On Sun, Sep 12, 2010 at 01:30:26PM +0530, Bond wrote:
> On Sat, Sep 11, 2010 at 11:31 PM, Josh Cartwright <joshc@xxxxxxxxx> wrote:
>
> > To 'bind' to a device means that your driver is asserting control of the
> > device.
>
> You mean to say the driver is trying to take control of the device.
Yes. If your driver is bound to a device, it has exclusive control over
it.
> > On the previous slide, a USB device ID table was created that lists the
> > IDs of the devices the driver supports.
>
> Do you mean to say that it is possible that same driver support
> multiple devices?
> I have no clue of it.
Yes, it is quite common for a driver to control devices with different
IDs.
> > When your driver registers to
> > the USB core (via usb_register()),
>
> Can you point me which slide in the presentation I gave link is meaning this
> type of thing.
I only briefly looked at the presentation, I'd suspect its in there, but
I'm not going to look for it for you, you can manage that yourself.
> > the core code looks at the list of unclaimed devices and your
> > provided ID table and calls your probe() for any matches.
> >
> > Your probe() callback is responsible for returning 0 if it wants to
> > 'bind' to the device, otherwise you return an error.
> >
> Is 0 for success.
Yes.
> I see a structure
> static struct usb_driver {
> .owner :
> .name :
> .probe :
> .disconnect :
> .id_connect :
>
> }
> I am not clear as how this structure has mapped to functions.
You're responsible for populating the members of this structure with
your callback functions, and then passing it to usb_register().
> What my understanding of writing a device driver till now from my search on
> Internet is
>
> reserve a set of major and minor number
> define a file_operations structure associating to function pointers
> we need to define operations corresponding to system calls an application
> can apply
This would be enough for your driver to communicate to userspace, but it
is certainly not enough for your driver to communicate to your device
via usb.
> if I were to take above three points then on the link
> http://www.kroah.com/linux/talks/ols_2005_driver_tutorial/index.html
> which slide is doing that?
Again, you can look through the slides. Also you should read LDD3, as
it covers alot of your questions.
--
-joshc
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