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GPIO MPC8315 board

Question asked by Vasanth Ragavendran Raja Sekaran on Jun 22, 2011
Latest reply on Jun 27, 2011 by Vasanth Ragavendran Raja Sekaran



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 192 > /sys/class/gpio/export.


192 was the number appearing in gpiochip192/base.


It created another folder gpio192.


However i'm not able to set the value in them nor the direction.


echo 1 > /sys/class/gpio/gpio192/value

cat /sys/class/gpio/gpio192/value

returns a value of 0 only.


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


Thanking you in advance.