Re: [PATCH v3 3/3] leds: trigger: implement a tty trigger

From: Greg Kroah-Hartman
Date: Tue Dec 17 2019 - 12:21:08 EST


On Tue, Dec 17, 2019 at 05:23:13PM +0100, Uwe Kleine-König wrote:
> On Tue, Dec 17, 2019 at 04:27:24PM +0100, Greg Kroah-Hartman wrote:
> > On Tue, Dec 17, 2019 at 04:07:36PM +0100, Uwe Kleine-König wrote:
> > > Usage is as follows:
> > >
> > > myled=ledname
> > > tty=ttyS0
> > >
> > > echo tty > /sys/class/leds/$myled/trigger
> > > cat /sys/class/tty/$tty/dev > /sys/class/leds/$myled/dev
> >
> > Is this the correct instructions? Aren't you looking for a major/minor
> > number instead in your sysfs file?
>
> This is correct, yes, at least it works as intended on my machine.
>
> /sys/class/tty/$tty/dev produces $major:$minor and that's what the
> led-trigger consumes.

Ugh, nevermind, I totally read that wrong, I was thinking "echo" instead
of cat. My fault, what you wrote is correct. Should that be documented
somewhere in a Documentation/ABI/ file so that people know how to use
this new sysfs file? How are led triggers documented?

thanks,

greg k-h