devfs Gpio and interrupt

devfs Gpio and interrupt

[Mancausoft]

[-- Attachment #1: Type: text/plain, Size: 1253 bytes --]

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 
# cat /root/tasto1/direction
in

# cat /root/tasto1/value 
1

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

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

# cat /sys/kernel/debug/gpio 
[...]
 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 
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 = open("/root/tasto1/value", O_RDONLY);
pfd.events = POLLPRI | POLLERR; 

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

lseek (pfd.fd, 0, SEEK_SET);

val = 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. 
Why? where is the problem?

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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: devfs Gpio and interrupt

[Mancausoft]

[-- Attachment #1: Type: text/plain, Size: 966 bytes --]

On 15:22 Wed 09 Feb     , Mancausoft wrote:
> I read gpio.txt in Documentation of kernel and try to use it.
> pfd.fd = open("/root/tasto1/value", O_RDONLY);
> pfd.events = POLLPRI | POLLERR; 
> 
> //ready = poll(&pfd, 1, -1); 
> ready = poll(&pfd, 1, 100000); 
> 
> lseek (pfd.fd, 0, SEEK_SET);
> 
> val = 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. 
> Why? where is the problem?

My Bad!

now work:

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

lseek (pfd.fd, 0, SEEK_SET);

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

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


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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]