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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Sun, 1 May 2022 23:55:31 +0200
Message-ID: <CACRpkdaha37y-ZNSqYSbf=TvsJNcvbH1Y=N0JkVCewB-Lvf81Q@mail.gmail.com>
Subject: Re: [RFC v2 10/39] gpio: add HAS_IOPORT dependencies
To:     William Breathitt Gray <william.gray@linaro.org>
Cc:     Niklas Schnelle <schnelle@linux.ibm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-pci@vger.kernel.org, Arnd Bergmann <arnd@kernel.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>
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On Fri, Apr 29, 2022 at 5:37 PM William Breathitt Gray
<william.gray@linaro.org> wrote:
> On Fri, Apr 29, 2022 at 04:46:00PM +0200, Niklas Schnelle wrote:

> > Good question. As far as I can see most (all?) of these have "select
> > ISA_BUS_API" which is "def_bool ISA". Now "config ISA" seems to
> > currently be repeated in architectures and doesn't have an explicit
> > HAS_IOPORT dependency (it maybe should have one). But it does only make
> > sense on architectures with HAS_IOPORT set.
>
> There is such a thing as ISA DMA, but you'll still need to initialize
> the device via the IO Port bus first, so perhaps setting HAS_IOPORT for
> "config ISA" is the right thing to do: all ISA devices are expected to
> communicate in some way via ioport.

Adding that dependency seems like the right solution to me.

Yours,
Linus Walleij