Re: [PATCH v2] mtd: nand: denali: allow to override max_banks from DT property

[Masahiro Yamada]

2016-03-29 11:33 GMT+09:00 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>:
> Commit 271707b1d817 ("mtd: nand: denali: max_banks calculation
> changed in revision 5.1") supported the new encoding of the "n_banks"
> bits of the "features" register, but there is an unfortunate case
> not covered by that commit.
>
> Panasonic (its System LSI Business Division is now Socionext) bought
> a couple of versions of this IP.  The IP released for Panasonic
> around Feb. 2012 is revision 5 and uses the old encoding for n_banks
> (2 << n_banks).  While the one released around Nov. 2012 is also
> revision 5, but it uses the new encoding (1 << n_banks).
>
> The revision register cannot distinguish these two incompatible
> hardware.  I guess this IP series is not well-organized.  I could not
> find any solution but giving max_banks from DT property.
>
> This commit works around the problem by allowing DT to set the
> max_banks forcibly.  Of course, this DT property can be optional if
> the auto detection based on the hardware registers works well.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>


Looks like we should take our time for discussion
to find out which is better, a new compatible string or a new DT property.

The discussion is happening in v1 thread.
http://patchwork.ozlabs.org/patch/601562/

Please hold back applying this patch.



-- 
Best Regards
Masahiro Yamada