[PATCH 4/4] gpio: pca953x: Add DT binding for reset gpio

Linus Walleij linus.walleij at linaro.org
Thu Aug 28 23:27:16 PDT 2014


On Thu, Aug 14, 2014 at 11:21 AM, Philipp Zabel <p.zabel at pengutronix.de> wrote:
> Am Montag, den 11.08.2014, 10:43 +0200 schrieb Linus Walleij:
>> On Fri, Aug 8, 2014 at 4:11 PM, Philipp Zabel <p.zabel at pengutronix.de> wrote:
>> > Am Freitag, den 08.08.2014, 15:14 +0200 schrieb Linus Walleij:

>> >> As it happens, Houcheng Lin has already proposed such a
>> >> driver:
>> >> http://marc.info/?l=linux-kernel&m=140309916607115&w=2
>> >
>> > That is a different issue, as there the device does not appear on the
>> > bus until the reset is released.
>>
>> You're just looking at the patch description. Look at what the
>> driver does.
>>
>> I wrote this reply to the patch:
>> http://marc.info/?l=linux-kernel&m=140480593524472&w=2
>>
>> With a delay of zero, the reset will be released
>> immediately, by the use of a helper OF node and this driver
>> from the reset subsystem. It's nice, generic code that solves
>> a generic problem of deasserting GPIO lines for
>> some reset.
>
> Yes, it does what you want. But its purpose is different, it's a bit
> indirect for the use case at hand,

I think a generic driver is always best, define what you mean
by "indirect" in this context.

> and we'll still find cases where this
> won't work (interaction with other pins).

But that is not what you're trying to solve right now.

> As to whether the sub-node
> might conflict with existing bindings, I don't know. This is something
> that should be taken to devicetree discussion list.

Um? I don't get this.

Yours,
Linus Walleij



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