[PATCH v2][POWERPC] document ipic level/sense info

[Yoder Stuart-B08248]

> -----Original Message-----
> From: Segher Boessenkool [mailto:segher at kernel.crashing.org] 
> Sent: Tuesday, July 10, 2007 8:21 AM
> To: Grant Likely
> Cc: Yoder Stuart-B08248; linuxppc-dev at ozlabs.org; paulus at samba.org
> Subject: Re: [PATCH v2][POWERPC] document ipic level/sense info
> 
> >> +Sense and level information follows the Linux convention
> >> +(specified in include/linux/interrupt.h) and should be encoded
> >> +as follows:
> >> +
> >> +       2 =  high to low edge sensitive type enabled
> >> +       8 =  active low level sensitive type enabled
> 
> > ... but it is probably worthwhile commentting that sense types 1 & 4
> > are not supported; just to fill in the obvious gaps.  :-)
> 
> Same for sense types 0, 3, 5, 6, ...
> 
> Just name the sense types 0 and 1, similar to what all other
> OF interrupt controller bindings do.

Actually, all I am trying to do with this patch is document the
current state of things.  The 2/8 sense type usage has been that
way for a long time, and I'll defer to the 83xx maintainers
if they see any value in changing it.

Right now there are many DTS files with level/sense set to values
like 8 and no indication anywhere where those values came from.

Stuart