GPIO MPC8315 board

DISCUSSION Vasanth Ragavendran 2 participants 2 messages Jun 22, 2011

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Vasanth Ragavendran

author

2011-06-22 08:56 UTC #0 lore raw

Hi
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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 tha= t
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_GPIOLI= B
etc. And the dts file has be modified to include the following lines=20 =20
gpio1: gpio-controller@c00 { =20
#gpio-cells =3D <2>; =20
compatible =3D "fsl,mpc8315-gpio", "fsl,mpc8349-gpio"; =20
reg =3D <0xc00 0x100>; =20
interrupts =3D <74 0x8>; =20
interrupt-parent =3D <&ipic>; =20
gpio-controller; }; =20
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this is included under immr@e0000000.
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further i included
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erase-button@0 {
compatible =3D "erase-button";
interrupts =3D <7 2>;
interrupt-parent =3D <&gpio1>;
};
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am i right in including this? coz after compiling the kernel i get a folder under /sys/class/gpio. I did an export using
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echo 224 > /sys/class/gpio/export.
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224 was the number appearing in gpiochip224/base.
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It created another folder gpio224.
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However i'm not able to set the value in them nor the direction. =20
echo 1 > /sys/class/gpio/gpio224/value
cat /sys/class/gpio/gpio224/value=EF=BB=BF
returns a value of 0 only.
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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!
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My kernel version is 2.6.35.9.
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Thanking you in advance.
--=20
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Martyn Welch

2011-06-22 09:42 UTC #1 lore raw

Quoted 39 lines · Vasanth Ragavendran

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.

Quoted 8 lines

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

Quoted 6 lines

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.

Signature · 4 lines

Martyn Welch (Principal Software Engineer) | Registered in England and
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