Re: [RFC] Wiimote userspace interface

On Wed, 3 Aug 2011, David Herrmann wrote:

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There is also the other side. Sending data to the wiimote. 4 LEDs can
be set, the rumble motor can be enabled/disabled and audio data can be
streamed. I think my current approach to use sysfs attributes for the
LEDs

Depending on what exactly it is you may try registering LEDs as LED
class devices. Having a sysfs attribute to light one of 4 leds is an
option too.

I already looked at the API. Although the 4 LEDs of the wiimote can
only be switched on/off (no brightness modulation) I think I could
register 4 led_classdev structures. This would also allow software
blinking.

Yes, I'd prefer that as well.

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and RUMBLE motor is ok? I can't figure out any better way here.

One of the input devices should be registered as ForceFeedback device
(or you create a separate FF input device).

Ok, I will add that.

Perfect, thanks. You can find quite some examples of force feedback 
implementations even in drivers/hid as well, to gain some inspiration.

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Reference-counting doesn't make sense. If multiple devices use them,
then they will always have conflicts, however, it still works.
Audio streaming is not yet implemented, but I think I could register
an alsa device so this needs not to be discussed here.


Currently I think Interface #2 would be the best way but I don't want
to spend time implementing that if you tell me it isn't acceptable.
Any comments on this are appreciated.

I believe you should try presenting physical objects as input devices so
I'd try presenting wiimote (with optional motion+ events) as one device
and accessory (nunchuck, classic extension) as another device.

Yes, but the problem is, that this would enable all peripherals of the
wiimote, even though userspace may not need them. But if that is the
recommended way, I will implement it.

Is there any problem with that? I could potentialy imagine unnecessary 
power consumption (assuming that the peripherals that are not enabled are 
in some lower state, right?). Anything else?

Thanks a lot for your work on the driver, David.

-- 
Jiri Kosina
SUSE Labs