linux-kernel - Re: [PATCH 2/2] HID: i2c-hid: Add support for GPIO interrupts

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Message-ID: <20150127144127.GT1451@lahna.fi.intel.com>
Date:	Tue, 27 Jan 2015 16:41:27 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Mark Rutland <mark.rutland@....com>
Cc:	Jiri Kosina <jkosina@...e.cz>,
	Benjamin Tissoires <benjamin.tissoires@...hat.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <Pawel.Moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] HID: i2c-hid: Add support for GPIO interrupts

On Tue, Jan 27, 2015 at 02:33:34PM +0000, Mark Rutland wrote:
> Ok, that allays my fear w.r.t. ordering of the resources.
> 
> As I see it, the fact that we convert GpioInt entries to GPIOs rather
> than irqs when parsing _CRS is the issue here, and to me it makes no
> sense that we do so. Were we to treat them as interrupts, the binding is
> fine as-is, and we'd do the same thing in DT and ACPI.
> 
> The reason GpioInt is separate from GpioIo is that a GpioInt _is_ an
> interrupt (which happens to be backed by a GPIO), and is not something
> that necessarily makes sense as a GPIO.

I would rather say that GpioInt *is* a GPIO. That can then used as an
interrupt but it should not prevent you from using it as GPIO instead.
For example if you just want to poll that something is 0 or 1. That
should be possible as well and nothing say that you cannot do that for
GpioInt().

> So why do we currently ignore the GpioInt/GpioIo distinction and treat
> GpioInts as GPIOs rather than interrupts?

See above.
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