Re: [PATCH 2.6.8.1 0/2] leds: new class for led devices

From: Russell King
Date: Fri Sep 03 2004 - 17:29:06 EST


On Fri, Sep 03, 2004 at 06:47:23PM +0000, John Lenz wrote:
> On 09/03/04 07:06:34, Jan-Benedict Glaw wrote:
> > Is idle/timer/power hardware-controlled (eg. by a secondary processor,
> > direct chipset implementation) or is switching on/off controlled by
> > kernel (eg. heartbeat, IO and ethernet for the LEDs you can find on some
> > PA-RISC machines)?
>
> Right now the kernel is in sole control. The device I am testing this on
> is a Sharp Zaurus SL5500, which has two leds that by default are used to
> light when new mail arrives and if the power is plugged in.

The kernel is NOT in sole control today on ARM platforms:

echo claim > /sys/devices/system/leds/leds0/event
echo red on > /sys/devices/system/leds/leds0/event
echo green on > /sys/devices/system/leds/leds0/event
echo red off > /sys/devices/system/leds/leds0/event
echo release > /sys/devices/system/leds/leds0/event

etc

Sure, we have a weird naming scheme (red, green, amber, blue) but
that came around because that's what people were dealing with.
There's nothing really stopping us from having any name for a LED
in the existing scheme.

I just don't buy the "we must have one sysfs node for every LED"
argument.

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/
2.6 Serial core
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