Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 15 May 2007 01:00:07 +0200 | From | Tilman Schmidt <> | Subject | Re: How to access correctly serial port inside module? |
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Am 14.05.2007 22:00 schrieb Jan Engelhardt: > On May 14 2007 19:40, Lars K.W. Gohlke wrote: >>> >>> after searching the mailing list and searching the web, I still don't >>> know how to access correctly the serial port (in user space known as >>> /dev/ttyS01) > > http://kernelnewbies.org/FAQ/WhyWritingFilesFromKernelIsBad
That's not nice, sending a newbie on a wild goose chase like that. He doesn't want to write to a file from kernel after all. Reading FAQs is never bad, of course, but reading that particular one won't help him at all with this questions.
Lars: Read that at your leisure if you have time. It is quite educating, though completely irrelevant to your questions.
>>> would somebody be so kind to give me an example: >>> >>> with this behaviour: >>> >>> 1. read from port >>> 2. output via printk() >>> 3. write to port > > inb/inw/inl, printk, outb/outw/outl.
This is even less nice. You're sending him down the road of directly programming UART registers, knowing full well (I hope) that this a Bad Thing. What will you tell him when he comes back covered in bruises?
Lars: Ignore this advice. You don't want to use in[bwl]/out[bwl] to directly access serial port hardware for which the kernel has a working driver already. That way lies pain, as I know from experience. Read up on the line discipline interface instead, as described in my previous reply.
HTH T.
-- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite)
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