Re: [PATCH 3/3] Input: add generic gpio brownout driver

[Trent Piepho <tpiepho@xxxxxxxxxx>]

On Mon, 2018-10-01 at 09:19 +0200, Marco Felsch wrote:
> On 18-09-28 17:19, Dmitry Torokhov wrote:
> > 
> > > 
> > > This patch adds the support for a generic gpio-based brownout
> > > detection. Upon a brownout the host system gets informed and the driver
> > > sends a keycode signal to the userspace. Per default this signal is
> > > mapped to KEY_POWER, so the system will shoutdown.
> > 
> > I do not believe this functionality should be exposed as an input
> > device, as it has nothing to do with human interaction with the
> > computing device. To me this is akin over-current on a USB port, or
> > carrier signal on network interfaces.
> 
> I'm still uncertain putting the code into the input framework. I tought
> a lot about the correct place. For me it's like a button, which is
> 'pressed' by the hardware. Yes, it's a bit abstract..

For quite a few years, the hwmon subsystem has had devices that will
generate an interrupt on low voltage (or high voltage, or high
temperature ...) and drivers that export that interrupt to userspace.

This device doesn't seem any different that a somewhat limited hwmon
device with just an "in0_alarm" attribute.