Re: best way to handle LEDs

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Thu, Nov 03, 2005 at 10:57:26AM +0100, Pavel Machek wrote:
> Hi!
> 
> > > Except the led code that is being proposed CAN sit on top of a generic
> > > GPIO layer.
> > 
> > I also have issues with a generic GPIO layer.  As I mentioned in the
> > past, there's serious locking issues with any generic abstraction of
> > GPIOs.
> > 
> > 1. You want to be able to change GPIO state from interrupts.  This
> >    implies you can not sleep in GPIO state changing functions.
> > 
> > 2. Some GPIOs are implemented on I2C devices.  This means that to
> >    change state, you must sleep.
> 
> Can't you just busywait? Yes, it is ugly in general, but perhaps it
> is better than alternatives...

Does the i2c layer support busy waiting or are you suggesting something
else?

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