linux-kernel - Re: [RFC v2] gpio/omap: auto-setup a GPIO when used as an IRQ

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Message-ID: <20130924155808.GP2684@atomide.com>
Date:	Tue, 24 Sep 2013 08:58:08 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	Santosh Shilimkar <santosh.shilimkar@...com>
Cc:	Balaji T K <balajitk@...com>,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Kevin Hilman <khilman@...aro.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Stephen Warren <swarren@...dotorg.org>,
	Lars Poeschel <larsi@....tu-dresden.de>,
	Grant Likely <grant.likely@...aro.org>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ian.campbell@...rix.com>,
	Kumar Gala <galak@...eaurora.org>,
	Pawel Moll <pawel.moll@....com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Enric Balletbo i Serra <eballetbo@...il.com>,
	Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>,
	Jon Hunter <jgchunter@...il.com>, linux-gpio@...r.kernel.org,
	linux-omap@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, r.sricharan@...com,
	holler@...oftware.de
Subject: Re: [RFC v2] gpio/omap: auto-setup a GPIO when used as an IRQ

* Santosh Shilimkar <santosh.shilimkar@...com> [130924 08:56]:
> On Tuesday 24 September 2013 11:45 AM, Balaji T K wrote:
> > On Tuesday 24 September 2013 09:10 PM, Tony Lindgren wrote:
> >> * Javier Martinez Canillas <javier.martinez@...labora.co.uk> [130924 01:06]:
> >>> The OMAP GPIO controller HW requires a pin to be configured in GPIO
> >>> input mode in order to operate as an interrupt input. Since drivers
> >>> should not be aware of whether an interrupt pin is also a GPIO or not,
> >>> the HW should be fully configured/enabled as an IRQ if a driver solely
> >>> uses IRQ APIs such as request_irq(), and never calls any GPIO-related
> >>> APIs. As such, add the missing HW setup to the OMAP GPIO controller's
> >>> irq_chip driver.
> >>>
> >>> Since this bypasses the GPIO subsystem we have to ensure that another
> >>> caller won't be able to request the same GPIO pin that is used as an
> >>> IRQ and set its direction as output. Requesting the GPIO and setting
> >>> its direction as input is allowed though.
> >>
> >> Also please mention the regression that this fixes. So far we know
> >> that smsc911x for tobi and igep boards in mainline, and also the
> > 
> >> MMC card detect for omap4 boards.
> > Hi Tony,
> > 
> > Card detect on omap4 board (sdp and panda) is not based on omap gpio,
> > so I think this fix is not applicable for omap4.
> > 
> > Card detect line for SD card goes to power IC on OMAP4 panda and SDP.
> > 
> I confused Tony mostly. It was OMAP4 SPI based ethernet which uses the
> GPIO as an interrupt line.
> 
> So for Panda, its Ethernet driver and not MMC.

OK :) Thanks for clarifying.

Tony
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