.

quoted

Nevertheless the driver is devised to support either master or slave more but
not at the same time.

Why should we limit ourselves here? Also, why should we have an
unnecessary configuration option?

Unless the HW is broken and does not support it, I usually don't accept
slave-only solutions. If the needs for master and slave arises later,
this is hard to refactor and better done properly right away.

Is it so hard? Usually you have irqs for master and for slave seperated,
so you can code things quite orthogonal. Check de20d1857dd6 ("i2c: rcar:
add slave support") as an example.

I need to check at my end but status bits are shared between master and slave in
my IP: i.e. Tx Empty, Rx Empty, NAxk, Stop.
Both bits have a meaning in either master and slave mode. In your case status
bits are separated between master and slave.
BTW I need to think about it.