Re: Runtime driver selection for a certain device

[Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>]

On 04/18/2011 09:22 PM, Grant Likely wrote:
> On Mon, Apr 18, 2011 at 1:22 PM, Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org> wrote:
>> Hallo,
>>
>> I'm looking for a solution for the following problem:
>>
>> A device may be served by more than one driver depending on the
>> application. Therefore the driver to use should be selectable at
>> run-time. Lets imaging 4 serial line devices normally handled by the
>> Linux serial driver. One of those needs eventually be handled by another
>> driver. How could that be realized, especially together with the device
>> tree, which is pretty static. Is there a generic way? The bind/unbind
>> functions look promising but it's not possible to register more than one
>> driver for a device.
> 
> Depends on the bus type.  I would look at registering the device in
> such a way that no driver will bind against it, and then change the
> configuration from userspace so the one of the drivers will get bound.

OK, I got a bit further. I think the following will work:

# echo f0002c00.serial > \
	/sys/devices/f0000000.soc5200/f0002c00.serial/driver/unbind

will unbind the driver for PSC6 and when I then load another serial
driver module, it will grap the unbound devices, e.g. PSC6 in this
example. But how can I avoid that the driver probes all relevant devices
when it's registered, or even better, how can I avoid automatic driver
binding for certain devices. I think that's not forseen, at least not
for the platform bus... but maybe I have missed something.

Thanks,

Wolfgang.