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

Arnd Bergmann
2014-10-01T10:01:34Z

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?

Arnd