Hi Peter, Ezequiel, Thomas,
On Thu, Oct 04, 2012 at 08:38:32AM +0200, Peter Korsgaard wrote:
> >>>>> "Ezequiel" == Ezequiel Garcia <elezegar...@gmail.com> writes:
>
> Hi,
>
> >> Still it doesn't make this driver really useful as a template. The best
> >> templates are quite certainly the existing drivers in drivers/<foo>/,
> >> where <foo> in the subsystem you are writing a driver for.
>
> Ezequiel> To add some value to this argument, video4linux subsystem has
> Ezequiel> a couple of template drivers -fully maintained- called vivi
> Ezequiel> and mem2mem_testdev.
>
> Ezequiel> These are the starting point of any v4l developer.
>
> Ezequiel> Adding more drivers like these to other subsystems
> Ezequiel> -mainlined, of course- would be more worthy than maintaining
> Ezequiel> a general template of them off-tree.
>
> I agree. It needs to be focused on the specific subsystem and not
> something trying to do everything.
The question remains whether there is a place for demo code of basic Linux
driver development mechanisms and concepts when treated by themselves, and not
as part of a specific subsystem? Or is the existing body of code under
drivers/ enough?
The problem I see with the subsystem only approach is that basic mechanisms
don't get the attention they need. Apart from the excellent (and increasingly
becoming outdated) book of Linux Device Drivers (which also includes the demo
scull driver that Tim has mentioned), I'm not aware of demo code we can point
kernel newbies at, that explains the basic ingredients of a kernel driver.
Here is a list of the concepts that I'm thinking of (most of which are covered
in Constantine's driver template):
1. interrupt handling
2. tasklets
3. work queues
4. completion
5. kfifo
6. kthread
7. timers
8. locking primitives
9. linked lists
10. debugfs
11. kernel module
12. probe
13. instance private state struct
In my opinion, there is a place in the mainline kernel for a live, constantly
evolving, body of code serving as demo for the above listed and other relevant
concepts.
baruch
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- bar...@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
_______________________________________________
Celinux-dev mailing list
Celinux-dev@lists.celinuxforum.org
https://lists.celinuxforum.org/mailman/listinfo/celinux-dev
