[PATCH] ARM: Keystone: Introduce Kconfig option to compile in typical Keystone features

On Wednesday, June 8, 2016 2:47:48 AM CEST Tony Lindgren wrote:

* Arnd Bergmann [off-list ref] [160607 01:11]:

quoted

A lot of these options are typical for all ARMv7 machines: AEABI, I2C, NEON,
PM, REGULATOR and VFP are things that we probably want to default to enabled
whenever we build a MULTI_V7 kernel, some also for V5 or V6, we just
need to come up with a good way to do that while (probably for most of
them) still allowing them to be disabled with CONFIG_EXPERT. I would
feel more comfortable with having an ARCH_MULTIPLATFORM_TYPICAL
Kconfig symbol than with the ARCH_OMAP2PLUS_TYPICAL one that ends up
turning things on unconditionally whenever you add ARCH_OMAP2PLUS
to some other configuration.

We still need to be careful about not changing the Kconfig option
name for something like this as it will cause the custom .config files
to fail unless the default is y. But yeah I agree, it would be nice
to have some multiarch sane default selects, then also do the platform
specific selects as needed. Naturally this needs to be kept down to
minimum ideally limited to silent options.

So we could have ARCH_MULTIPLATFORM_TYPICAL, then have the old
ARCH_OMAP2PLUS_TYPICAL select that one. That should keep things
behaving just fine if the old .config had ARCH_OMAP2PLUS_TYPICAL.

If we make ARCH_MULTIPLATFORM_TYPICAL 'default y', it will be always
enabled in this case, and I think we can drop ARCH_OMAP2PLUS_TYPICAL.

The downside would be any users that want the options we enable there
turned off and have them silently enabled when upgrading the kernel.

quoted

For I2C_OMAP, MENELAUS and TWL4030, we could just add a
'default ARCH_OMAP3 || ARCH_OMAP4' or whatever is appropriate for
each of them. I assume we want to handle TWL6040 the same way, though
we currently don't do that. MENELAUS seems to be only needed for
omap2420-n8x0.

We could yeah. TWL4030 is omap2430 to omap3, I don't think we currently
have any omap3 based ones not using twl4030.. But there certainly
are tons of usable devices with the Motorola CPCAP PMIC instead.

So should we enable both then?

Then REGULATOR_FIXED_VOLTAGE we can have platform select like Mark
seems to prefer. 

Ok

HIGHMEM too should be platform specific.

I still don't see a good way to handle that, we should certainly not
just 'select' it, because we often want to leave it disabled.

The original reason for ARCH_OMAP2PLUS_TYPICAL was that if omap2plus
is selected with that you actually get a bootable system.

I understand. It's just not very scalable to have every platform do
this, in particular if they want to select conflicting options (none
of the ones you select should conflict, but we'd get there eventually).

	Arnd