[PATCH] RFC: pinctrl: grab default handler with bus notifiers

Linus Walleij linus.walleij at linaro.org
Fri Nov 16 06:36:33 EST 2012


On Thu, Nov 15, 2012 at 7:23 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 11/15/2012 07:03 AM, Linus Walleij wrote:

>> OK I'll have to come up with a patch to the device core
>> instead... it'll be much simpler anyway and if both of you guys
>> can back it I guess Greg might be OK with it too.
>
> I did have one thought here; how will this interact with hogs? If a
> device's pinctrl configuration must be pinctrl_get()'d before the device
> is probed, then a pinctrl device with hogs will never get probed because
> it won't be registered to provide the pinctrl node parsing.

Catch 22 :-(

Yeah we need to come up with something there.

> Solutions might include:
>
> a) Some special case where if the pinctrl driver only can't probe due to
> missing pinctrl from its own node, don't defer the probe, but defer the
> pinctrl_get().
>
> b) Separate out DT node parsing from device instantiation, so that the
> driver can always parse the DT, without needing the context of a
> specific pinctrl device to do so.

But this mechanism can't be device tree-specific, we have some
of olschool pdata users and ACPI probing around the corner.

I will likely just cook up something like seeing if the
dev_name() for provider and consumer is the same and
in that case avoid deferral.

Oh well, I'll try to actually code this now...

Yours,
Linus Walleij



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