Re: Please pull linux-2.6-mpc52xx.git

[Richard Purdie <rpurdie@rpsys.net>]

On Tue, 2008-03-18 at 08:47 -0600, Grant Likely wrote:
> On Tue, Mar 18, 2008 at 2:29 AM, Bartlomiej Sieka <tur@semihalf.com> wrote:
> >  Grant,
> >
> >  Yes, the Motion-PRO LED driver has been reworked and posted:
> >  http://patchwork.ozlabs.org/linuxppc/patch?q=Motion-pro&id=16617
>
> Okay, I've taken another look at the driver and I've figured out what
> has been bothering me about it.  It seems to me that the motion pro
> led driver is just the first of many that we will see (seeing as some
> many people find the blinking lights rather soothing) and it's a non
> trivial amount of code.
> 
> (Note: I'm not actually opposed to this driver if Richard is okay with
> it; but I do think that in the long term we should move towards a more
> generic approach)
> 
> In essence, this driver sets up two GPIO pins to drive LEDs.  A pretty
> common approach for putting LEDs on a board.  In this case each GPIO
> bank only contains 1 pin; but I imagine that on other boards there
> will be multiple pins in a GPIO bank, only some of which actually used
> for blinking LEDs.
> 
> I've started thinking that it would be better to split things up in
> the device tree to have one node for each GPIO block and a single LED
> node that maps LEDs to gpio pins.  That would allow a common driver to
> be written for all GPIO driven LEDs with a single block of device tree
> parsing code.  Plus, it allows other devices to use GPIO pins within
> the same block (not an issue for the motion pro board; but when other
> boards start coming on-line it would allow us to reduce the amount of
> board specific code).  Finally, it means that the timer pin GPIO
> driver can be used for more than just flashing an attached LED.

I don't mind having a specific driver but I don't know anything about
the hardware its creating the interface for so I need the community's
help with that part. There is drivers/leds/leds-gpio.c if that would
work better.

Regards,

Richard