These drivers are not bus drivers, and would need proper detach
routines that tore down state stored in the softc. Better to just
fail detach outright instead of an incorrect success.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D47389
(cherry picked from commit 7ebc7d1ab76b9d06be9400d6c9fc74fcc43603a1)
This basic version of the driver obtains properties of the "sff,sfp"
compatible devices and implements a simple interface to provide an I2C
bus device for the rest of the drivers (e.g. to implement SIOCGI2C).
Both of the interface and driver are subjects for a further
generalization to be used in case of non-FDT and non-arm64 platforms.
Reviewed by: bz, manu
Approved by: bz (mentor)
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D41440
