[PATCH] leds-alix2: add support for button connected to J15

[Daniel Mack]

Hi,

for a project I was working on, we used the J15 connector of the ALIX.2D
board (which is connected to a GPIO of the CS5536 Geode companion chip)
for an external button switch.

I thought it might be worth sharing this piece of code, so others can do
the same.

There is, however, a small hardware modification is necessary as the pin
is also shared as buzzer output. I noted that in the Kconfig entry.

The patch should go thru Richard's led-2.6.git as it depends on another
one that has been queued there already.

Thanks,
Daniel