adt7xxx drivers (Was Re: Device name length restriction?)

[Paul Goyette <paul%whooppee.com@localhost>]

Having looked more at both the adt7463 and adt7467 drivers, as well as 
writing a new(ish) driver for the adt7475, it occurs to me that all of 
these drivers are for a single chip family and that the drivers are (or 
can be) nearly identical, save for the specific set of sensors 
supported.  It seems to me that we could rather easily merge all of 
these drivers into a single addbc (for "Analog Devices dbCool") driver, 
detect the specific chip based on on-chip register contents (location 
is common to all of these drivers), and select the appropriate set of 
sensors from a chip-specific table.  There are a number of additional 
chips in the dbCool family, and having a single driver would make it 
easier to support more of them, at a small cost of some table space in 
the kernel.

While I'm at it, I noticed that the adt7467 driver has a sysctl node to 
enable read/write of the Tmin registers (used to set the threshold of 
when fans should be sped up).  Currently this sysctl lives under the 
machdep top-level node;  I'm assuming this is because the original 7467 
driver was intended only for the MacBook on which it was found.  I 
suspect that a more appropriate place for this sysctl is under the hw 
top-level node.

Comments?  Is it worthwhile to merge these drivers?  Worth the cost of 
the tables?  And should the sysctl be moved to hw.<dev_name>.xxx or 
leave it at machdep.<dev_name>.xxx ?



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