From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from exprod5og110.obsmtp.com (exprod5og110.obsmtp.com [64.18.0.20]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C2131B6F94 for ; Wed, 22 Jun 2011 19:42:37 +1000 (EST) Message-ID: <4E01B7D3.1010700@ge.com> Date: Wed, 22 Jun 2011 10:37:23 +0100 From: Martyn Welch MIME-Version: 1.0 To: linuxppc-dev@lists.ozlabs.org Subject: Re: GPIO MPC8315 board References: <31901492.post@talk.nabble.com> In-Reply-To: <31901492.post@talk.nabble.com> Content-Type: text/plain; charset=UTF-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 22/06/11 09:56, Vasanth Ragavendran wrote: > > Hi > > I am using a MPC8315ERDB board. For this i've an external button which is > connected to GPIO pin 7 of the board. And if this button is pressed then > certain files have to be deleted. Browsing through the internet i found that > GPIO drivers have to be included into the kernel and hence i set a 'y' to > CONFIG_MPC8xxx_GPIO, CONFIG_GPIO_SYSFS and CONFIG_ARCH_WANT_OPTIONAL_GPIOLIB > etc. And the dts file has be modified to include the following lines > > gpio1: gpio-controller@c00 { > #gpio-cells = <2>; > compatible = "fsl,mpc8315-gpio", "fsl,mpc8349-gpio"; > reg = <0xc00 0x100>; > interrupts = <74 0x8>; > interrupt-parent = <&ipic>; > gpio-controller; }; > > this is included under immr@e0000000. > > further i included > > erase-button@0 { > compatible = "erase-button"; > interrupts = <7 2>; > interrupt-parent = <&gpio1>; > }; > > am i right in including this? coz after compiling the kernel i get a folder > under /sys/class/gpio. I did an export using > > echo 224 > /sys/class/gpio/export. > > 224 was the number appearing in gpiochip224/base. > > It created another folder gpio224. > > However i'm not able to set the value in them nor the direction. > > echo 1 > /sys/class/gpio/gpio224/value > cat /sys/class/gpio/gpio224/value > returns a value of 0 only. > > however the direction is "in" > cat /sys/class/gpio/gpio224/direction > in > echo "out" > /sys/class/gpio/gpio224/direction Martyn > Am i doing it correctly? How to check it programatically if the button is > pressed and take the corresponding action! Plz help! > > My kernel version is 2.6.35.9. > > Thanking you in advance. -- Martyn Welch (Principal Software Engineer) | Registered in England and GE Intelligent Platforms | Wales (3828642) at 100 T +44(0)127322748 | Barbirolli Square, Manchester, E martyn.welch@ge.com | M2 3AB VAT:GB 927559189