From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Daniel Mack <zonque@gmail.com>
Subject: Re: [PATCH 0/4] gpio: pxa: integrate with pincontrol
Date: Thu, 10 Dec 2015 18:31:08 +0100 [thread overview]
Message-ID: <87d1uejjmr.fsf@belgarion.home> (raw)
In-Reply-To: <CACRpkdZP=3mDWxoX6PRskztoeow41T9RgDyh82NP1=xnY+S1nQ@mail.gmail.com> (Linus Walleij's message of "Thu, 10 Dec 2015 16:02:12 +0100")
Linus Walleij <linus.walleij@linaro.org> writes:
>> - the GPDR (gpio direction register) shared access bothers me a bit
>
> How is it shared and between what users?
It's shared between the pin controller and the gpio controller.
The odd thing with the pxa architecture is that the GPDR bit selects between 2
different alternate functions, even when the pin is not a GPIO. Strange design,
isn't it ?
As a consequence, both the gpio driver and pinctrl have to modify it, for
different purposes :
- pinctrl will modify it to select a specific alternate function
- gpio driver will modify it when the pin is a GPIO, to modify its direction.
Cheers.
--
Robert
next prev parent reply other threads:[~2015-12-10 17:31 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-28 21:37 [PATCH 0/4] gpio: pxa: integrate with pincontrol Robert Jarzmik
2015-11-28 21:37 ` [PATCH 1/4] gpio: pxa: convert to one gpiochip Robert Jarzmik
2015-12-10 15:04 ` Linus Walleij
2015-12-10 17:28 ` Robert Jarzmik
2015-11-28 21:37 ` [PATCH 2/4] gpio: pxa: convert to devm_ioremap Robert Jarzmik
2015-12-10 15:05 ` Linus Walleij
2015-11-28 21:37 ` [PATCH 3/4] gpio: pxa: change the interrupt management Robert Jarzmik
2015-11-28 23:23 ` kbuild test robot
2015-11-29 10:03 ` Robert Jarzmik
2015-12-10 15:06 ` Linus Walleij
2015-11-28 21:37 ` [PATCH 4/4] gpio: pxa: add pin control gpio direction and request Robert Jarzmik
2015-12-10 17:33 ` Robert Jarzmik
2015-12-09 22:58 ` [PATCH 0/4] gpio: pxa: integrate with pincontrol Linus Walleij
2015-12-10 7:28 ` Robert Jarzmik
2015-12-10 15:02 ` Linus Walleij
2015-12-10 17:31 ` Robert Jarzmik [this message]
2015-12-14 13:42 ` Linus Walleij
2015-12-14 21:10 ` Robert Jarzmik
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