Re: How to access correctly serial port inside module?

[Jan Engelhardt <jengelh@linux01.gwdg.de>]

On May 24 2007 19:19, Lars K.W. Gohlke wrote:
> I want to read from serial port (I mean the port, which is called
> /dev/ttyS0 in user-space). Then I want copy_to_user() it through
> /proc/serialPort
>
> This is just to get familiar with driver programming (in kernelspace),
> it could be better done in userspace - I know. But this is for learning.
>
> It is a kind of synthetic problem, but after this, I hope too know how
> to handle further ones.
>
> Understood? It is a little bit strange, but hope it is explained well. ;)
>
> If tell me that for /dev/ttyS0 I can adept it to /dev/ttyS1 etc..


struct file *filp = filp_open("/dev/ttyS0");
char buf[4096];
mm_segment_t oldfs = get_fs();
loff_t pos = 0;

set_ds(KERNEL_DS);
while (vfs_read(filp, buf, sizeof(buf), &pos) > 0)
	printk("%s\n", buf);

filp_close(filp);



[I've warned about it... ;-) ]

	Jan
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