[Javier Martinez Canillas]

On Mon, Oct 15, 2012 at 12:53 PM, Niroj Pokhrel <nirojpokhrel at gmail.com> wrote:
> Thank Matthias!!!
> I have tried using printk . What I really want to do now is to implement the
> methods I have written by calling from the user space. Like I want to read
> or write to the character devices via  user space.
>

Hi Niroj,

Please don't top post, it is not polite since forces readers to scroll
to the bottom to gain some context about the conversation.

> On Mon, Oct 15, 2012 at 3:49 PM, Matthias Brugger
> <matthias.bgg at googlemail.com> wrote:
>>
>> Hi,
>>
>>
>> On 10/15/2012 11:24 AM, Niroj Pokhrel wrote:
>>>
>>> Hi,
>>> I'm new to linux and kernel . I'm ongoing with the linux device drivers.
>>> I've followed the the book LDD but i'm lost about how to call my
>>> driver's specific method from the user space.
>>> Eg: if have developed a character device and inserted the module then
>>> how can i make sure that when I read or write that it implement the
>>> functions via the methods i have implemented in my module.
>>
>>
>> the most easy way would be to put some printk output in your read/write
>> functions of your driver. So with cat/echo from userspace you should be able
>> to verify your implementation.
>>
>> Regards,
>> Matthias
>>
>>>
>>> --
>>> Niroj Pokhrel
>>> NIT Jamshedpur,
>>> B.Tech,Electronics and Communication
>>>
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>
>
>
>
> --
> Niroj Pokhrel
> NIT Jamshedpur,
> B.Tech,Electronics and Communication
>

There is no need to implement anything in user-space.

If your char dev driver has been correctly implemented and registered
then the standard file operation syscalls can be used to access the
device. The Linux kernel virtual filesystem will use the information
on the character device node (major number) to know which struct
file_operations (and hence file operations callbacks) has to be used.

Hope it helps,

-- 
Javier