Re: [PATCH] ARM: Kirkwood: Add DT description of QNAP 419

On Wednesday 15 January 2014 18:45:19 Andrew Lunn wrote:

quoted

quoted

But i'm also a little bit concerned by the "unique number" and this
ending up in /dev/input/by-path/platform-gpio_keys.3-event. Is this
path supposed to be stable? This unique number is not stable. An
unwitting change to the DT could cause its value to change. Do we need
to make it stable?

One possibility would be to create an artificial bus in DT for all
gpio-keys devices, use #address-cells=<1> and #size-cells=<0>
for it, and give each device a unique reg property. Not sure if that
would be considered an elegant solution though.

Hi Arnd

Can i imply from your answer that you think 

/dev/input/by-path/platform-gpio_keys.3-event

should be stable?

No, I have no idea whether it should be or not. I was just trying
to come up with a way to make it stable if that's desired.

A quick look at udev rules seems to suggestion this is an issue for
input/gpio-keys and maybe audio and video if there is a top level DT
property collecting the different sub devices together for ASOC and
V4L.

For some other subsystems, we have entries in /aliases/ to sort
them. Maybe that would work here to get a stable path independent
of the location in DT.

	Arnd