How does the driver initialize corresponding with several same devices ?

Philipp Ittershagen p.ittershagen at googlemail.com
Wed Apr 18 07:07:09 EDT 2012


On Wed, Apr 18, 2012 at 04:32:12PM +0530, anish singh wrote:
> On Wed, Apr 18, 2012 at 4:18 PM, Philipp Ittershagen
> <p.ittershagen at googlemail.com> wrote:
> > On Wed, Apr 18, 2012 at 05:16:01PM +0800, Li Haifeng wrote:
> >> I make a driver module and built in the kernel. There are three devices use
> >> the same driver on the hardware platform. To use each device, the probe
> >> function of the driver module should be probed. So, the driver module is
> >> registered in the kernel.
> >>
> >> My question is, how times should the probe function of the driver be called
> >> and create nodes in devfs to corresponding with the three devices?
> >
> > It depends on what your architecture supports. If you have support for device
> > tree, your entry in the device tree will make the subsystem call your probe
> > function for each device it finds. You can then check the `compatible` entry
> > of the device node and your driver is then able to register itself to the
> > kernel subsystem.
> Without device tree what would be your answer as i guess device
> tree has come recently in picture but not sure.

Let me rephrase your question and see if I understand it correctly. You have a
probe function which already gets called for each device in your platform and
you want to know how to make each device accessible in userspace (using i.e.
devfs nodes) ?

Greetings,

  Philipp



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