Re: GPIO MPC8315 board

[Martyn Welch <martyn.welch@ge.com>]

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.


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