On Wed, Oct 01, 2014 at 12:01:34PM +0200, Arnd Bergmann wrote:

On Wednesday 01 October 2014 12:13:09 Mika Westerberg wrote:

quoted

quoted

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?