Thomas Eschenbacher wrote:
>
> Hallo,
>
> is there any simple way to access an RT device driver from user space?
>
> My problem is that we have a C library that has to access a serial ports
> /dev/ttyS0 through the "rt_com" driver.
>
> I use rtlinux-2.2, kernel-2.2.14/i386 and the rt_com-0.4. The kernel,
> modules and examples work fine, even the examples in rt_com do work
> (open the port, send bytes etc.). The device driver uses char-major-60
> and the serial driver of the linux kernel is removed.
> I did "rm /dev/ttyS0" and "mknod /dev/ttyS0 c 60 0".
>
> The example modules are able to call open("/dev/ttyS0", O_RDWR),
> but if I copy this line to a sample program I always get -1 as return
> value?
>
> can anybody explain me why???
>
> thanks,
> Thomas.
> --
>
Do a ls -l /dev/ttyS0
The permissions may be set so that only root can open for read / write
Regards
phil Wilshire
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