linux-kernel - Re: [PATCH v4 1/2] gpio: Add support for IDT 79RC3243x GPIO controller

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Date:   Wed, 28 Apr 2021 13:57:17 +0200
From:   Michael Walle <michael@...le.cc>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH v4 1/2] gpio: Add support for IDT 79RC3243x GPIO
 controller

Am 2021-04-28 13:07, schrieb Andy Shevchenko:
> On Wed, Apr 28, 2021 at 1:51 AM Michael Walle <michael@...le.cc> wrote:
>> Am 2021-04-26 12:29, schrieb Andy Shevchenko:
>> > On Mon, Apr 26, 2021 at 12:55 PM Thomas Bogendoerfer
>> > <tsbogend@...ha.franken.de> wrote:
>> >
>> > 2) there is gpio-regmap generic code, that may be worth
>> > considering.
>> 
>> This driver uses memory mapped registers. While that is
>> also possible with gpio-regmap, there is one drawback:
>> it assumes gpiochip->can_sleep = true for now, see [1].
>> Unfortunately, there is no easy way to ask the regmap
>> if its mmio/fastio.
> 
> I don't see how it is an impediment.

You'd have to use the *_cansleep() variants with the gpios,
which cannot be used everywhere, no?

-michael