[U-Boot] [PATCH 3/9] drivers: nand: Kconfig: add NAND as Kconfig option

[Scott Wood <oss@buserror.net>]

On Fri, 2016-04-08 at 15:45 -0400, Tom Rini wrote:
> On Tue, Apr 05, 2016 at 02:07:46PM +0530, Mugunthan V N wrote:
> > Scott/Tom
> > 
> > On Saturday 02 April 2016 05:55 AM, Tom Rini wrote:
> > > On Fri, Apr 01, 2016 at 06:45:03PM -0500, Scott Wood wrote:
> > > > On Fri, 2016-04-01 at 19:41 -0400, Tom Rini wrote:
> > > > > On Fri, Apr 01, 2016 at 06:07:18PM -0500, Scott Wood wrote:
> > > > > 
> > > > > > On Fri, 2016-04-01 at 08:51 -0400, Tom Rini wrote:
> > > > > > > On Fri, Apr 01, 2016 at 04:59:44PM +0530, Mugunthan V N wrote:
> > > > > > > 
> > > > > > > > Add CONFIG_NAND as a Kconfig option so that it can be selected
> > > > > > > > using menuconfig or defconfig.
> > > > > > > > 
> > > > > > > > Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
> > > > > > > 
> > > > > > > Good but you need to update configs/ to remove NAND from
> > > > > > > CONFIG_SYS_EXTRA_OPTIONS and add CONFIG_NAND=y
> > > > > > 
> > > > > > NACK
> > > > > > 
> > > > > > That CONFIG_NAND is a target-local option used by some boards to
> > > > > > indicate
> > > > > > boot
> > > > > > source.  It is not equivalent to CONFIG_CMD_NAND which is what
> > > > > > enables the
> > > > > > NAND subsystem.
> > > > > 
> > > > > Exactly!  We need to have 'NAND' moved from CONFIG_SYS_EXTRA_OPTIONS
> > > > > and
> > > > > into a real Kconfig entry.  That said, I think this might have
> > > > > forgotten
> > > > > to enable it in other places too but just 'NAND' needs to migrate
> > > > > out of
> > > > > where it is.
> > > > 
> > > > If we must start using NAND rather than CMD_NAND to enable the NAND
> > > > subsystem
> > > > (which is what this patch does), then a lot more than that needs to
> > > > change. 
> > > >  We'll need a new name for the boot source selection, and we'll need
> > > > to
> > > > kconfigize all the boards that enable CONFIG_CMD_NAND via the board
> > > > config
> > > > header.
> > > 
> > > OK, I see your point now too.  Yes, we need to tackle NAND/CMD_NAND
> > > Kconfig stuff (including the tangled web of CMD_NAND being how we toggle
> > > NAND the functionality) as a pre-patch series to this.  But it needs
> > > doing :)
> > 
> > Should I be moving back NAND to "CONFIG_SYS_EXTRA_OPTIONS"?
> > 
> > Since CONFIG_CMD_NAND is used to enable NAND subsystem, so move
> > CONFIG_CMD_NAND to drivers/mtd/nand/Kconfig?
> > 
> > or am I missing something?
> 
> I would like to see, but I want to hear Scott's opinion, move to
> CONFIG_NAND is what enables NAND support for everyone (so yes, lots of
> defconfigs will need an update) so that we can move it all over to
> Kconfig.

I'm fine with changing the names as long as everything gets updated properly. 
 The boards which use CONFIG_NAND to mean NAND boot (which is a relic of an
old and dead config mechanism that parsed extra words added to a target name)
can be changed to CONFIG_NAND_BOOT.

-Scott