On Mon, Jul 27, 2020 at 1:57 PM Arnd Bergmann [off-list ref] wrote:

Overall, my feeling is that making sure all drivers that depend on the pinctrl
driver can deal with deferred probing is a prerequisite before this can be
made a loadable module itself (same for clk, irqchip, etc drivers that others
may rely on).

I understand that your primary motivation is to fit into Google's GKI framework,
but I think that doing the conversion only partially would neither serve to
improve the kernel nor actually meet the GKI requirements.

This has been my worry as well when it comes to these GKI-initiated
patches that are flying right now.

Most pinctrl drivers are currently always built-in to work around the
load order dependencies. This of course is a bit of a hack and we'd be
better off if all drivers managed to avoid the dependencies, but this
can also require a lot of work.

Several people have argued that it is reasonable to cut corners to
achieve the "greater good" of GKI.

I try to handle it on a "does the kernel look better after than
before" basis, while pushing gently for at least trying to
properly modularize the whole thing. It can become pretty hard
to test I think. If it is things like GPIO expanders on I2C
that can be used by several SoCs I would be more hard on
this, on a single SoC not as much.

One discussion thread got inflamed because of ARM vs x86
discussions "x86 is better modularized" which is something I want
to avoid, it is easy to be modularized when your irqs, clocks,
regulators and pins are handled by the BIOS. This is a SoC
problem and x86 SoCs with no BIOS, RISCV, ARM and whatever
doesn't have a fix-it-all-BIOS have this problem. :/

Yours,
Linus Walleij

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