GTA03 LED controller: LP5521

Werner Almesberger werner at
Tue Nov 18 10:35:32 CET 2008

Andy Green wrote:
> There's a choice about using the userland i2c stuff to access the
> storage for the program or having a driver at all.

All in user space. Even better !

>  If we have a driver,
> we probably make a /sys you dump the LED state machine binary "program"
> down to set it.  That's probably as far as we should take it if even
> that far.

Yup, or hex, like the driver Andrzej mentioned.

> What would guide us towards having a driver is if kernelside could want
> to use the LEDs itself, eg, to indicate panic.

Panic indication would seem a valid excuse for having something in
the kernel, yes. But that could also be just a "panic-only" driver.
It may have to violate quite a few rules anyway, to be able to get
through to the LED controller when the system is in trouble.

We don't have any easily GPIO-accessible LED, do we ?

- Werner

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