There are two parts for device to be ready to talk at bus level: 1> power up and reset, 2> enumerate and assign a logical address by the slimbus controller.
First part as you said is already done in probe. When second part happens when status callback is invoked, that is when the slimdevice is ready for any kind of communication at bus level.
I see. I still think it's hacky to conduct start-up procedures when all the SS requested was status. Perhaps it needs a new API call init()?
When we added these callbacks the purpose of this was to allow drivers to do specific setup/teardown.
AFIAU, even-though if we add init(), SLIMbus would still call it just before or after status which to me is redundant ATM. Its up to slim driver what it exactly whats to do with status, in some cases this can involve setting up the device.