[MPCore Watchdog]: Convert from misc_dev to dynamic device node.

Jamie Iles jamie at jamieiles.com
Wed Jun 15 04:58:20 EDT 2011


On Tue, Jun 14, 2011 at 05:19:06PM -0700, Peter Fordham wrote:
> > On Tue, Jun 14, 2011 at 04:29:26PM -0700, Peter Fordham wrote:
> >> The current MPCore watchdog driver uses a misc_dev device node.
> >> This patch changes it to use dynamically allocated device numbers.
> >
> > I'm not sure that this is the correct thing to do.  All other watchdog devices
> > use a miscdevice with a major:minor of 10:130, is there a specific reason
> > that this node needs to be dynamic?
> 
> I was under the impressions that dynamic device nodes were the way of the
> future. Is that not the case?

Well they are for new devices/subsystems but watchdog has an established 
major:minor pair that all other devices use so you don't really have to 
worry about a namespace clash.

> I'll add the relevant checks in other places as per your suggestions.

I've added Wim (watchdog driver maintainer), but I would think that if 
this change is worth doing then it should be done for all drivers.

> > I believe the sysfs classes are pretty much
> > deprecated now in preference of a bus too.
> 
> Can you give me some more info here? I thought the sysfs stuff was the
> new right way of doing stuff. The class stuff allows udev to automatically
> create the right device node.

So here's one that I'm aware of https://lkml.org/lkml/2011/3/25/502.  So 
there's nothing wrong with using sysfs and a bus, but certainly a bus is 
preferred over a class.

Jamie



More information about the linux-arm-kernel mailing list