Re: [PATCH v4 1/9] mfd: AXP20x: Add mfd driver for AXP20x PMIC

[Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Fri, Apr 11, 2014 at 01:25:03PM +0200, Arnd Bergmann wrote:

> Why do you have to enumerate the interrupts here? Can't you just
> put all the numbers into the DT nodes of the devices using them?

> In general, I would say that the mfd driver should not care about
> what is connected to it.

This then means that all the machines using the device need to define
the interrupt table and have the MFD cells represented in the DT which
means encoding Linux abstractions into the DT.

In cases where the device is also used with ACPI or platform data that's
a definite issue since they have different idioms.  That applies less to
PMICs tightly bound to particular SoCs but is an issue in general, not
all the world is DT.

There's also issues here with us changing our subsystems.  Things like
clocks are a bit indistinct at present, they're sort of floating between
clock and other subsystems.  We've also done things like invent extcon,
making completely new subdevices.  Keeping the data out of DT avoids
problems when this happens.  The balance changes a bit if there are
clearly reusable IPs within the device but sadly hardware designers
don't always give us that and even then sometimes we don't want to use
them like that.

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