On Mon, Oct 19, 2015 at 10:29 AM, David Woodhouse [off-list ref] wrote:

On Mon, 2015-10-19 at 15:50 +0100, Mark Brown wrote:

quoted

quoted

But the point I'm making is that we are working towards *fixing* that,
and *not* using DT-specific code in places where we should be using the
generic APIs.

What is the plan for fixing things here?  It's not obvious (at least to
me) that we don't want to have the subsystems having knowledge of how
they are bound to a specific firmware which is what you seem to imply
here.

I don't know that there *is* a coherent plan here to address it all.

Certainly, we *will* need subsystems to have firmware-specific
knowledge in some cases. Take GPIO as an example; ACPI *has* a way to
describe GPIO, and properties which reference GPIO pins are intended to
work through that — while in DT, properties which reference GPIO pins
will have different contents. They'll be compatible at the driver
level, in the sense that there's a call to get a given GPIO given the
property name, but the subsystems *will* be doing different things
behind the scenes.

My plan, such as it is, is to go through the leaf-node drivers which
almost definitely *should* be firmware-agnostic, and convert those. And
then take stock of what we have left, and work out what, if anything,
still needs to be done.

Many cases are already agnostic in the drivers in terms of the *_get()
functions. Some are DT specific, but probably because those subsystems
are new and DT only. In any case, I don't think these 1 line changes
do anything to make doing conversions here harder.

quoted

It seems like we're going to have to refactor these bits of code when
they get generalised anyway so I'm not sure that the additional cost
here is that big.

That's an acceptable answer — "we're adding legacy code here but we
know it's going to be refactored anyway". If that's true, all it takes
is a note in the commit comment to that effect. That's different from
having not thought about it :)

Considering at one point we did create a fwnode based API, we did
think about it. Plus there was little input from ACPI folks as to
whether the change was even useful for ACPI case. In any case, we're
talking about adding 1 line.

Rob