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