Re: [RFC PATCH 0/3] introduce: Multistate Switch Class

[Greg KH <gregkh@suse.de>]

On Sun, Nov 27, 2011 at 04:09:19PM -0800, Dmitry Torokhov wrote:
> >> So for the userspace part it seems to me that we need to make
> >> up our mind about this stuff: is it going to be through input or
> >> uevent like in this patch? Or ?both??
> >
> >Input please, uevent is not for things like switches that are "common",
> >but for things that are "uncommon" and don't happen often.
> 
> Actually, please do not. I never liked audio-related switches added to
> input; ALSA guys just wore me down. These are usually not switches
> that user can flip, they are connections between components. Should we
> switch betide_carrier_*(), power supply state, etc, etc over to input?
> I think not.

Yes, I think so :)

Well, not all of them, but when there is a hardware change of state,
that a user can make happen (plug in headphone, plug in usb port, etc.)
they should be input events, as there are a zillion different ways to
have these types of devices.

And as HID has already documented almost all of these already, odds are,
there's already a HID mapping for what is needed to be exported, and if
not, it's easy to get a new HID code added, right?

> I haven't looked at the patch yet, but a class that has an attribute
> that could be queried and emitting uneventful on state change seems
> like a good diluting for me.

For this one case, maybe.  But what about the next one, and the next
one, and so on.  I would think those would all map better to input than
one-off class devices with custom uevent messages.

Unless we want to start piping input events through uevents?  :)

Ok, if you really don't want this, then I suggest we create something
that encompasses all of these into something unified, much like IIO is
trying to be for those types of devices.

thanks,

greg k-h