The checks should function as follows:
* AR_SREV_<silicon> : check macVersion matches that version id
* AR_SREV_<silicon>_<revision> : check macVersion and macRevision match
the version / revision respectively
* AR_SREV_<silicon>_<revision>_OR_LATER: check that
+ if the chip silicon version == macVersion, enforce revision >= macRevision
+ if the chip silicon version > macVersion, allow it.
For example, AR_SREV_MERLIN() only matches AR9280 (any revision),
AR_SREV_MERLIN_10() would only match AR9280 version 1.0, but
AR_SREV_MERLIN_20_OR_LATER() matches AR9280 version >= 2.0 _AND_
any subsequent MAC (So AR9285, AR9287, etc.)
The specific fixes which may impact users:
* if there is Merlin hardware > revision 2.0, it'll now be correctly
matched by AR_SREV_MERLIN_20_OR_LATER() - the older code simply
would match on either Merlin 2.0 or a subsequent MAC (AR9285, AR9287, etc.)
* Kite version 1.1/1.2 should now correctly match. As these macros
are used in the AR9285 reset/attach path, and it's assumed that the
hardware is kite anyway, the behaviour shouldn't change. It'll only
change if these macros are used in other codepaths shared with
older silicon.
Obtained from: Linux ath9k, Atheros
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