On Wed, 4 May 2011, Daniel Baluta wrote:
> > so rather than the canonical combination of cdev_init() and
> > cdev_add(), this appears to register the pre-defined DSP56K major
> > number, then goes straight to registering the driver with sysfs.
> >
>
> Check register_chrdev code. [1]
> As you can see register_chrdev does cdev_alloc + cdev_add.
>
> > is this now an alternative way of registering character drivers, if
> > you want to register them with sysfs as well? as i read it,
> > device_create() will create the /dev file so is this just a newer way
> > to register character drivers?
>
> Yes, it is an alternative way of registering chrdev, but it doesn't have
> anything to do with sysfs layer.
>
> * device_create
> * creates a device object and link it into sysfs tree.
> * generates an event -> udev creates /dev/ file in userspace.
> * register_chrdev - reserves major/minor and sets up char device
> file operations.
> >
> > i don't think i've run across any other drivers that have this
> > structure but, then again, i haven't been looking that hard. yet.
>
> thanks,
> Daniel.
>
> [1] http://lxr.linux.no/linux+v2.6.38/fs/char_dev.c#L264
yes, shortly after i asked, i refreshed my memory and teased out
most of the above, nice to have it confirmed, though. thanks.
rday
--
========================================================================
Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
========================================================================_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
