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SubjectRe: How to access correctly serial port inside module?
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Tilman Schmidt schrieb:
> Am 03.06.2007 22:28 schrieb Lars K.W. Gohlke:
>> Tilman Schmidt schrieb:
>>> Am 17.05.2007 08:15 schrieb huang ying:
>>>> I think the "serio" (through drivers/input/serio/serport.c) may be a
>>>> choice too, like that in linux/drivers/input/mouse/sermouse.c, which
>>>> is an example to program serial port in kernel space.
>>> Interesting. I wonder if that would have been a better choice for
>>> the Gigaset M101 driver. It seems even to have a probe mechanism
>>> so one could try to determine if the expected device is really
>>> connected to the port.
>>> Is there any documentation on this interface? I find the source a
>>> bit hard to understand, sparsely commented as it is.
>> how can I open ttyS1 with major=4 and minor=65?
>
> a) With "my" approach, ie. writing a line discipline, you open
> /dev/ttyS1 in a user space program and then push your line discipline
> onto it using ioctl(,TIOCSETD,).
>
> b) With the "serio" approach, if the probe mechanism is really what
> I think it is, you register your probe function and wait for it to
> be called for each active serial port, then do your thing to determine
> whether this is a/the port you want to use.
>
>> Does anybody have some code to read from it the first e.g. 2bytes?
>
> That's not how things work in the kernel. You don't "read the first
> <n> bytes" at will. You have to provide means to process whatever
> data happens to arrive on the serial port, as it arrives.
>
> a) With a line discipline, you provide a callback function
> ".receive_buf" which will be called by the serial driver if some
> data has been received, and has to process that data then and there.
> You might just stow it away in a buffer of course, provided you
> are sure to get around to processing it later.
>
> b) With the "serio" interface, it seems the ".interrupt" function
> serves the same purpose - though, as I said, I am not really
> competent on that topic.
>
> HTH
> T.
>
ok because I want to handle it in kernel space I will no take option a)

I will try it the way of b)

anyway thx.
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