devfs Gpio and interrupt

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I read gpio.txt in Documentation of kernel and try to use it.

I use:

# echo 13 > /sys/class/gpio/export
# echo in > /root/tasto1/direction=20
# cat /root/tasto1/direction
in

# cat /root/tasto1/value=20
1

when the button is pressed:
# cat /root/tasto1/value=20
0

# cat /root/tasto1/edge=20
none
# echo both > /root/tasto1/edge=20

# cat /sys/kernel/debug/gpio=20
[...]
B5 gpio-13 (sysfs ) in hi irq-77 edge-both
[...]

# cat /proc/irq/77/spurious p
count 15
unhandled 0
last_unhandled 0 ms
cat: p: No such file or directory
Ture:~# cat /proc/irq/77/spurious=20
count 15
unhandled 0
last_unhandled 0 ms


I try the follow code in a while (1):

// /root/tasto1 is a symbolic link to /sys/class/gpio/gpio13/

pfd.fd =3D open("/root/tasto1/value", O_RDONLY);
pfd.events =3D POLLPRI | POLLERR;=20

//ready =3D poll(&pfd, 1, -1);=20
ready =3D poll(&pfd, 1, 100000);=20

lseek (pfd.fd, 0, SEEK_SET);

val =3D read(pfd.fd, buf, 254);
//the output are: 1, 10, 10
printf ("%d, %d, %d\n", ready, pfd.revents, pfd.events);

printf ("%d, %s\n", val, buf );

close(pfd.fd);

But it don't wait for an edge but they exit immediatly.=20
Why? where is the problem?

--=20
Mancausoft - http://www.mancausoft.org/
GPG key: B53F90F2

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Re: devfs Gpio and interrupt

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On 15:22 Wed 09 Feb , Mancausoft wrote:
> I read gpio.txt in Documentation of kernel and try to use it.
> pfd.fd =3D open("/root/tasto1/value", O_RDONLY);
> pfd.events =3D POLLPRI | POLLERR;=20
>=20
> //ready =3D poll(&pfd, 1, -1);=20
> ready =3D poll(&pfd, 1, 100000);=20
>=20
> lseek (pfd.fd, 0, SEEK_SET);
>=20
> val =3D read(pfd.fd, buf, 254);
> //the output are: 1, 10, 10
> printf ("%d, %d, %d\n", ready, pfd.revents, pfd.events);
>=20
> printf ("%d, %s\n", val, buf );
>=20
> close(pfd.fd);
>=20
> But it don't wait for an edge but they exit immediatly.=20
> Why? where is the problem?

My Bad!

now work:

pfd.fd =3D open("/root/ledverde/value", O_RDWR );
while (1)
{
pfd.events =3D POLLPRI | POLLERR; // | POLLWRBAND;

lseek (pfd.fd, 0, SEEK_SET);

val =3D read(pfd.fd, buf, 254);
buf[val] =3D 0;
//printf ("%d, %s\n", val, buf );

ready =3D poll(&pfd, 1, -1);
printf("%d\n", ++i);
}


--=20
Mancausoft - http://www.mancausoft.org/
GPG key: B53F90F2

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