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

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Message-ID: <5241B465.5050604@ti.com>
Date:	Tue, 24 Sep 2013 11:48:53 -0400
From:	Santosh Shilimkar <santosh.shilimkar@...com>
To:	Balaji T K <balajitk@...com>
CC:	Tony Lindgren <tony@...mide.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

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.

Regards,
Santosh

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