Doubt In Char Drivers

Doubt In Char Drivers

[me storage]

Hi All,

I am following LDD3 for Char Drivers. So we writing a kernel module(char
driver) after that creating a char file which is representation of
Character Device. So my doubt is how we will communicate with real hardware
device let suppose how to communicate with our monitor .
Can any one please explain how we will communicate with real hardware for
read/write calls?
And what is mknod is doing internally when we are creating char/block
devices?

Thanks in Advance
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Doubt In Char Drivers

[Victor Rodriguez]

HI

There is a good ( although really old ) explanation  about this here:

http://www.tldp.org/LDP/lkmpg/2.6/html/
http://www.tldp.org/LDP/lkmpg/2.6/html/x569.html

Please , just take it as a good ( and really old ) document to read
and understand more about the questions you have. Things on the kernel
have change a lot ( it was written in 2.6 )

In general you can try to make the experiment of turn on and off a led
( easier than the monitor )

Hope it helps ( at least this web page it was really helpful for me in
the beginign )

P.D. do not expect that the source code compile without modifications
in the current kernel :)

Regards

Victor Rodriguez



On Sun, Dec 28, 2014 at 12:39 PM, me storage <me.storage126@gmail.com> wrote:
> Hi All,
>
> I am following LDD3 for Char Drivers. So we writing a kernel module(char
> driver) after that creating a char file which is representation of Character
> Device. So my doubt is how we will communicate with real hardware device let
> suppose how to communicate with our monitor .
> Can any one please explain how we will communicate with real hardware for
> read/write calls?
> And what is mknod is doing internally when we are creating char/block
> devices?
>
> Thanks in Advance
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

Doubt In Char Drivers

[John de la Garza]

On Mon, Dec 29, 2014 at 12:09:30AM +0530, me storage wrote:
> Hi All,
> 
> I am following LDD3 for Char Drivers. So we writing a kernel module(char
> driver) after that creating a char file which is representation of
> Character Device. So my doubt is how we will communicate with real hardware
> device let suppose how to communicate with our monitor .
> Can any one please explain how we will communicate with real hardware for
> read/write calls?

did you see chapter nine?
http://lwn.net/images/pdf/LDD3/ch09.pdf

Doubt In Char Drivers

[Victor Rodriguez]

On Sun, Dec 28, 2014 at 1:10 PM, Victor Rodriguez <vm.rod25@gmail.com> wrote:
> HI
>
> There is a good ( although really old ) explanation  about this here:
>
> http://www.tldp.org/LDP/lkmpg/2.6/html/
> http://www.tldp.org/LDP/lkmpg/2.6/html/x569.html
>
> Please , just take it as a good ( and really old ) document to read
> and understand more about the questions you have. Things on the kernel
> have change a lot ( it was written in 2.6 )
>
> In general you can try to make the experiment of turn on and off a led
> ( easier than the monitor )
>
> Hope it helps ( at least this web page it was really helpful for me in
> the beginign )
>
> P.D. do not expect that the source code compile without modifications
> in the current kernel :)
>
> Regards
>
> Victor Rodriguez
>
>
>
> On Sun, Dec 28, 2014 at 12:39 PM, me storage <me.storage126@gmail.com> wrote:
>> Hi All,
>>
>> I am following LDD3 for Char Drivers. So we writing a kernel module(char
>> driver) after that creating a char file which is representation of Character
>> Device. So my doubt is how we will communicate with real hardware device let
>> suppose how to communicate with our monitor .
>> Can any one please explain how we will communicate with real hardware for
>> read/write calls?
>> And what is mknod is doing internally when we are creating char/block
>> devices?
>>
>> Thanks in Advance
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>

Hi

Due to the fact that I have found that many people ( including me at
the beginning ) is looking for simple and really short example code. I
decided (since your last mail, sorry I had free time :) ) to do a
compilation of basic modules examples(nothing big and still on
progress ). They are on my git
hub repository:

https://github.com/VictorRodriguez/linux_device_drivers_tutorial

You can download them with:

https://github.com/VictorRodriguez/linux_device_drivers_tutorial.git

There is a short README ( hope it helps )

Inside the repository there is a led.c file that you will find helpful
, It was tested on an old ARM platform. However it will work on any
other embedded platform . I will test it on a minnow max
(http://www.minnowboard.org/meet-minnowboard-max/)

The basic idea is the same, the key is to have the GPIO number :)

BTW. on the same git hub you will find another Linux projects under
construction ( HAL and PnP analysis )

If you have any question or feedback please do not hesitate to tell me

Regards

Victor Rodriguez

Doubt In Char Drivers

[Anuz Pratap Singh Tomar]

While we are on the topic of ldd, does anyone know where can the latest
source for ldd drivers be found?
I think Greg said someone is maintaining a repo kernel wise?
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Doubt In Char Drivers

[Siva Mannem]

Hi,

Please  check the below link.

https://github.com/duxing2007/ldd3-examples-3.x

Regards,
Siva Mannem.

On Sat, Jan 3, 2015 at 3:20 PM, Anuz Pratap Singh Tomar
<chambilkethakur@gmail.com> wrote:
> While we are on the topic of ldd, does anyone know where can the latest
> source for ldd drivers be found?
> I think Greg said someone is maintaining a repo kernel wise?
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>