GPIO MPC8315 board
Vasanth Ragavendran
ragavendrapec at yahoo.co.in
Wed Jun 22 18:56:06 EST 2011
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 at 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 at e0000000.
further i included
erase-button at 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
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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