Re: [PATCHv2 3/4] ARM: tegra: use build-in device properties with rfkill_gpio

[Marc Dietrich]

Am Dienstag, 23. Februar 2016, 11:31:40 CET schrieb Arnd Bergmann:
> On Tuesday 23 February 2016 11:15:31 Arnd Bergmann wrote:
> > On Thursday 18 February 2016 21:04:49 Johannes Berg wrote:
> > > On Tue, 2016-01-26 at 09:42 +0100, Johannes Berg wrote:
> > Just for my curiosity: what is the difference between a rfkill-gpio
> > device and a gpio-keys device with a KEY_RFKILL code?
> > 
> > arch/arm/boot/dts/bcm4708-netgear-r6250.dts and others seem to
> > do the second approach in DT so they don't need to create the
> > platform device.
> 
> I found the answer now (after discussing on IRC): just
> for reference: KEY_RFKILL is for sending the event to the kernel
> when a user presses the gpio butting, this rfkill-gpio turns
> the devices on or off when after an RFKILL event is received.

yes, paz00 has no hw key. rfkill is triggered via software (rfkill) only. The 
problem in the past was how to describe such a device in the device tree. 

Strictly speaking, there is no rfkill device hardware (just an interface). The 
only hardware that exists is in our case is connected to a hard wired usb bus 
(wifi dongle), which makes it complicated to attach a DT property or subdevice 
to it. And a standalone device-tree entry for a non hardware device was 
rejected in the past.

Marc

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