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From: Alexandre Courbot <gnurou@gmail.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <acourbot@nvidia.com>,
	Mark Brown <broonie@kernel.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] gpio: add flags argument to gpiod_get*() functions
Date: Thu, 31 Jul 2014 12:43:32 +0900	[thread overview]
Message-ID: <CAAVeFuK0qe9Hi8OZv9pJjZYFZB_DexPJOD-D2=4DSG==7nHkJg@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdZLXr7mTD4H1VXQPqrwZ3gcjU7CtehOK1-1_=L1J3OnfQ@mail.gmail.com>

On Mon, Jul 28, 2014 at 7:30 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Fri, Jul 25, 2014 at 4:38 PM, Alexandre Courbot <acourbot@nvidia.com> wrote:
>
>> The huge majority of GPIOs have their direction and initial value set
>> right after being obtained by one of the gpiod_get() functions. The
>> integer GPIO API had gpio_request_one() that took a convenience flags
>> parameter allowing to specify an direction and value applied to the
>> returned GPIO. This feature greatly simplifies client code and ensures
>> errors are always handled properly.
>>
>> A similar feature has been requested for the gpiod API. Since setting
>> the direction of a GPIO is so often the very next action done after
>> obtaining its descriptor, we prefer to extend the existing functions
>> instead of introducing new functions that would raise the
>> number of gpiod getters to 16 (!).
>>
>> The drawback of this approach is that all gpiod clients need to be
>> updated. To limit the pain, temporary macros are introduced that allow
>> gpiod_get*() to be called with or without the extra flags argument. They
>> will be removed once all consumer code has been updated.
>>
>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>> ---
>> This dude can be applied harmlessly to the GPIO tree - then I will go
>> after every gpiod user to update the calls to gpiod_get*() before
>> removing the macros in consumer.h.
>
> OK I trust you. Patch applied with Broonie's review tag.

Thanks! Unfortunately it is still not in -next due to a build error...

> Just so we don't forget how we should move forward: Alex what do
> you think about adding a drivers/gpio/TODO.TXT file outlining the
> overall plan of the gpiod refactoring and clean-up work?

I have such a file locally - I'm not sure if checking it into the
kernel tree is relevant though. Sounds more like the task of a wiki
page.

  reply	other threads:[~2014-07-31  3:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-25 14:38 [PATCH] gpio: add flags argument to gpiod_get*() functions Alexandre Courbot
2014-07-25 16:15 ` Mark Brown
2014-07-28 10:30 ` Linus Walleij
2014-07-31  3:43   ` Alexandre Courbot [this message]
2014-08-04  5:04     ` Alexandre Courbot

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