[PATCH] mtd: nand: auto-detection of NAND bus-width from ONFI param or nand_id[]

[Gupta, Pekon]

> From: Ezequiel Garcia [mailto:ezequiel.garcia at free-electrons.com]
[...]
> My point is: why don't we *remove* the devicetree property nand-bus-
> width and 
> 
We cannot remove DT property like this, we can only deprecate its use,
while not breaking the functionality, which is what I'm trying here..
To completely remove a DT binding it needs approval and Ack by DT
maintainers. And over that DT binding has too still remain deprecated for
sometime till all users have migrated to newer version of kernel.
(hope you remember reviews of my earlier omap-nand patches which
updated few DT bindings :-) )...

However there should be some lifetime associated with DT bindings,
I heard David W. participated in some DT binding related discussion in
some linux conference. May be he can throw more light on "how to 
phase out unused DT bindings?"


> the NAND_BUSWIDTH_16 entirely, together with this patch?
> 
We need this Macros, as may driver use this after nand_scan_ident()
to configure their custom callbacks like:
	if (chip->options & NAND_BUSWIDTH_16)
		chip->read_buf = omap_read_buf16;
	else 
		chip->read_buf = omap_read_buf8;


> Sounds like the user shouldn't need to mess with any of these, since we
> are able to auto-configure things for him.
> 
Yes, end-user is free.. But driver still needs to x16 and x8 information
to do some controller level optimizations..


with regards, pekon