[U-Boot] [PATCH v2 1/2] drivers; add DM_NO_OF Kconfig option

[Simon Glass]

Hi Angelo,

On 30 May 2018 at 13:58, Angelo Dureghello <angelo at sysam.it> wrote:
> Hi Tom and Simon,
>
> thanks for the support.
>
> On Mon, May 28, 2018 at 08:59:21PM -0400, Tom Rini wrote:
>> On Sun, May 27, 2018 at 07:45:12PM -0600, Simon Glass wrote:
>> > +Tom
>> >
>> > Hi Angelo,
>> >
>> > On 27 May 2018 at 01:22, Angelo Dureghello <angelo at sysam.it> wrote:
>> > > Hi Simon,
>> > >
>> > > On Sat, May 26, 2018 at 04:18:57PM -0600, Simon Glass wrote:
>> > >> Hi Angelo,
>> > >>
>> > >> On 3 May 2018 at 16:01, Angelo Dureghello <angelo at sysam.it> wrote:
>> > >> > To be able to build spi driver with DM support, a new config
>> > >> > option has been introduced (DM_NO_OF) since m68k architecture
>> > >> > does not support fdt.
>> > >> >
>> > >> > ---
>> > >> > Changes from v1:
>> > >> > - split into 2 patches
>> > >> >
>> > >> > Signed-off-by: Angelo Dureghello <angelo at sysam.it>
>> > >> > ---
>> > >> >  arch/Kconfig             |  1 +
>> > >> >  drivers/core/Kconfig     |  4 ++++
>> > >> >  drivers/spi/spi-uclass.c | 12 +++++++-----
>> > >> >  3 files changed, 12 insertions(+), 5 deletions(-)
>> > >> >
>> > >>
>> > >> Is it possible to use SPL_OF_PLATDATA instead?
>> > >>
>> > > I have seen that setting, but my understanding is that
>> > > SPL_OF_PLATDATA ws made for a different purpose, and also, i
>> > > tried to use it, but cannot select it from menuconfig.
>> > >
>> > >> How come m68k cannot use device tree?
>> > >>
>> > > There was never any devicetree implementation, probably becouse it
>> > > is missing on Linux too.
>> >
>> > It is a real shame that we can't do better than that.
>> >
>> > I've added Tom in for comment as I'm not sure what is best here.
>>
>> Yeah, I think as sandbox shows, if/when we don't have to worry about
>> also Linux dts files, it's not a lot of work to populate up what's
>> required for just U-Boot, so long as we have the run-time space.  And if
>> not, that's what OF_PLATDATA is for.
>>
>
> About SPL_OF_PLATDATA, do you think i can change it to a more generic
> OF_PLATDATA, or GENERIC_OF_PLATDATA not dependant from SPL (i am not
> using SPL) ?
> I also need to add "select SUPPORT_OF_CONTROL" for m68k arch.
>
> Let me know if the above is ok, otherwise i start to work for the
> devicetree option.

I am nervous about it since it opens the door to people using
OF_PLATDATA in U-Boot proper, which I was hoping to avoid. If you look
at the code you will see that it is somewhat ugly. Fine for SPL since
it reduces the size so much, but the size advantage would be less in
U-Boot (since we have libfdt anyway).

So my preference would be to add device tree. But it's not the end of the world.

What do you think, Tom?

Regards,
Simon