Re: [PATCH v3 10/15] leds: leds-gpio: Add ACPI probing support

Mika Westerberg
2014-10-01T11:59:07Z

On Wed, Oct 01, 2014 at 12:01:34PM +0200, Arnd Bergmann wrote:
> On Wednesday 01 October 2014 12:13:09 Mika Westerberg wrote:
> >
> > > Regarding the MODULE_DEVICE_TABLE, I suspect the above won't work the
> > > way you are hoping for, because once you get to dozens or hundreds of
> > > drivers doing this, each device will show up with the same string,
> > > so udev will try to load all the modules that list "PRP0001". That
> > > doesn't look right. With the code from patch 3, you can probably drop
> > > the acpi MODULE_DEVICE_TABLE() entirely and get the correct behavior.
> >
> > It actually works like this now:
> >
> > # cd /sys/bus/platform/devices/PRP0001\:00/
> > DRIVER=leds-gpio
> > MODALIAS=of:Nprp0001TacpiCgpio-leds
> >
> > # cat modalias
> > of:Nprp0001TacpiCgpio-leds
> >
> > In other words the modalias changes to be of:Nprp0001Tacpi, e.g
> > name=prp0001, type=acpi and then list of compatible values.
> >
> > Udev then loads only module that matches the modalias so it should not
> > load everything listing PRP0001 in their MODULE_DEVICE_TABLE().
>
> I'm not completely following yet. I can see how this works now, but
> how is this better than just using the existing modalias for OF?

You mean using just what of_device_get_modalias() would create? In that
case, what do we put to name and type fields?