Hi all,
Im writing a char driver, my platform is an arm nommu (AT91).
The init function executes correctly in the uClinux startup. In the
application the device is opened and closed correctly, but when I try to use
the write function, the kernel doesnt execute my write function and the
function write in the application returns -1.
The code in the driver side is:
static int openflag_spi = 0;
static struct file_operations swspi_fops = {
read: spi_read,
write: spi_write,
open: spi_open,
release: spi_release,
}
static ssize_t spi_write (struct file *filp, const char *buf, ssize_t count,
loff_t *f_pos)
{
printk(spi_write: %s\n,buf);
return(count);
}
static int spi_open (struct inode *inode,struct file *filp)
{
if (openflag_spi )
return EBUSY;
MOD_INC_USE_COUNT;
printk(SWSPI: Open\n);
openflag_spi = 1;
return 0;
}
static int spi_release (struct inode *inode,struct file *filp)
{
printk(SWSPI: Close\n);
openflag_spi = 0;
MOD_DEC_USE_COUNT;
return 0;
}
The code in the application side is:
int fd;
char buf[80];
fd = open (/dev/swspi,rw);
if (fd == -1){
printf(\nUnable to open device\n);
return (-1);
}
printf(\nSpi device descriptor = %d\n,fd);
strcpy(buf,\nSWPI write function\n);
printf(write return = %d,write(fd,buf,sizeof(buf)));
And the execution is:
Sash command shell (version 1.1.1)
/>
/>
/> llaccess test
SWSPI: Open
Spi device descriptor = 3
write return = -1
SWSPI: Close
/>
Where is the problem? Why doesnt the kernel call to spi_write when the
application invokes the write function?
Thanks in advance
Ramón Flores
_______________________________________________
uClinux-dev mailing list
[email protected]
http://mailman.uclinux.org/mailman/listinfo/uclinux-dev
This message was resent by [email protected]
To unsubscribe see:
http://mailman.uclinux.org/mailman/options/uclinux-dev
